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Cardiovascular Adjustments to Thermal Stress

Loring B. Rowell

10.1002/cphy.cp020327

Source: Supplement 8: Handbook of Physiology, The Cardiovascular System, Peripheral Circulation and Organ Blood Flow

Originally published: 1983

Published online: January 2011

Full Article on Wiley Online Library



Abstract

The sections in this article are:

1 Critique of Some Methods Employed in Humans
1.1 Total and Regional Cutaneous Blood Flow
1.2 Cardiac Output
1.3 Central Blood Volume
1.4 Regional Blood Flow
1.5 Measurement of Temperature
2 General Features of the Cutaneous Circulation: A Brief Review
2.1 Cutaneous Blood Flow
2.2 Cutaneous Blood Volume
2.3 Innervation of Cutaneous Arterioles
2.4 Local Control of Skin Blood Flow: Interaction With Reflexes
2.5 Reflex and Local Control of Cutaneous Veins
3 Circulatory Adjustments to Heat Stress in Resting Humans
3.1 Changes in Cardiac Output, Blood Pressure, and Blood Volume
3.2 Distribution of Cardiac Output in Heat‐Stressed Resting Humans
3.3 Cardiac Output and Its Distribution in Heat‐Stressed Resting Subhuman Species
3.4 Distribution of Blood Volume in Heat‐Stressed Resting Humans
3.5 Mechanisms of Blood Flow Redistribution in Rest
3.6 Acclimatization in Rest
4 Interaction Between Thermoregulatory and Nonthermoregulatory Reflexes in Control of Skin Blood Flow
4.1 Cutaneous Vascular Responses to Baroreflexes
4.2 Cardiopulmonary (Low‐Pressure) Baroreflex
4.3 Postural Influences: Hydrostatic Problem
4.4 Upright Posture in Heat Stress: Interaction Between Reflex Vasoconstriction and Vasodilation
4.5 Exercise
4.6 Possible Modes of Reflex Interaction: Unsolved Problems
5 Overall Circulatory Adjustments to Heat Stress and Exercise
5.1 Distribution of Blood Volume
5.2 Redistribution of Blood Flow During Exercise
5.3 Central Circulation
5.4 Adaptation to Heat Stress and Exercise: Acclimatization
Figure 1. Figure 1.

Comparison of simultaneous measurements of splanchnic blood flow (SBF) by constant‐dye‐infusion technique 44 and by electromagnetic flowmeters on hepatic artery and portal vein (solid and open circles) or by direct flow measurement (crosses) 106,266,384.

From Rowell 345, reproduced by permission of Grune & Stratton
Figure 2. Figure 2.

Simultaneous measurement of renal blood flow by p‐aminohippurate clearance (dashed line, left kidney) and electromagnetic flowmeter (solid line, right kidney) during graded hemorrhage, which lowered mean arterial pressure (MAP; top panel) and increased renal nerve activity (second panel).

Adapted from Selkurt 385
Figure 3. Figure 3.

Schematic illustration of blood volume distribution and venous pressures in upright human compared with those in the dog (and most other animals).

Adapted from Folkow and Neil 131
Figure 4. Figure 4.

Relationship between venous pressure in leg veins and volume of blood contained at 3 different leg skin temperatures (Tsk). Rise in local Tsk increases the blood volume contained in cutaneous veins at a given venous distending pressure; i.e., venous compliance increased.

Redrawn from Gauer and Thron 153; from Rowell 346
Figure 5. Figure 5.

Right and left forearm blood flows in 1 subject with congenital absence of sweat glands (anhidrotic ectodermal dysplasia) during direct whole‐body heating (forearms were not heated). Forearm blood flows showed almost no increase in response to a 1.5°C increase in Tc. In normal skin this would raise blood flow to 20–30 ml · min−1 · 100 ml−1 of forearm, the increment being confined to skin.

From Brengelmann, Rowell, et al. 48
Figure 6. Figure 6.

Cardiac output rose ∼6 liters/min, and forearm blood flow rose to 20 ml per 100 ml of forearm per min in 1 subject who was indirectly heated (legs in hot water) for 100 min, which raised body core temperature by 2.6°C. Heart rate, HR; stroke volume, SV.

From Koroxenidis et al. 263
Figure 7. Figure 7.

Circulatory responses to whole‐body heating to limits of thermal tolerance in a representative subject. Elevation in skin temperature (Ts) by water‐perfused suit raised rectal temperature (Tr) and right atrial blood temperature (Tb), cardiac output (CO), HR, SV, and central venous pressure (CVP). Note time courses of changes in aortic mean and pulse pressures (Ao BP) and right atrial mean pressure (RA‐MP). Total peripheral resistance, TPR.

From Rowell et al. 356
Figure 8. Figure 8.

Average circulatory responses in directly heated subjects. Initial and final values and approximate time course are shown for Ts and right atrial blood temperature (Tblood) and each cardiovascular variable. Changes in cardiac output and splanchnic, renal, and muscle blood flow contributing to increased skin blood flow are shown in separate boxes.

From Rowell 340
Figure 9. Figure 9.

Time course of changes in splanchnic blood flow (SBF) and splanchnic vascular resistance (SVR) (open triangles) during prolonged whole‐body heating (as in Figs. 7 and 8) in 7 subjects 352,358. Solid line in top panel, approximate time course of Tra (Tb) during heating.

From Rowell 340
Figure 10. Figure 10.

Left, estimated distribution of cardiac output between skin and other major organs at rest in normothermia; right, during severe hyperthermia (Tc greater than 39°C).
Figure 11. Figure 11.

Open bars, distribution of blood flow (radioactive microspheres) in 8 conscious baboons during quiet, seated rest in normothermic and hyperthermic (Tc increased 1.5°C‐2.0°C) conditions (cross‐hatching). Note insignificant rise in brain blood flow with heating. One SE and significance of change (*P < 0.05, **P < 0.01) are shown. Central nervous system, CNS.
Figure 12. Figure 12.

Blood flow (by microsphere technique) to various cutaneous regions during normothermic control period (solid bars) during moderate hyperthermia (Tc rose 1.5°C‐2.0°C) in resting, awake baboons (open bars, 0.5 SE shown where discernible).

From Hales, Rowell, and King 196
Figure 13. Figure 13.

Schematic illustration of altered distribution of blood volume in a heat‐stressed man. In contrast most species have small hydrostatic influence and small cutaneous vasodilation. Substantial vasodilation occurs in the dog tongue.
Figure 14. Figure 14.

Left, Krogh's 267 simplified model of the cardiovascular system divided into 2 circuits, 1 compliant (long time constant) and 1 noncompliant (short time constant). Right, electrical equivalent of a generalized parallel‐compartment model of the peripheral circulation. Arterial resistance, Ra; venous compliance, Cv; venous resistance, Rv (Rv2 and Cv2 illustrate variable resistance and compliance of cutaneous veins); arterial compliance, Ca. Venous time constant for a particular circuit (τ) is RvCv.

Left, adapted from Caldini et al. 67; right, adapted from Mitzner and Goldberg 298
Figure 15. Figure 15.

Hydraulic model contrasting effects of increasing blood flow through noncompliant (panel A) versus compliant circuits (panels B, C, D). Vasodilation of compliant circuits with long time constants (RvCv, in Fig. 14) depletes the volume (vol) of central reservoirs [central blood volume (CBV) or heart and pulmonary vessels]. Vasoconstriction (VC) of compliant circuits passively displaces their volumes to partially restore CBV.
Figure 16. Figure 16.

Schematic illustration of how volume may be mobilized passively from splanchnic veins as cutaneous veins fill up during heat stress. Fall in CVP creates a pressure gradient from right atrium to hepatic veins. Constriction of splanchnic arterioles further lowers splanchnic venous pressure and translocates more volume to the heart. Because of steep splanchnic venous pressure‐volume curve (right), a small decrease in venous pressure displaces a large volume of blood. GI, gastrointestinal tract.
Figure 17. Figure 17.

Relationship between heart rate and plasma norepinephrine concentration in cancer patients treated with hyperthermia (to 41.5°C).

From Kim et al. 249
Figure 18. Figure 18.

Relationship between SBF as percent of resting SBF and heart rate (HR) during exercise in neutral and hot environments 340 and before (open squares) and after (solid squares) physical conditioning 82. Data are compared with renal blood flow (RBF) during exercise 182. Regression lines for SBF versus HR in resting human stressed by heat and lower‐body negative pressure (LBNP) are displaced to the left (cf. norepinephrine data in Fig. 19) 340.

Adapted from Rowell 345
Figure 19. Figure 19.

Relationship between increase in plasma norepinephrine (NE; ng/ml) and change in HR during quiet standing (open and closed triangles) and during supine exercise (closed circles). Note the rightward displacement on HR axis during exercise (cf. Fig. 18).

Adapted from Christensen and Brandsborg 79
Figure 20. Figure 20.

Average responses to gradual decline in right atrial pressure (RAP) induced by slow ramp (‐1 mmHg/min) of lower‐body negative pressure (LBNP). Note that aortic mean pressure (MP), aortic pulse pressure (PP), and HR (and also aortic dP/dt, not shown) remained constant during the first 20 min of LBNP, whereas RAP fell to 0 mmHg, SBF decreased 10%, and FBF decreased by 35%. Results suggest that falling RAP, which unloaded cardiopulmonary stretch receptors, elicited regional vasoconstriction.

From Johnson, Rowell, et al. 240, by permission of the American Heart Association, Inc
Figure 21. Figure 21.

Relationship between percentage increase in splanchnic vascular resistance (δSVR %) and increase in plasma renin activity (APRA; ng of angiotensin I generated per 100 ml per 3 h) during prolonged whole‐body heating (as in Figs. 7 and 8; ref. 19).
Figure 22. Figure 22.

Results from 1 subject in whom body skin temperature (Ts) was driven in different temporal patterns to achieve periods of separation between changes in Ts (top panel) and central temperature [right atrial blood temperature (Tra.) and esophageal temperature (Tes); second panel]. Note close correspondence between rising Tra, sweat rate (SR), and forearm skin blood flow (FBF). Separate influences of Tra and T. on FBF, SR, and heart rate (HR) were determined mathematically. Influence of Tra on FBF was 20 times greater than that of Ts. per °C.

From Wyss, Rowell, et al. 466
Figure 23. Figure 23.

Results from 1 subject in whom body skin temperature (Ts) was controlled and driven in different patterns to reveal influences of body Ts, rate of change of Ts (, top panel), and central body temperature [esophageal temperature (Tes) and right atrial blood temperature (Tra)] on heart rate (HR), sweat rate (SR), and FBF. Note small effect of increasing Ts on FBF. Most increases in FBF and all the increase in SR attended increased Tra; Ts and had no influence on FBF when altered after elevation of Ts to 38°C for 30 min. Note also maintained high FBF long after SR had fallen. Central and cutaneous influences on FBF were determined by multiple linear regression for FBF, HR, and SR against Tra or Tes Ts, and during periods A, B, and C (top). In periods A and B, influence of Ts and on FBF was minimal.

From Wyss, Rowell, et al. 467
Figure 24. Figure 24.

Schematic illustration of effects of skin vasodilation on preventricular volume sumps for right (RV) and left (LV) ventricles. As skin veins fill, venous return is transiently reduced so that preventricular sumps are depleted. Central or thoracic blood volume is represented by CBV.
Figure 25. Figure 25.

Skin vasoconstriction in response to lower‐body negative pressure (LBNP) in heat‐stressed human. Top panel shows when 5‐min periods of LBNP were applied before and after whole‐body skin temperature (Ts) was raised to increase body temperature (Tr, second panel) and increase forearm skin vascular conductance (FVC, bottom panel). Note arrow at 85 min and marked fall in mean arterial pressure (MAP, fourth panel). This subject could no longer elicit sufficient skin vasoconstriction to maintain MAP.

From Johnson, Rowell, et al. 236
Figure 26. Figure 26.

Regressions of forearm blood flow (FBF) vs. esophageal temperature (Tes) from a representative subject during supine rest (SR, open circles), supine exercise (SX, solid circles), upright rest (UR, open triangles), and upright exercise (UX, solid triangles). Under all conditions, skin temperature was held constant at 38°C to raise Tes and FBF during upright and supine rest. Note that, at any given Tes, upright rest and supine exercise decreased FBF below that at supine rest. Upright exercise caused the greatest decrease.

Adapted from Johnson, Rowell, and Brengelmann 239
Figure 27. Figure 27.

Response of total FBF in right and left arms (RFBF and LFBF) in 1 subject during 1 h of exercise at 750 kpm/min at 24°C ambient. Bottom panel from a separate experiment shows increase in FBF was confined to skin. Forearm muscle blood flow (MBF; 125I‐antipyrine clearance) fell during exercise.

Adapted from Johnson and Rowell 238
Figure 28. Figure 28.

Forearm blood flow (FBF) measured in left arm (solid circles) and right arm (open circles) during 60 min of prolonged exercise at 24°C ambient.

From Johnson and Rowell 238
Figure 29. Figure 29.

Forearm blood flow (FBF) vs. esophageal temperature (Tes) in 6 subjects during 17–30 min of moderate (86–147 W) upright exercise. Body skin temperature was maintained at 38°C throughout exercise. The 2 line segments in each panel are from linear regression analysis of data above and below Tes = 38°C.

From Brengelmann, Rowell, et al. 49
Figure 30. Figure 30.

Raising body skin temperature (Ts; top panel) abolishes forearm cutaneous venoconstrictor responses to exercise (at 3 min) and to local changes in arm Ts between 25°C and 40°C. Cycling body Ts (see bottom 3 panels) between 30°C and 37°C causes rapid changes in venous tone (pressure in occluded forearm veins) when local arm Ts is neutral. Note slow changes in venous tone when local arm Ts changed (11–14 min) while body Ts was 30°C.

From Rowell et al. 355
Figure 31. Figure 31.

Diagram of known inputs to cutaneous vasoconstrictor and vasodilator systems. The only factor known to influence the vasodilator system is changing Tc, but the vasoconstrictor system receives input from many receptors. The key unanswered question is whether these nonthermoregulatory reflexes also influence vasodilator outflow.
Figure 32. Figure 32.

Effects of upright posture and of upright exercise on pressure (and volume) in dependent veins. Exercise causes rapid venous emptying that restores CBV and CVP. Rapid emptying occurs during exercise in hot environments as well, but because of skin blood flow increases, veins refill so rapidly that average pressure (and volume) rises, resulting in reduced CBV and CVP.

Adapted from Henry and Gauer 214
Figure 33. Figure 33.

A: decrements in SBF versus percent of maximum O2 consumption () required during exercise in neutral (25.6°C) and a hot (43.3°C) environment. Heat stress reduced SBF at any given percent of (and at absolute as well). B: HR was increased at any given and percent of by heat stress, but the normal relationship between SBF and HR was unchanged (cf. Fig. 18).

From Rowell 340
Figure 34. Figure 34.

Summary of cardiovascular responses to graded exercise in hot (43.3°C, open triangles) and neutral (25.6°C, solid circles) environments. Arrows show direction of change in each variable. Cardiac output, CO; aortic mean pressure, AoMP; total peripheral resistance, TPR. Average data from 6 men.

Adapted from Rowell et al. 340
Figure 35. Figure 35.

Overall circulatory responses to rapid changes in skin temperature (Ts) (by water‐perfused suit) during upright exercise. Note reduction in Tra, SV, CBV, and RA MP (right atrial mean pressure) with sudden elevation of Ts at 30 and 90 min (some changes are more obvious at 90 min). Note sudden reversal of these effects when Ts was lowered at 60 min and stability of SV, Ao MP (MAP, aortic), and RA MP caused by keeping Ts low from 60 to 90 min.

Adapted from Rowell et al. 364
Figure 36. Figure 36.

Circulatory responses to prolonged mild (1 liter O2/min) upright exercise in 1 subject before (solid circles) and after (open triangles) 14 days of acclimatization to heat. On the 1st day the subject was severely stressed; HR reached 200 beats/min and Tre reached 40°C. Reductions in Tc, Ts, and HR and increase in SV (at same ) after acclimatization were striking.

Adapted from Rowell et al. 362
Figure 37. Figure 37.

Acclimatization (postheat) tends to shift relationship between FBF and Tes leftward. Physical training (pre‐ vs. postexercise) had no effect.

From Roberts et al. 330
Figure 38. Figure 38.

Dehydration (squares) markedly altered relationship between FBF and Tes so that SkBF was much lower at a given Tes. Note fall in SkBF above Tes of 38°C.

From Nadel et al. 302


Figure 1.

Comparison of simultaneous measurements of splanchnic blood flow (SBF) by constant‐dye‐infusion technique 44 and by electromagnetic flowmeters on hepatic artery and portal vein (solid and open circles) or by direct flow measurement (crosses) 106,266,384.

From Rowell 345, reproduced by permission of Grune & Stratton


Figure 2.

Simultaneous measurement of renal blood flow by p‐aminohippurate clearance (dashed line, left kidney) and electromagnetic flowmeter (solid line, right kidney) during graded hemorrhage, which lowered mean arterial pressure (MAP; top panel) and increased renal nerve activity (second panel).

Adapted from Selkurt 385


Figure 3.

Schematic illustration of blood volume distribution and venous pressures in upright human compared with those in the dog (and most other animals).

Adapted from Folkow and Neil 131


Figure 4.

Relationship between venous pressure in leg veins and volume of blood contained at 3 different leg skin temperatures (Tsk). Rise in local Tsk increases the blood volume contained in cutaneous veins at a given venous distending pressure; i.e., venous compliance increased.

Redrawn from Gauer and Thron 153; from Rowell 346


Figure 5.

Right and left forearm blood flows in 1 subject with congenital absence of sweat glands (anhidrotic ectodermal dysplasia) during direct whole‐body heating (forearms were not heated). Forearm blood flows showed almost no increase in response to a 1.5°C increase in Tc. In normal skin this would raise blood flow to 20–30 ml · min−1 · 100 ml−1 of forearm, the increment being confined to skin.

From Brengelmann, Rowell, et al. 48


Figure 6.

Cardiac output rose ∼6 liters/min, and forearm blood flow rose to 20 ml per 100 ml of forearm per min in 1 subject who was indirectly heated (legs in hot water) for 100 min, which raised body core temperature by 2.6°C. Heart rate, HR; stroke volume, SV.

From Koroxenidis et al. 263


Figure 7.

Circulatory responses to whole‐body heating to limits of thermal tolerance in a representative subject. Elevation in skin temperature (Ts) by water‐perfused suit raised rectal temperature (Tr) and right atrial blood temperature (Tb), cardiac output (CO), HR, SV, and central venous pressure (CVP). Note time courses of changes in aortic mean and pulse pressures (Ao BP) and right atrial mean pressure (RA‐MP). Total peripheral resistance, TPR.

From Rowell et al. 356


Figure 8.

Average circulatory responses in directly heated subjects. Initial and final values and approximate time course are shown for Ts and right atrial blood temperature (Tblood) and each cardiovascular variable. Changes in cardiac output and splanchnic, renal, and muscle blood flow contributing to increased skin blood flow are shown in separate boxes.

From Rowell 340


Figure 9.

Time course of changes in splanchnic blood flow (SBF) and splanchnic vascular resistance (SVR) (open triangles) during prolonged whole‐body heating (as in Figs. 7 and 8) in 7 subjects 352,358. Solid line in top panel, approximate time course of Tra (Tb) during heating.

From Rowell 340


Figure 10.

Left, estimated distribution of cardiac output between skin and other major organs at rest in normothermia; right, during severe hyperthermia (Tc greater than 39°C).



Figure 11.

Open bars, distribution of blood flow (radioactive microspheres) in 8 conscious baboons during quiet, seated rest in normothermic and hyperthermic (Tc increased 1.5°C‐2.0°C) conditions (cross‐hatching). Note insignificant rise in brain blood flow with heating. One SE and significance of change (*P < 0.05, **P < 0.01) are shown. Central nervous system, CNS.



Figure 12.

Blood flow (by microsphere technique) to various cutaneous regions during normothermic control period (solid bars) during moderate hyperthermia (Tc rose 1.5°C‐2.0°C) in resting, awake baboons (open bars, 0.5 SE shown where discernible).

From Hales, Rowell, and King 196


Figure 13.

Schematic illustration of altered distribution of blood volume in a heat‐stressed man. In contrast most species have small hydrostatic influence and small cutaneous vasodilation. Substantial vasodilation occurs in the dog tongue.



Figure 14.

Left, Krogh's 267 simplified model of the cardiovascular system divided into 2 circuits, 1 compliant (long time constant) and 1 noncompliant (short time constant). Right, electrical equivalent of a generalized parallel‐compartment model of the peripheral circulation. Arterial resistance, Ra; venous compliance, Cv; venous resistance, Rv (Rv2 and Cv2 illustrate variable resistance and compliance of cutaneous veins); arterial compliance, Ca. Venous time constant for a particular circuit (τ) is RvCv.

Left, adapted from Caldini et al. 67; right, adapted from Mitzner and Goldberg 298


Figure 15.

Hydraulic model contrasting effects of increasing blood flow through noncompliant (panel A) versus compliant circuits (panels B, C, D). Vasodilation of compliant circuits with long time constants (RvCv, in Fig. 14) depletes the volume (vol) of central reservoirs [central blood volume (CBV) or heart and pulmonary vessels]. Vasoconstriction (VC) of compliant circuits passively displaces their volumes to partially restore CBV.



Figure 16.

Schematic illustration of how volume may be mobilized passively from splanchnic veins as cutaneous veins fill up during heat stress. Fall in CVP creates a pressure gradient from right atrium to hepatic veins. Constriction of splanchnic arterioles further lowers splanchnic venous pressure and translocates more volume to the heart. Because of steep splanchnic venous pressure‐volume curve (right), a small decrease in venous pressure displaces a large volume of blood. GI, gastrointestinal tract.



Figure 17.

Relationship between heart rate and plasma norepinephrine concentration in cancer patients treated with hyperthermia (to 41.5°C).

From Kim et al. 249


Figure 18.

Relationship between SBF as percent of resting SBF and heart rate (HR) during exercise in neutral and hot environments 340 and before (open squares) and after (solid squares) physical conditioning 82. Data are compared with renal blood flow (RBF) during exercise 182. Regression lines for SBF versus HR in resting human stressed by heat and lower‐body negative pressure (LBNP) are displaced to the left (cf. norepinephrine data in Fig. 19) 340.

Adapted from Rowell 345


Figure 19.

Relationship between increase in plasma norepinephrine (NE; ng/ml) and change in HR during quiet standing (open and closed triangles) and during supine exercise (closed circles). Note the rightward displacement on HR axis during exercise (cf. Fig. 18).

Adapted from Christensen and Brandsborg 79


Figure 20.

Average responses to gradual decline in right atrial pressure (RAP) induced by slow ramp (‐1 mmHg/min) of lower‐body negative pressure (LBNP). Note that aortic mean pressure (MP), aortic pulse pressure (PP), and HR (and also aortic dP/dt, not shown) remained constant during the first 20 min of LBNP, whereas RAP fell to 0 mmHg, SBF decreased 10%, and FBF decreased by 35%. Results suggest that falling RAP, which unloaded cardiopulmonary stretch receptors, elicited regional vasoconstriction.

From Johnson, Rowell, et al. 240, by permission of the American Heart Association, Inc


Figure 21.

Relationship between percentage increase in splanchnic vascular resistance (δSVR %) and increase in plasma renin activity (APRA; ng of angiotensin I generated per 100 ml per 3 h) during prolonged whole‐body heating (as in Figs. 7 and 8; ref. 19).



Figure 22.

Results from 1 subject in whom body skin temperature (Ts) was driven in different temporal patterns to achieve periods of separation between changes in Ts (top panel) and central temperature [right atrial blood temperature (Tra.) and esophageal temperature (Tes); second panel]. Note close correspondence between rising Tra, sweat rate (SR), and forearm skin blood flow (FBF). Separate influences of Tra and T. on FBF, SR, and heart rate (HR) were determined mathematically. Influence of Tra on FBF was 20 times greater than that of Ts. per °C.

From Wyss, Rowell, et al. 466


Figure 23.

Results from 1 subject in whom body skin temperature (Ts) was controlled and driven in different patterns to reveal influences of body Ts, rate of change of Ts (, top panel), and central body temperature [esophageal temperature (Tes) and right atrial blood temperature (Tra)] on heart rate (HR), sweat rate (SR), and FBF. Note small effect of increasing Ts on FBF. Most increases in FBF and all the increase in SR attended increased Tra; Ts and had no influence on FBF when altered after elevation of Ts to 38°C for 30 min. Note also maintained high FBF long after SR had fallen. Central and cutaneous influences on FBF were determined by multiple linear regression for FBF, HR, and SR against Tra or Tes Ts, and during periods A, B, and C (top). In periods A and B, influence of Ts and on FBF was minimal.

From Wyss, Rowell, et al. 467


Figure 24.

Schematic illustration of effects of skin vasodilation on preventricular volume sumps for right (RV) and left (LV) ventricles. As skin veins fill, venous return is transiently reduced so that preventricular sumps are depleted. Central or thoracic blood volume is represented by CBV.



Figure 25.

Skin vasoconstriction in response to lower‐body negative pressure (LBNP) in heat‐stressed human. Top panel shows when 5‐min periods of LBNP were applied before and after whole‐body skin temperature (Ts) was raised to increase body temperature (Tr, second panel) and increase forearm skin vascular conductance (FVC, bottom panel). Note arrow at 85 min and marked fall in mean arterial pressure (MAP, fourth panel). This subject could no longer elicit sufficient skin vasoconstriction to maintain MAP.

From Johnson, Rowell, et al. 236


Figure 26.

Regressions of forearm blood flow (FBF) vs. esophageal temperature (Tes) from a representative subject during supine rest (SR, open circles), supine exercise (SX, solid circles), upright rest (UR, open triangles), and upright exercise (UX, solid triangles). Under all conditions, skin temperature was held constant at 38°C to raise Tes and FBF during upright and supine rest. Note that, at any given Tes, upright rest and supine exercise decreased FBF below that at supine rest. Upright exercise caused the greatest decrease.

Adapted from Johnson, Rowell, and Brengelmann 239


Figure 27.

Response of total FBF in right and left arms (RFBF and LFBF) in 1 subject during 1 h of exercise at 750 kpm/min at 24°C ambient. Bottom panel from a separate experiment shows increase in FBF was confined to skin. Forearm muscle blood flow (MBF; 125I‐antipyrine clearance) fell during exercise.

Adapted from Johnson and Rowell 238


Figure 28.

Forearm blood flow (FBF) measured in left arm (solid circles) and right arm (open circles) during 60 min of prolonged exercise at 24°C ambient.

From Johnson and Rowell 238


Figure 29.

Forearm blood flow (FBF) vs. esophageal temperature (Tes) in 6 subjects during 17–30 min of moderate (86–147 W) upright exercise. Body skin temperature was maintained at 38°C throughout exercise. The 2 line segments in each panel are from linear regression analysis of data above and below Tes = 38°C.

From Brengelmann, Rowell, et al. 49


Figure 30.

Raising body skin temperature (Ts; top panel) abolishes forearm cutaneous venoconstrictor responses to exercise (at 3 min) and to local changes in arm Ts between 25°C and 40°C. Cycling body Ts (see bottom 3 panels) between 30°C and 37°C causes rapid changes in venous tone (pressure in occluded forearm veins) when local arm Ts is neutral. Note slow changes in venous tone when local arm Ts changed (11–14 min) while body Ts was 30°C.

From Rowell et al. 355


Figure 31.

Diagram of known inputs to cutaneous vasoconstrictor and vasodilator systems. The only factor known to influence the vasodilator system is changing Tc, but the vasoconstrictor system receives input from many receptors. The key unanswered question is whether these nonthermoregulatory reflexes also influence vasodilator outflow.



Figure 32.

Effects of upright posture and of upright exercise on pressure (and volume) in dependent veins. Exercise causes rapid venous emptying that restores CBV and CVP. Rapid emptying occurs during exercise in hot environments as well, but because of skin blood flow increases, veins refill so rapidly that average pressure (and volume) rises, resulting in reduced CBV and CVP.

Adapted from Henry and Gauer 214


Figure 33.

A: decrements in SBF versus percent of maximum O2 consumption () required during exercise in neutral (25.6°C) and a hot (43.3°C) environment. Heat stress reduced SBF at any given percent of (and at absolute as well). B: HR was increased at any given and percent of by heat stress, but the normal relationship between SBF and HR was unchanged (cf. Fig. 18).

From Rowell 340


Figure 34.

Summary of cardiovascular responses to graded exercise in hot (43.3°C, open triangles) and neutral (25.6°C, solid circles) environments. Arrows show direction of change in each variable. Cardiac output, CO; aortic mean pressure, AoMP; total peripheral resistance, TPR. Average data from 6 men.

Adapted from Rowell et al. 340


Figure 35.

Overall circulatory responses to rapid changes in skin temperature (Ts) (by water‐perfused suit) during upright exercise. Note reduction in Tra, SV, CBV, and RA MP (right atrial mean pressure) with sudden elevation of Ts at 30 and 90 min (some changes are more obvious at 90 min). Note sudden reversal of these effects when Ts was lowered at 60 min and stability of SV, Ao MP (MAP, aortic), and RA MP caused by keeping Ts low from 60 to 90 min.

Adapted from Rowell et al. 364


Figure 36.

Circulatory responses to prolonged mild (1 liter O2/min) upright exercise in 1 subject before (solid circles) and after (open triangles) 14 days of acclimatization to heat. On the 1st day the subject was severely stressed; HR reached 200 beats/min and Tre reached 40°C. Reductions in Tc, Ts, and HR and increase in SV (at same ) after acclimatization were striking.

Adapted from Rowell et al. 362


Figure 37.

Acclimatization (postheat) tends to shift relationship between FBF and Tes leftward. Physical training (pre‐ vs. postexercise) had no effect.

From Roberts et al. 330


Figure 38.

Dehydration (squares) markedly altered relationship between FBF and Tes so that SkBF was much lower at a given Tes. Note fall in SkBF above Tes of 38°C.

From Nadel et al. 302
References
 1. Abramson, D. I. Circulation in the Extremities. New York: Academic, 1967, chapt. 11, p. 229–259.
 2. Abramson, N., T. E. Piemme, and W. C. Kaufman. Effect of heat stress upon human renal function. Aerosp. Med. 38: 234–238, 1967.
 3. Allwood, M. J., and G. P. Lewis. Bradykinin and forearm blood flow. J. Physiol. London 170: 571–581, 1964.
 4. Amberson, W. R. Physiologic adjustments to the standing posture. Bull. Univ. Md. Sch. Med. 27: 127–145, 1943.
 5. Ansari, A., and G. E. Burch. Influence of hot environments on the cardiovascular system. Arch. Intern. Med. 123: 371–378, 1969.
 6. Ardill, B. L., R. G. Bannister, P. H. Fentem, and A. D. M. Greenfield. Circulatory responses of supine subjects to the exposure of parts of the body below the xiphisternum to subatmospheric pressure. J. Physiol. London 193: 57–72, 1967.
 7. Ardill, B. L., V. M. Bhatnager, and P. Fentem. Observation of changes in volume of a congested limb as a means of studying the behaviour of capacity vessels. J. Physiol. London 194: 627–644, 1968.
 8. Aschoff, J. Circadian rhythm of activity and of body temperature. In: Physiological and Behavioral Temperature Regulation, edited by J. D. Hardy, A. P. Gagge, and J. A. J. Stolwijk. Springfield, IL: Thomas, 1970, chapt. 60, p. 905–919.
 9. Asmussen, E. The cardiac output in rest and work in humid heat. Am. J. Physiol. 131: 54–59, 1940.
 10. Asmussen, E. The distribution of the blood between the lower extremities and the rest of the body. Acta Physiol. Scand. 5: 31–38, 1943.
 11. Asmussen, E., and M. Nielsen. Cardiac output during muscular work and its regulation. Physiol. Rev. 35: 778–800, 1955.
 12. Åstrand, P.‐O., T. E. Cuddy, B. Saltin, and J. Stenberg. Cardiac output during submaximal and maximal work. J. Appl. Physiol. 19: 268–274, 1964.
 13. Avellini, B. A., E. Kamon, and J. T. Krajewski. Physiological responses of physically fit men and women to acclimation to humid heat. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 49: 254–261, 1980.
 14. Bailey, R. E., D. Bartos, F. Bartos, A. Castro, R. L. Dobson, D. P. Grettie, R. Kramer, D. MacFarlane, and K. Sato. Activation of aldosterone and renin secretion by thermal stress. Experientia 28: 159–160, 1972.
 15. Ballard, D. R., F. M. Abboud, and H. E. Mayer. Release of a humoral vasodilator substance during neurogenic vasodilatation. Am. J. Physiol. 219: 1451–1457, 1970.
 16. Barcroft, H. Sympathetic control of vessels in the hand and forearm skin. Physiol. Rev. 40, Suppl. 4: 81–91, 1960.
 17. Barcroft, H., K. D. Bock, H. Hensel, and A. H. Kitchin. Dis Muskeldurchblutung des Menchen bei indirekter Erwärmung und Abkühlung. Pfluegers Arch. Gesamte Physiol. Menschen Tiere 261: 199–210, 1955.
 18. Barcroft, H., and O. G. Edholm. The effect of temperature on blood flow and deep temperature in the human forearm. J. Physiol. London 102: 5–20, 1943.
 19. Barcroft, H., and O. G. Edholm. Temperature and blood flow in the human forearm. J. Physiol. London 104: 366–376, 1946.
 20. Barcroft, H., and A. Samaan. The explanation of the increase in systemic flow caused by occluding the descending thoracic aorta. J. Physiol. London 85: 47–61, 1935.
 21. Bass, D. E. Acclimatization to work in the heat. In: Temperature, Its Measurement and Control in Science and Industry, edited by J. M. Herzfeld. New York: Reinhold, 1963, vol. 3, pt. 3, p. 299–305.
 22. Bass, D. E., E. R. Buskirk, P. F. Iampietro, and M. Mager. Comparison of blood volume during physical conditioning, heat acclimatization and sedentary living. J. Appl. Physiol. 12: 186–188, 1958.
 23. Bass, D. E., and A. Henschel. Responses of body fluid compartments to heat and cold. Physiol. Rev. 36: 128–144, 1956.
 24. Bass, D. E., C. R. Kleeman, M. Quinn, A. Henschel, and A. H. Hegnauer. Mechanisms of acclimatization to heat in man. Medicine Baltimore 34: 323–380, 1955.
 25. Bazett, H. C. The regulation of body temperatures. In: Physiology of Heat Regulation and the Science of Clothing, edited by L. H. Newburgh. New York: Hafner, 1968, chapt. 4, p. 109–192.
 26. Behnke, A. R., and T. L. Willmon. Cutaneous diffusion of helium in relation to peripheral blood flow and the absorption of atmospheric nitrogen through the skin. Am. J. Physiol. 131: 627–632, 1940.
 27. Beiser, G. D., R. Zelis, S. E. Epstein, D. T. Mason, and E. Braunwald. The role of skin and muscle resistance vessels in reflexes mediated by the baroreceptor system. J. Clin. Invest. 49: 225–231, 1970.
 28. Bennett, T. D., and C. F. Rothe. Hepatic capacitance responses to changes in flow and hepatic venous pressure in dogs. Am. J. Physiol. 240 (Heart Circ. Physiol. 9): H18–H28, 1981.
 29. Benzinger, T. H. Heat regulation: homeostasis of central temperature in man. Physiol. Rev. 49: 671–759, 1969.
 30. Berlyne, G. M., J. P. M. Finberg, and C. Yoran. The effect of β‐adrenergic blockade on body temperature and plasma renin activity in heat‐exposed man. Br. J. Clin. Pharmacol. 1: 307–312, 1974.
 31. Bernard, C. Influence du grand sympathique sur la sensibilité et sur la calorification. C. R. Soc. Biol. Paris 3: 163–164, 1851.
 32. Claude Bernard and the vasomotor system. Quoted by H. H. Hoff and R. Guillermin. In: Claude Bernard and Experimental Medicine, edited by F. Grande and M. B. Visscher. Cambridge, UK: Schenkman, 1967.
 33. BevegÅrd, B. S., and J. T. Shepherd. Changes in tone of limb veins during supine exercise. J. Appl. Physiol. 20: 1–8, 1965.
 34. BevegÅrd, B. S., and J. T. Shepherd. Reaction in man of resistance and capacity vessels in forearm and hand to leg exercise. J. Appl. Physiol. 21: 123–132, 1966.
 35. BevegÅrd, B. S., and J. T. Shepherd. Regulation of the circulation during exercise in man. Physiol. Rev. 47: 178–213, 1967.
 36. BevegÅrd, S., J. Castenfors, and L. E. Lindblad. Effect of carotid sinus stimulation on cardiac output and peripheral vascular resistance during changes in blood volume distribution in man. Acta Physiol. Scand. 101: 50–57, 1977.
 37. BevegÅrd, S., J. Castenfors, L. E. Lindblad, and J. Tranesjö. Blood pressure and heart rate regulating capacity of the carotid sinus during changes in blood volume distribution in man. Acta Physiol. Scand. 99: 300–312, 1977.
 38. Bishop, J. M., K. W. Donald, S. H. Taylor, and P. N. Wormald. Changes in arterial‐hepatic venous O2 content difference during and after supine leg exercise. J. Physiol. London 137: 309–317, 1957.
 39. Blackmon, J. R., L. B. Rowell, J. W. Kennedy, R. D. Twiss, and R. D. Conn. Physiological significance of maximal oxygen intake in pure mitral stenosis. Circulation 36: 497–510, 1967.
 40. Blair, D. A., W. E. Glover, and I. C. Roddie. Vasomotor responses in the human arm during leg exercise. Circ. Res. 9: 264–274, 1961.
 41. Bloomfield, D. A. (editor). Dye Curves: The Theory and Practice of Indicator Dilution. Baltimore, MD: University Park, 1974.
 42. Bonde‐Petersen, F., L. B. Rowell, R. G. Murray, G. G. Blomqvist, R. White, E. Karlsson, W. Campbell, and J. H. Mitchell. Role of cardiac output in the pressor responses to graded muscle ischemia in man. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 45: 574–580, 1978.
 43. Bonner, R. M., M. H. Harrison, C. J. Hall, and R. J. Edwards. Effect of heat acclimatization on intravascular responses to acute heat stress in man. J. Appl. Physiol. 41: 708–713, 1976.
 44. Bradley, S. E. The hepatic circulation. In: Handbook of Physiology. Circulation, edited by W. F. Hamilton and P. Dow. Washington, DC: Am. Physiol. Soc. 1963, sect. 2, vol. II, chapt. 41, p. 1387–1438.
 45. Bradley, S. E., F. J. Ingelfinger, G. P. Bradley, and J. J. Curry. The estimation of hepatic blood flow in man. J. Clin. Invest. 24: 890–897, 1945.
 46. Bradley, T., L. A. Cochrane, J. A. Davies, R. J. Edwards, T. M. Gibson, M. J. Graveney, and M. H. Harrison. Some Electrolyte, Endocrine, and Blood Volume Responses to Heat Acclimation in Man. Farnborough, UK: Royal Air Force Institute of Aviation Medicine, IAM Rep. 583, 1980, p. 1–65.
 47. Brender, D., and M. Webb‐Peploe. Influence of carotid baroreceptors on different components of the vascular system. J. Physiol. London 205: 257–274, 1969.
 48. Brengelmann, G. L. Control of sweating rate and skin blood flow during exercise. In: Problems with Temperature Regulation During Exercise, edited by E. R. Nadel. New York: Academic, 1977, p. 27–48.
 49. Brengelmann, G. L., P. R. Freund, L. B. Rowell, J. E. Olerud, and K. K. Kraning. Absence of active cutaneous vasodilation associated with congenital absence of sweat glands in humans. Am. J. Phvsiol. 240 (Heart Circ. Physiol. 9): H571–H575, 1981.
 50. Brengelmann, G. L., J. M. Johnson, L. Hermansen, and L. B. Rowell. Altered control of skin blood flow during exercise at high internal temperatures. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 43: 790–794, 1977.
 51. Brengelmann, G. L., C. Wyss, and L. B. Rowell. Control of forearm skin blood flow during periods of steadily increasing skin temperature. J. Appl. Physiol. 35: 77–84, 1973.
 52. Brigden, W., S. Howarth, and E. P. Sharpey‐Schafer. Postural changes in the peripheral blood‐flow of normal subjects with observations on vasovagal fainting reactions as a result of tilting, the lordotic posture, pregnancy and spinal anesthesia. Clin. Sci. 9: 79–91, 1950.
 53. Bristow, J. D., E. B. Brown, Jr., D. J. C. Cunningham, M. G. Howson, E. Strange Petersen, T.‐G. Pickering, and P. Sleight. Effect of bicycling on the baroreflex regulation of pulse interval. Circ. Res. 28: 582–592, 1971.
 54. Brockelhurst, W. E., and I. J. Zeitlin. Determination of plasma kinin and kininogen levels in man. J. Physiol. London 191: 417–426, 1967.
 55. Brody, M. J. Histaminergic and cholinergic vasodilator systems. In: Mechanisms of Vasodilation, edited by P. M. Vanhoutte and I. Leusen. Basel: Karger, 1978, p. 266–277.
 56. Brooksby, G. A., and D. E. Donald. Dynamic changes in splanchnic blood flow and blood volume in dogs during activation of sympathetic nerves. Circ. Res. 29: 227–238, 1971.
 57. Brooksby, G. A., and D. E. Donald. Release of blood from the splanchnic circulation in dogs. Circ. Res. 31: 105–118, 1972.
 58. Brouha, L. Physiologic effect of work on the heart. In: The Heart in Industry, edited by L. J. Warshaw. New York: Hoeber, 1960, chapt. 2, p. 47–104.
 59. Brown, A. C., and G. L. Brengelmann. The interaction of peripheral and central inputs in the temperature regulation system. In: Physiological and Behavioral Temperature Regulation, edited by J. D. Hardy, A. P. Gagge, and J. A. J. Stolwijk. Springfield, IL: Thomas, 1970, chapt. 47, p. 684–702.
 60. Brown, E., J. S. Goei, A. D. M. Greenfield, and G. C. Plassaras. Circulatory responses to simulated gravitational shifts of blood in man induced by exposure of the body below the iliac crests to sub‐atmospheric pressure. J. Physiol. London 183: 607–627, 1966.
 61. Browse, N. L., R. R. Lorenz, and J. T. Shepherd. Response of capacity and resistance vessels of dog's limb to sympathetic nerve stimulation. Am. J. Physiol. 210: 95–102, 1966.
 62. Bullard, R. W. Studies on human sweat gland duct filling and skin hydration. J. Physiol. Paris 63: 218–221, 1971.
 63. Burke, D., G. Sundlöf, and B. G. Wallin. Postural effects on muscle nerve sympathetic activity in man. J. Physiol. London 272: 399–414, 1977.
 64. Burton, A. C. The application of the theory of heat flow to the study of energy metabolism. J. Nutr. 7: 497–533, 1934.
 65. Burton, A. C. Physiology and Biophysics of the Circulation. Chicago, IL: Year Book, 1965.
 66. Burton, A. C., and H. C. Bazett. A study of the average temperature of the tissues, of the exchanges of heat and vasomotor responses in man by means of a bath calorimeter. Am. J. Physiol. 117: 36–54, 1936.
 67. Cabanac, M. Temperature regulation. Annu. Rev. Physiol. 37: 415–439, 1975.
 68. Caldini, P., S. Permutt, J. A. Waddell, and R. L. Riley. Effect of epinephrine on pressure, flow, and volume relationships in the systemic circulation of dogs. Circ. Res. 34: 606–623, 1974.
 69. Calvelo, M. G., F. M. Abboud, D. R. Ballard, and W. Abdel‐Sayed. Reflex vascular responses to stimulation of chemoreceptors with nicotine and cyanide: activation of adrenergic constriction in muscle and noncholinergic dilation in dog's paw. Circ. Res. 27: 259–276, 1970.
 70. Cander, L., and R. E. Forster. Determination of pulmonary parenchymal tissue volume and pulmonary capillary blood flow in man. J. Appl. Physiol. 14: 541–551, 1959.
 71. Cannon, W. B. Bodily Changes in Pain, Hunger, Fear and Rage. New York: Appleton, 1915, p. 26–29.
 72. Castenfors, J. Renal clearances and urinary sodium and potassium excretion during supine exercise in normal subjects. Acta Physiol. Scand. 70: 207–214, 1967.
 73. Castenfors, J. Renal function during exercise. Acta Physiol. Scand. Suppl. 293: 7–244, 1967.
 74. Castenfors, J. Renal function during prolonged exercise. Ann. NY Acad. Sci. 301: 151–159, 1977.
 75. Challoner, A. V. J. Accurate measurement of skin blood flow by thermal conductance method. Med. Biol. Engl. 13: 196–201, 1975.
 76. Challoner, A. V. J. Photoelectric plethysmography for estimating cutaneous blood flow. In: Non‐Invasive Physiological Measurements, edited by P. Rolfe. London: Academic, 1979, p. 125–151.
 77. Chapman, C. B., A. Henschel, J. Minckler, A. Forsgren, and A. Keys. The effect of exercise on renal plasma flow in normal male subjects. J. Clin. Invest. 27: 639–644, 1948.
 78. Chimoskey, J. E. Skin blood flow by 133Xe disappearance validated by venous occlusion plethysmography. J. Appl. Physiol. 32: 432–435, 1972.
 79. Christensen, N. J. Plasma noradrenaline and adrenaline measured by isotope‐derivative assay. Dan. Med. Bull. 26: 17–56, 1979.
 80. Christensen, N. J., and O. Brandsborg. The relationship between plasma catecholamine concentration and pulse rate during exercise and standing. Eur. J. Clin. Invest. 3: 299–306, 1973.
 81. Christensen, N. J., H. Galbo, J. F. Hansen, B. Hesse, E. A. Richter, and J. Trap‐Jensen. Catecholamines and exercise. Diabetes 28, Suppl. 1: 58–62, 1979.
 82. Clausen, J. P. Effect of physical training on cardiovascular adjustments to exercise in man. Physiol. Rev. 57: 779–815, 1977.
 83. Clausen, J. P., K. Klausen, B. Rasmussen, and J. Trap‐Jensen. Central and peripheral circulatory changes after training of the arms or legs. Am. J. Physiol. 225: 675–682, 1973.
 84. Clausen, J. P., and J. Trap‐Jensen. Arteriohepatic venous oxygen difference and heart rate during initial phases of exercise. J. Appl. Physiol. 37: 716–719, 1974.
 85. Collins, G. M., and J. Ludbrook. Behavior of vascular beds in the human upper limb at low perfusion pressure. Circ. Res. 21: 319–325, 1967.
 86. Colman, R. W. Formation of human plasma kinin. N. Engl. J. Med. 291: 509–515, 1974.
 87. Conrad, M. C. Functional Anatomy of the Circulation to the Lower Extremities. Chicago, IL: Year Book, 1971.
 88. Conradt, M., R. Kullmann, T. Matsuzaki, and E. Simon. Arterial baroreceptor function in differential cardiovascular adjustments induced by central thermal stimulation. Basic Res. Cardiol. 70: 10–28, 1975.
 89. Convertino, V. A., L. C. Keil, E. M. Bernauer, and J. E. Greenleaf. Plasma volume, osmolality, vasopressin, and renin activity during graded exercise in man. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 50: 123–128, 1981.
 90. Cooper, K. E., O. G. Edholm, and R. F. Mottram. Blood flow in skin and muscle of the human forearm. J. Physiol. London 128: 258–267, 1955.
 91. Crossley, R. J., A. D. M. Greenfield, G. C. Plassaras, and D. Stephens. The interrelation of thermoregulatory and baroreceptor reflexes in the control of blood vessels in the human forearm. J. Physiol. London 183: 628–636, 1966.
 92. Culbertson, J. W., R. W. Wilkins, F. J. Ingelfinger, and S. E. Bradley. The effect of the upright posture upon hepatic blood flow in normotensive and hypertensive subjects. J. Clin. Invest. 30: 305–311, 1951.
 93. Cunningham, D. J. C., E. Strange Petersen, R. Peto, T. G. Pickering, and P. Sleight. Comparison of the effect of different types of exercise on the baroreflex regulation of heart rate. Acta Physiol. Scand. 86: 444–455, 1972.
 94. Dahn, I., and N. A. Lassen (editors). Proceedings of the symposium on clinical studies of peripheral circulation, Copenhagen, May 6‐7, 1966. Scand. J. Clin. Lab. Invest. Suppl. 99: 13–248, 1967.
 95. Dastre, A. F., and J. P. Morat. Influence du sang asphyxique sur l'appareil nerveux de la circulation. Arch. Physiol. Norm. Pathol. 3, Ser. 3: 1–45, 1884.
 96. Davies, C. T. M., C. Barnes, and A. J. Sargeant. Body temperature in exercise: effects of acclimatization to heat and habitation to work. Int. Z. Angew. Physiol. Einschl. Arbeits‐physiol. 30: 10–19, 1971.
 97. Davies, C. T. M., J. R. Brotherhood, J. D. Few, and E. Zeidi Fard. Effects of β‐blockade and atropinisation on plasma catecholamine concentration during exercise. Eur. J. Appl. Physiol. 36: 49–56, 1976.
 98. Davies, C. T. M., J. R. Brotherhood, and E. Zeidi Fard. Temperature regulation during severe exercise with some observations on effects of skin wetting. J. Appl. Physiol. 41: 772–776, 1976.
 99. Davies, C. T. M., J. R. Brotherhood, and E. Zeidi Fard. Effects of atropine and β‐blockade on temperature regulation and performance during prolonged exercise. Eur. J. Appl. Physiol. 38: 225–232, 1978.
 100. Delius, W., K.‐E. Hagbarth, A. Hongell, and B. G. Wallin. Manoeuvres affecting sympathetic outflow in human skin nerves. Acta Physiol. Scand. 84: 177–186, 1972.
 101. Detry, J.‐M. R., G. L. Brengelmann, L. B. Rowell, and C. Wyss. Skin and muscle components of forearm blood flow in directly heated resting man. J. Appl. Physiol. 32: 506–511, 1972.
 102. Detry, J.‐M. R., M. G. Gerin, A. A. Charlier, and L. A. Brasseur. Hemodynamic and thermal aspects of prolonged intermittent exercise. Int. Z. Angew. Physiol. Einschl. Arbeits‐physiol. 30: 171–185, 1972.
 103. Dill, D. B., and D. L. Costill. Calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration. J. Appl. Physiol. 37: 247–248, 1974.
 104. Doba, N., and D. J. Reis. Role of the cerebellum and the vestibular apparatus in regulation of orthostatic reflexes in the cat. Circ. Res. 34: 9–18, 1974.
 105. Donald, D. E., D. J. Rowlands, and D. A. Ferguson. Similarity of blood flow in the normal and the sympathectomized dog hindlimb during graded exercise. Circ. Res. 26: 185–199, 1970.
 106. Donegan, J. F. The physiology of the veins. J. Physiol. London 55: 226–245, 1921.
 107. Drapanas, T., D. N. Kluge, and W. G. Schenk, Jr. Measurement of hepatic blood flow by bromsulphalein and by the electromagnetic flowmeter. Surgery 48: 1017–1021, 1960.
 108. Drinkwater, B. L., J. E. Denton, I. C. Kupprat, T. S. Talag, and S. M. Horvath. Aerobic power as a factor in women's response to work in hot environments. J. Appl. Physiol. 41: 815–821, 1976.
 109. Ebert, R. V., and E. A. Stead, Jr. An error in measuring changes in plasma volume after exercise. Proc. Soc. Exp. Biol. Med. 46: 139–141, 1941.
 110. Echt, M., J. Düweling, O. H. Gauer, and L. Lange. Effective compliance of the total vascular bed and the intrathoracic compartment derived from changes in central venous pressure induced by volume changes in man. Circ. Res. 34: 61–68, 1974.
 111. Edholm, O. G., R. H. Fox, and R. K. MacPherson. The effect of body heating on the circulation in skin and muscle. J. Physiol. London 134: 612–619, 1956.
 112. Edholm, O. G., R. H. Fox, and R. K. MacPherson. Vasomotor control of the cutaneous blood vessels in the human forearm. J. Physiol. London 139: 455–465, 1957.
 113. Edwards, A. W. T., J. Isaacson, W. F. Sutterer, J. B. Bassingthwaighte, and E. H. Wood. Indocyanine green densitometry in flowing blood compensated for background dye. J. Appl. Physiol. 18: 1294–1304, 1963.
 114. Eichna, L. W., A. R. Berger, B. Rader, and W. H. Becker. Comparison of intracardiac and intravascular temperatures with rectal temperatures in man. J. Clin. Invest. 30: 353–359, 1951.
 115. Eichna, L. W., C. R. Park, N. Nelson, S. M. Horvath, and E. D. Palmes. Thermal regulation during acclimatization in a hot, dry (desert type) environment. Am. J. Physiol. 163: 585–597, 1950.
 116. Eisalo, A. Effects of the Finnish sauna on circulation. Studies on healthy and hypertensive subjects. Ann. Med. Exp. Biol. Fenniae 34, Suppl. 4: 7–96, 1956.
 117. Eisman, M. M., and L. B. Rowell. Renal vascular response to heat stress in baboons—role of renin‐angiotensin. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 43: 739–746, 1977.
 118. Ekelund, L.‐G. Circulatory and respiratory adaptation during prolonged exercise. Acta Physiol. Scand. Suppl. 292: 5–38, 1967.
 119. Eklund, B., and L. Kaijser. Blood flow in the resting forearm during prolonged contralateral isometric handgrip at maximal effort. J. Physiol. London 277: 359–366, 1978.
 120. Epstein, S. E., B. F. Robinson, R. L. Kahler, and E. Braunwald. Effects of beta‐adrenergic blockade on the cardiac response to maximal and submaximal exercise in man. J. Clin. Invest. 44: 1745–1753, 1965.
 121. Escourrou, P., P. R. Freund, L. B. Rowell, and D. G. Johnson. Splanchnic vasoconstriction in heat‐stressed man: role of renin‐angiotensin system. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 52 (6): 1438–1443, 1982.
 122. Esler, M., G. Jackman, A. Bobik, D. Kelleher, G. Jennings, P. Leonard, H. Skews, and P. Korner. Determination of norepinephrine apparent release rate and clearance in humans. Life Sci. 25: 1461–1470, 1979.
 123. Esler, M., G. Jackman, D. Kelleher, H. Skews, G. Jennings, A. Bobik, and P. Korner. Norepinephrine kinetics in patients with idiopathic autonomic insufficiency. Circ. Res. 46, Suppl. 1: 147–148, 1980.
 124. Esler, M., G. Jackman, P. Leonard, A. Bobik, H. Skews, G. Jennings, D. Kelleher, and P. Korner. Determination of noradrenaline uptake, spillover to plasma and plasma concentration in patients with essential hypertension. Clin. Sci. Suppl. 6: 311s–313s, 1980.
 125. Fein, J. T., E. M. Haymes, and E. R. Buskirk. Effects of daily and intermittent exposures on heat acclimation of women. Int. J. Biometeorol. 19: 41–52, 1975.
 126. Ferguson, R. J., J. A. Faulkner, S. Julius, and J. Conway. Comparison of cardiac output determined by CO2 rebreathing and dye‐dilution methods. J. Appl. Physiol. 25: 450–454, 1968.
 127. Finberg, J. P. M., and G. M. Berlyne. Modification of renin and aldosterone response to heat by acclimatization in man. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 42: 554–558, 1977.
 128. Finberg, J. P. M., Y. Kaplanski, and G. M. Berlyne. Renin and aldosterone secretion following heat exposure in man—relationship to Vo2 max and artificial acclimatization. Isr. J. Med. Sci. 12: 1530, 1976.
 129. Finberg, J. P. M., M. Katz, H. Gazit, and G. M. Berlyne. Plasma renin activity after acute heat exposure in nonacclimatized and naturally acclimatized man. J. Appl. Physiol. 36: 519–523, 1974.
 130. Fixler, D. E., J. M. Atkins, J. H. Mitchell, and L. D. Horowitz. Blood flow to respiratory, cardiac, and limb muscles in dogs during graded exercise. Am. J. Physiol. 231: 1515–1519, 1976.
 131. Folkow, B., C. Heymans, and E. Neil. Integrated aspects of cardiovascular regulation. In: Handbook of Physiology. Circulation, edited by W. F. Hamilton and P. Dow. Washington, DC: Am. Physiol. Soc. 1965, sect. 2, vol. III, chapt. 49, p. 1787–1823.
 132. Folkow, B., and E. Neil. Circulation. London: Oxford Univ. Press, 1971.
 133. Follenius, M., G. Brandenberger, B. Reinhardt, and M. Simeoni. Plasma aldosterone, renin activity, and Cortisol responses to heat exposure in sodium depleted and repleted subjects. Eur. J. Appl. Physiol. 41: 41–50, 1979.
 134. Fortney, S. M., E. R. Nadel, C. B. Wenger, and J. R. Bove. Effect of acute alterations of blood volume on circulatory performance in humans. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 50: 292–298, 1981.
 135. Fortney, S. M., and L. C. Senay, Jr. Effect of training and heat acclimation on exercise responses of sedentary females. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 47: 978–984, 1979.
 136. Fox, R. H., and O. G. Edholm. Nervous control of the cutaneous circulation. Br. Med. Bull. 19: 110–114, 1963.
 137. Fox, R. H., R. Goldsmith, D. J. Kidd, and H. E. Lewis. Acclimatization to heat in man by controlled elevation of body temperature. J. Physiol. London 166: 530–547, 1963.
 138. Fox, R. H., R. Goldsmith, D. J. Kidd, and H. E. Lewis. Blood flow and other thermoregulatory changes with acclimatization to heat. J. Physiol. London 166: 548–562, 1963.
 139. Fox, R. H., and S. M. Hilton. Bradykinin formation in human skin as a factor in heat vasodilatation. J. Physiol. London 142: 219–232, 1958.
 140. Fox, R. H., B. E. Löfstedt, P. M. Woodward, E. Eriksson, and B. Werkstrom. Comparison of thermoregulatory function in men and women. J. Appl. Physiol. 26: 444–453, 1969.
 141. Frayser, R., J. C. Ross, H. S. Levin, J. V. Messer, and J. Pines. Effect of increased environmental temperature on pulmonary diffusing capacity. J. Appl. Physiol. 21: 147–150, 1966.
 142. Frewin, D. B., D. J. McConnell, and J. A. Downey. Is a kininogenase necessary for human sweating? Lancet 2: 744, 1973.
 143. Frey, M. A. B., and R. A. Kenney. Cardiac response to whole‐body heating. Aviat. Space Environ. Med. 50: 387–389, 1979.
 144. Frye, A. J., and E. Kamon. Responses to dry heat of men and women with similar aerobic capacities. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 50: 65–70, 1981.
 145. Fuxe, K., and G. Sedvall. The distribution of adrenergic nerve fibers to the blood vessels in skeletal muscle. Acta Physiol. Scand. 64: 75–86, 1965.
 146. Galbo, H., J. J. Holst, and N. J. Christensen. Glucagon and plasma catecholamine responses to graded and prolonged exercise in man. J. Appl. Physiol. 38: 70–76, 1975.
 147. Galbo, H., J. J. Holst, N. J. Christensen, and J. Hilsted. Glucagon and plasma catecholamines during beta‐receptor blockade in exercising man. J. Appl. Physiol. 40: 855–863, 1976.
 148. Galbo, H., M. E. Houston, N. J. Christensen, J. J. Holst, B. Nielsen, E. Nygaard, and J. Suzuki. The effect of water temperature on the hormonal response to prolonged swimming. Acta Physiol. Scand. 105: 326–337, 1979.
 149. Gaskell, P. Are there sympathetic vasodilator nerves to the vessels of the hands? J. Physiol. London 131: 647–656, 1956.
 150. Gaskell, P., and A. C. Burton. Local postural vasomotor reflexes arising from the limb veins. Circ. Res. 1: 27–39, 1953.
 151. Gauer, O. H., and J. P. Henry. Neurohumoral control of plasma volume. In: Cardiovascular Physiology II, edited by A. C. Guyton and A. W. Cowley. Baltimore, MD: University Park, 1976, vol. 9, p. 145–190. (Int. Rev. Physiol. Ser.)
 152. Gauer, O. H., J. P. Henry, and H. O. Sieker. Changes in central venous pressure after moderate hemorrhage and transfusion in man. Circ. Res. 4: 79–84, 1956.
 153. Gauer, O. H., and H. L. Thron. Properties of veins in vivo: integrated effects of their smooth muscle. Physiol. Rev. 42, Suppl. 5: 283–303, 1962.
 154. Gauer, O. H., and H. L. Thron. Postural changes in the circulation. In: Handbook of Physiology. Circulation, edited by W. F. Hamilton and P. Dow. Washington, DC: Am. Physiol. Soc., 1965, sect. 2, vol. III, chapt. 67, p. 2409–2439.
 155. Gautvik, K. Studies on kinin formation in functional vasodilatation of the submandibular salivary gland in cats. Acta Physiol. Scand. 79: 174–187, 1970.
 156. Gautvik, K. The interaction of two different vasodilator mechanisms in the chorda‐tympani activated submandibular salivary gland. Acta Physiol. Scand. 79: 188–203, 1970.
 157. Gilbert, C. A., L. A. Bricker, W. T. Springfield, Jr., P. M. Stevens, and B. H. Warren. Sodium and water excretion and renal hemodynamics during lower body negative pressure. J. Appl. Physiol. 21: 1699–1704, 1966.
 158. Gisolfi, C. V. Work‐heat tolerance derived from interval training. J. Appl. Physiol. 35: 349–354, 1973.
 159. Gisolfi, C. V., and J. S. Cohen. Relationships among training, heat acclimation, and heat tolerance in men and women: the controversy revisited. Med. Sci. Sports 11: 56–59, 1979.
 160. Gisolfi, C., and S. Robinson. Relations between physical training, acclimatization, and heat tolerance. J. Appl. Physiol. 26: 530–534, 1969.
 161. Glaser, E. M. The effects of cooling and warming on the vital capacity, forearm and hand volume, and skin temperature of man. J. Physiol. London 109: 421–429, 1949.
 162. Glaser, E. M., F. R. Berridge, and K. M. Prior. Effects of heat and cold on the distribution of blood within the human body. Clin. Sci. 9: 181–187, 1950.
 163. Glover, W. E., A. D. M. Greenfield, B. S. L. Kidd, and R. F. Whelan. The reactions of the capacity blood vessels of the human hand and forearm to vaso‐active substances infused intra‐arterially. J. Physiol. London 140: 113–121, 1958.
 164. Göbel, D., H. Martin, and E. Simon. Primary cardiac responses to stimulation of hypothalamic and spinal core temperature sensors evaluated in anesthetized paralyzed dogs. J. Therm. Biol. 2: 4–47, 1977.
 165. Golenhofen, K. Blood flow of muscle and skin studied by the local heat clearance technique (Wärmeleitmessung). Scand. J. Clin. Lab. Invest. Suppl. 99: 79–85, 1967.
 166. Gorman, A. J., III. Thermoregulatory and Arterial Baroreflex Control of Heart Rate in the Heat‐Stressed Baboon. San Antonio: Univ. of Texas, 1980. Dissertation.
 167. Gorman, A. J., and D. W. Proppe. The autonomic control of heart rate in response to changes in arterial pressure in the normothermic and hyperthermic baboon. Federation Proc. 39: 960, 1980.
 168. Graf, W. Patterns of human liver temperature. Acta Physiol. Scand. Suppl. 160: 1–135, 1959.
 169. Grande, F., and H. L. Taylor. Adaptive changes in the heart, vessels, and patterns of control under chronically high loads. In: Handbook of Physiology. Circulation, edited by W. F. Hamilton and P. Dow. Washington, DC: Am. Physiol. Soc., 1965, sect. 2, vol. III, chapt. 74, p. 2615–2677.
 170. Grayson, J. Vascular reactions in the human intestine. J. Physiol. London 109: 439–447, 1949.
 171. Grayson, J. The measurement of intestinal blood flow in man. J. Physiol. London 114: 419–434, 1951.
 172. Green, J. F. Pressure‐flow and volume‐flow relationships of the systemic circulation of the dog. Am. J. Physiol. 229: 761–769, 1975.
 173. Green, J. F. Mechanism of action of isoproterenol on venous return. Am. J. Physiol. 232 (Heart Circ. Physiol. 1): H152–H156, 1977.
 174. Greenfield, A. D. M. The circulation through the skin. In: Handbook of Physiology. Circulation, edited by W. F. Hamilton and P. Dow. Washington, DC: Am. Physiol. Soc., 1963, sect. 2, vol. II, chapt. 39, p. 1325–1351.
 175. Greenfield, A. D. M., R. J. Whitney, and J. F. Mowbray. Methods for the investigation of peripheral blood flow. Br. Med. Bull. 19: 101–109, 1963.
 176. Greenleaf, J. E., V. A. Convertino, and G. R. Mangseth. Plasma volume during stress in man: osmolality and red cell volume. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 47: 1031–1038, 1979.
 177. Greenway, C. V., and R. D. Stark. Hepatic vascular bed. Physiol. Rev. 51: 23–65, 1971.
 178. Greenway, C. V., R. D. Stark, and W. W. Lautt. Capaci‐tance responses and fluid exchange in cat liver during stimulation of the hepatic nerves. Circ. Res. 25: 277–284, 1969.
 179. Greeson, T. P., R. I. Freedman, N. E. Levan, and W. H. Wong. Cutaneous vascular responses in diabetics. Microvasc. Res. 10: 8–16, 1975.
 180. Gregor, M., W. Jänig, and W. Riedel. Response pattern of cutaneous postganglionic neurones to the hindlimb on spinal cord heating and cooling in the cat. Pfluegers Arch. 363: 135–140, 1976.
 181. Grenvik, A. Errors of the dye dilution method compared to the direct Fick method of determination of cardiac output in man. Scand. J. Clin. Lab. Invest. 18: 486–492, 1966.
 182. Grimby, G. Renal clearances at rest and during physical exercise after injection of bacterial pyrogen. J. Appl. Physiol. 20: 137–141, 1965.
 183. Grimby, G. Renal clearances during prolonged supine exercise at different loads. J. Appl. Physiol. 20: 1294–1298, 1965.
 184. Guy, A. W., J. F. Lehmann, and J. B. Stonebridge. Therapeutic application of electromagnetic power. Proc. IEEE 62: 55–75, 1974.
 185. Hadjiminas, J., and B. Öberg. Effects of carotid baroreceptor reflexes on venous tone in skeletal muscle and intestine of the cat. Acta Physiol. Scand. 72: 518–532, 1968.
 186. Hagbarth, K.‐E., R. G. Hallin, A. Hongell, H. E. Torebjörk, and B. G. Wallin. General characteristics of sympathetic activity in human skin nerves. Acta Physiol. Scand. 84: 164–176, 1972.
 187. Hagen, R. D., F. J. Diaz, and S. M. Horvath. Plasma volume changes with movement to supine and standing positions. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 45: 414–418, 1978.
 188. Häggendal, J., L. H. Hartley, and B. Saltin. Arterial noradrenaline concentration during exercise in relation to the relative work levels. Scand. J. Clin. Lab. Invest. 26: 337–342, 1970.
 189. Hainsworth, R., and R. J. Linden. Reflex control of vascular capacitance. In: Cardiovascular Physiology III, edited by A. C. Guyton and D. B. Young. Baltimore, MD: University Park, 1979, vol. 18, p. 67–124. (Int. Rev. Physiol. Ser.)
 190. Hales, J. R. S. Effects of exposure to hot environments on the regional distribution of blood flow and on cardiorespiratory function in sheep. Pfluegers Arch. 344: 133–148, 1973.
 191. Hales, J. R. S. Physiological responses to heat. In: Environmental Physiology I, edited by D. Robertshaw. Baltimore, MD: University Park, 1974, vol. 7, p. 107–162. (Int. Rev. Physiol. Ser.)
 192. Hales, J. R. S., J. W. Bennett, and A. A. Fawcett. Hypothalamic temperature influences on regional tissue blood flow. Proc. Aust. Physiol. Pharmacol. Soc. 6: 142–143, 1975.
 193. Hales, J. R. S., J. W. Bennett, and A. A. Fawcett. Integrated changes in regional circulatory activity evoked by thermal stimulation of the hypothalamus. Pfluegers Arch. 372: 157–164, 1977.
 194. Hales, J. R. S., and R. A. L. Dampney. The redistribution of cardiac output in the dog during heat stress. J. Therm. Biol. 1: 29–34, 1975.
 195. Hales, J. R. S., A. A. Fawcett, and J. W. Bennett. Differential influences of CNS and superficial body temperatures on the partition of cutaneous blood flow between capillaries and arteriovenous anastomoses (AVA's). Pfluegers Arch. 361: 105–106, 1975.
 196. Hales, J. R. S., and M. Iriki. Integrated changes in regional circulatory activity evoked by spinal cord and peripheral thermoreceptor stimulation. Brain Res. 87: 267–279, 1975.
 197. Hales, J. R. S., L. B. Rowell, and R. B. King. Regional distribution of blood flow in awake heat‐stressed baboons. Am. J. Physiol. 237 (Heart Circ. Physiol. 6): H705–H712, 1979.
 198. Hales, J. R. S., L. B. Rowell, and D. E. Strandness, Jr. Active cutaneous vasodilatation in the hyperthermic baboon. Proc. Aust. Physiol. Pharmacol. Soc. 8: 70P, 1977.
 199. Hallin, R. G., and H. E. Torebjörk. Single unit sympathetic activity in human skin nerves during rest and various manoeuvres. Acta Physiol. Scand. 92: 303–317, 1974.
 200. Hanke, D., M. Schlepper, K. Westermann, and E. Witzleb. Venentonus, Haut‐ und Muskeldurchblutung an Unterarm und Hand bei Beinarbeit. Pfluegers Arch. 309: 115–127, 1969.
 201. Hansen, J. F., N. J. Christensen, and B. Hesse. Determinants of coronary sinus noradrenaline in patients with ischaemic heart disease: coronary sinus catecholamine concentration in relation to arterial catecholamine concentration, pulmonary artery oxygen saturation and left ventricular end‐diastolic pressure. Cardiovasc. Res. 12: 415–421, 1978.
 202. Hansen, J. F., B. Hesse, and N. J. Christensen. Enhanced sympathetic nervous activity after intravenous propranolol in ischaemic heart disease: plasma noradrenaline splanchnic blood flow and mixed venous oxygen saturation at rest and during exercise. Eur. J. Clin. Invest. 8: 31–36, 1978.
 203. Harrison, M. H. Plasma volume changes during acute exposure to a high environmental temperature. J. Appl. Physiol. 37: 38–42, 1974.
 204. Harrison, M. H., R. J. Edwards, and P. A. Fennessy. Intravascular volume and tonicity as factors in the regulation of body temperature. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 44: 69–75, 1978.
 205. Harrison, M. H., R. J. Edwards, and D. R. Leitch. Effect of exercise and thermal stress on plasma volume. J. Appl. Physiol. 39: 925–931, 1975.
 206. Hayward, J. N., and M. A. Baker. A comparative study of the role of the cerebral arterial blood in the regulation of brain temperature in five mammals. Brain Res. 16: 417–440, 1969.
 207. Heistad, D. D., F. M. Abboud, A. L. Mark, and P. G. Schmid. Interaction of thermal and baroreceptor reflexes in man. J. Appl. Physiol. 35: 581–586, 1973.
 208. Hellon, R. F. Local effects of temperature. Br. Med. Bull. 19: 141–144, 1963.
 209. Hellon, R. F., and A. R. Lind. Circulation in the hand and forearm with repeated daily exposures to humid heat. J. Physiol. London 128: 57P, 1955.
 210. Hellon, R. F., and A. R. Lind. Sweating and vasodilation in the human forearm. J. Physiol. London 134: 18P, 1956.
 211. Hénane, R., and J. Bittel. Changes of thermal balance induced by passive heating in resting man. J. Appl. Physiol. 38: 294–299, 1975.
 212. Hénane, R., and J. L. Valaty. Thermoregulatory changes induced during heat acclimatization by controlled hyperthermia in man. J. Physiol. London 230: 255–271, 1973.
 213. Henriksen, O. Local sympathetic reflex mechanism in regulation of blood flow in human subcutaneous adipose tissue. Acta Physiol. Scand. 101, Suppl. 450: 1–48, 1977.
 214. Henry, J. P. The significance of the loss of blood volume into the limbs during pressure breathing. Aviat. Med. 22: 31–38, 1951.
 215. Henry, J. P., and O. H. Gauer. The influence of temperature upon venous pressure in the foot. J. Clin. Invest. 29: 855–861, 1950.
 216. Hertzman, A. B. The blood supply of various skin areas as estimated by the photoelectric plethysmograph. Am. J. Physiol. 124: 328–340, 1938.
 217. Hertzman, A. B. Vasomotor regulation of the cutaneous circulation. Physiol. Rev. 39: 280–306, 1959.
 218. Hesse, B., E. D. Andersen, and H. Ring‐Larsen. Hepatic elimination of renin in man. Clin. Sci. Mol. Med. 55: 377–382, 1978.
 219. Hesse, B., H. Ring‐Larsen, I. Nielsen, and N. J. Christensen. Renin stimulation by passive tilting: the influence of an anti‐gravity suit on postural changes in plasma renin activity, plasma noradrenaline concentration and kidney function in normal man. Scand. J. Clin. Lab. Invest. 38: 163–169, 1978.
 220. Hilton, S. M., and G. P. Lewis. The cause of the vasodilatation accompanying activity in the submandibular salivary gland. J. Physiol. London 128: 235–248, 1955.
 221. Holloway, G. A. Cutaneous blood flow response to injection trauma measured by laser doppler velocimetry. J. Invest. Dermatol. 74: 1–4, 1980.
 222. Holloway, G. A., and D. W. Watkins. Laser doppler measurement of cutaneous blood flow. J. Invest. Dermatol. 69: 306–309, 1977.
 223. Hultman, E. Blood circulation in the liver under physiological and pathological conditions. Scand. J. Clin. Lab. Invest. 18, Suppl. 92: 27–41, 1966.
 224. Imai, Y., K. Satoh, and N. Taira. Role of the peripheral vasculature in changes in venous return caused by isoproterenol, norepinephrine, and methoxamine in anesthetized dogs. Circ. Res. 43: 553–561, 1978.
 225. Iriki, M., W. Riedel, and E. Simon. Regional differentiation of sympathetic activity during hypothalamic heating and cooling in anesthetized rabbits. Pfluegers Arch. 328: 320–331, 1971.
 226. Iriki, M., W. Riedel, and E. Simon. Patterns of differentiation in various sympathetic efferents induced by changes of blood gas composition and by central thermal stimulation in anesthetized rabbits. Jpn. J. Physiol. 22: 585–602, 1972.
 227. Iriki, M., and E. Simon. Differential autonomic control of regional circulatory reflexes evoked by thermal stimulation and by hypoxia. Aust. J. Exp. Biol. Med. Sci. 51: 283–293, 1973.
 228. Iriki, M., and E. Simon. Regional differentiation of sympathetic efferents. In: Integrative Control Functions of the Brain, edited by M. Ito, N. Tsukahara, K. Kubota, and K. Yagi. Amsterdam: Elsevier, 1978, vol. 1, p. 221–238.
 229. Jessen, C., and E. T. Mayer. Spinal cord and hypothalamus as core sensors of temperature in the conscious dog. Pfluegers Arch. 324: 189–204, 1971.
 230. Jessen, C., and E. Simon. Spinal cord and hypothalamus as core sensors of temperature in the conscious dog. III. Identity of functions. Pfluegers Arch. 324: 217–226, 1971.
 231. Johansen, J. E. Ueber die Einwirkung der Muskelthatigkeit auf die Athmung und die Herzthatigkeit. Scand. Arch. Physiol. 5: 20–66, 1895.
 232. Johansen, K. Heat exchange through the muskrat tail. Evidence for vasodilator nerves to the skin. Acta Physiol. Scand. 55: 160–169, 1962.
 233. Johnson, D. G., J. S. Hayward, T. P. Jacobs, M. L. Collis, J. D. Eckerson, and R. H. Williams. Plasma norepinephrine responses of man in cold water. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 43: 216–220, 1977.
 234. Johnson, J. M. Regulation of skin circulation during prolonged exercise. Ann. NY Acad. Sci. 301: 195–212, 1977.
 235. Johnson, J. M. Responses of forearm blood flow to graded leg exercise in man. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 46: 457–462, 1979.
 236. Johnson, J. M., G. L. Brengelmann, and L. B. Rowell. Interactions between local and reflex influences on human forearm skin blood flow. J. Appl. Physiol. 41: 826–831, 1976.
 237. Johnson, J. M., M. Niederberger, L. B. Rowell, M. M. Eisman, and G. L. Brengelmann. Competitition between cutaneous vasodilator and vasoconstrictor reflexes in man. J. Appl. Physiol. 35: 798–803, 1973.
 238. Johnson, J. M., and M. K. Park. Reflex control of skin blood flow by skin temperature: role of core temperature. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 47: 1188–1193, 1979.
 239. Johnson, J. M., and L. B. Rowell. Forearm skin and muscle vascular responses to prolonged leg exercise in man. J. Appl. Physiol. 39: 920–924, 1975.
 240. Johnson, J. M., L. B. Rowell, and G. L. Brengelmann. Modification of the skin blood flow‐body temperature relationship by upright exercise. J. Appl. Physiol. 37: 880–886, 1974.
 241. Johnson, J. M., L. B. Rowell, M. Niederberger, and M. M. Eisman. Human splanchnic and forearm vasoconstrictor responses to reductions of right atrial and aortic pressure. Circ. Res. 34: 515–524, 1974.
 242. Johnson, R. H., and J. M. K. Spalding. Disorders of the Autonomic Nervous System. Philadelphia, PA: Davis, 1974.
 243. Jorfeldt, L., A. Juhlin‐Dannfelt, B. Pernow, and R. Wassen. Determination of human leg blood flow: a thermodilution technique based on femoral venous bolus injection. Clin. Sci. Mol. Med. 54: 512–523, 1978.
 244. Jorfeldt, L., and J. Wahren. Leg blood flow during exercise in man. Clin. Sci. 41: 459–473, 1971.
 245. Jorgensen, C. R., F. L. Gobel, H. L. Taylor, and Y. Wang. Myocardial blood flow and oxygen consumption during exercise. Ann. NY Acad. Sci. 301: 213–223, 1977.
 246. Kaufmann, W. Die Regulation des Herzzeitvolumens bei thermischen Belastungen in der Klimakammer. Arch. Phys. Ther. Leipzig 12: 175–184, 1960.
 247. Kaufmann, W., H. Nieth, and J. G. Schlitter. Wasser‐Electrolyte‐Elimination und renale Hämodynamik bei Erhöhung der Umgebungstemperatur. Pfluegers Arch. 272: 31–32, 1960.
 248. Kenney, R. A. The effect of hot, humid environments on the renal function of West Africans. J. Physiol. London 118: 25P–26P, 1952.
 249. Kidd, B. S. L., and S. M. Lyons. The distensibility of the blood vessels of the human calf determined by graded venous congestion. J. Physiol. London 140: 122–128, 1958.
 250. Kim, Y. D., C. R. Lake, D. E. Lees, W. H. Schuette, J. M. Bule, V. Weise, and I. J. Kopin. Hemodynamic and plasma catecholamine responses to hyperthermic cancer therapy in humans. Am. J. Physiol. 237 (Heart Circ. Physiol. 6): H570–H574, 1979.
 251. Kiowski, W., and S. Julius. Renin response to stimulation of cardiopulmonary mechanoreceptors in man. J. Clin. Invest. 62: 656–663, 1978.
 252. Kirchheim, H. R. Systemic arterial baroreceptor reflexes. Physiol. Rev. 56: 100–176, 1976.
 253. Kirsch, K. A., J. Merke, H. Hinghofer‐Szalkay, M. Barnkow, and H. J. Wicke. A new miniature plethysmograph to measure volume changes in small circumscribed tissue areas. Pfluegers Arch. 383: 189–194, 1980.
 254. Kirsch, K., W.‐D. Risch, U. Mund, L. Röcker, and H. Stoboy. Low pressure system and blood volume regulating hormones after prolonged exercise. In: Metabolic Adaptation to Prolonged Physical Exercise, edited by H. Howald and J. R. Poortmans. Basel: Birkhäusen, 1975, p. 315–321.
 255. Kirsch, K., G. Schultze, L. Röcker, U. Bierbaum, and P. Eckert. The effect of exercise and dehydration on plasma volume and central venous pressure. Z. Kardiol. 62: 49–58, 1973.
 256. Kitamura, K., C. R. Jorgensen, F. L. Gobel, H. L. Taylor, and Y. Wang. Hemodynamic correlates of myocardial oxygen consumption during upright exercise. J. Appl. Physiol. 32: 516–522, 1972.
 257. Klocke, R. A., G. H. Gurnter, and L. E. Farhi. Gas transfer across the skin in man. J. Appl. Physiol. 18: 311–316, 1963.
 258. Koizumi, K., H. Seller, A. Kaufman, and C. McC. Brooks. Pattern of sympathetic discharges and their relation to baroreceptor and respiration activities. Brain Res. 27: 281–294, 1971.
 259. Kontos, H. A., D. W. Richardson, and J. L. Patterson, Jr. Blood flow and metabolism of forearm muscle in man at rest and during sustained contraction. Am. J. Physiol. 211: 869–876, 1966.
 260. Kopin, I. J., R. C. Lake, and M. Ziegler. Plasma levels of norepinephrine. Ann. Int. Med. 88: 671–680, 1978.
 261. Korner, P. I. Integrative neural cardiovascular control. Physiol. Rev. 51: 312–367, 1971.
 262. Korner, P. I. Control of blood flow to special vascular areas: brain, kidney, muscle, skin, liver, and intestine. In: Cardiovascular Physiology I, edited by A. C. Guyton and C. E. Jones. Baltimore, MD: University Park, 1974, vol. 1, p. 123–162. (Int. Rev. Physiol. Ser.)
 263. Korner, P. I. Central nervous control of autonomic cardiovascular function. In: Handbook of Physiology. The Cardiovascular System. The Heart, edited by R. M. Berne and N. Sperelakis. Bethesda, MD: Am. Physiol. Soc., 1979, sect. 2, vol. 1, chapt. 20, p. 691–739.
 264. Koroxenidis, G. T., J. T. Shepherd, and R. J. Marshall. Cardiovascular response to acute heat stress. J. Appl. Physiol. 16: 869–872, 1961.
 265. Kosunen, K. J., A. J. Pakarinen, K. Kuoppasalmi, and H. Aldercreutz. Plasma renin activity, angiotensin II and aldosterone during intense heat stress. J. Appl. Physiol. 41: 323–327, 1976.
 266. Kotchen, T. A., L. H. Hartley, T. W. Rice, E. H. Mougey, L. G. Jones, and J. W. Mason. Renin, norepinephrine, and epinephrine responses to graded exercise. J. Appl. Physiol. 31: 178–184, 1971.
 267. Krarup, N. The effect of noradrenaline and adrenaline on hepatosplanchnic hemodynamics, functional capacity of the liver and hepatic metabolism. Acta Physiol. Scand. 87: 307–319, 1973.
 268. Krogh, A. The regulation of the supply of blood to the right heart. Scand. Arch. Physiol. 27: 227–248, 1912.
 269. Kullmann, R., W. Schönung, and E. Simon. Antagonistic changes of blood flow and sympathetic activity in different vascular beds following central thermal stimulation. I. Blood flow in skin, muscle, and intestine during spinal cord heating and cooling in anesthetized dogs. Pfluegers Arch. 319: 146–161, 1970.
 270. Lang, W. J., C. Bell, E. L. Conway, and R. Padanyi. Cutaneous and muscular vasodilation in the canine hindlimb evoked by central stimulation. Circ. Res. 38: 560–566, 1976.
 271. Lautt, W. W., and C. V. Greenway. Hepatic venous compliance and role of liver as a blood reservoir. Am. J. Physiol. 231: 292–295, 1976.
 272. Leithead, C. S., and A. R. Lind. Heat Stress and Heat Disorders. Philadelphia, PA: Davis, 1964.
 273. Levy, B., A. Ghaem, J. M. Verpillat, and J. P. Martineaud. Antagonistic effects upon cutaneous circulation of muscular exercise and exposure to a high ambient temperature. Pfluegers Arch. 359: 137–146, 1975.
 274. Lind, A. R., and D. Bass. Optimal exposure time for development of acclimatization to heat. Federation Proc. 22: 704–708, 1963.
 275. Lind, A. R., C. S. Leithead, and G. W. McNicol. Cardiovascular changes during syncope induced by tilting men in the heat. J. Appl. Physiol. 25: 268–276, 1968.
 276. Longhurst, J. C., and J. H. Mitchell. Reflex control of the circulation by afferents from skeletal muscle. In: Cardiovascular Physiology III, edited by A. C. Guyton and D. B. Young. Baltimore, MD: University Park, 1979, vol. 18, p. 125–148. (Int. Rev. Physiol. Ser.)
 277. Love, A. G. H., and R. G. Shanks. The relationship between the onset of sweating and vasodilatation in the forearm during body heating. J. Physiol. London 162: 121–128, 1962.
 278. Ludbrook, J. Aspects of Venous Function in the Lower Limbs. Springfield, IL: Thomas, 1966.
 279. Ludbrook, J., I. B. Faris, J. Iannos, G. G. Jamieson, and W. J. Russell. Lack of effect of isometric handgrip exercise on the responses of the carotid sinus baroreceptor reflex in man. Clin. Sci. Mol. Med. 55: 189–194, 1978.
 280. Lundbergh, P. Hepatic circulation in hepatitis A. Acta Med. Scand. Suppl. 562: 7–48, 1974.
 281. Lutz, J., U. Peiper, J. Segarra‐Domenech, and E. Bauerreisen. Das Druck‐Volumendiagram und Elastizitätswerte des gesampten Lerbergefassystems der Katze in situ. Pfluegers Arch. 295: 315–327, 1967.
 282. Luurila, O. J. Arrhythmias and other cardiovascular responses during Finnish sauna and exercise testing in healthy men and post‐myocardial infarction patients. Acta. Med. Scand. Suppl. 641: 7–60, 1980.
 283. Maher, J. T., D. E. Bass, D. D. Heistad, E. T. Angelakos, and L. H. Hartley. Effect of posture on heat acclimatization in man. J. Appl. Physiol. 33: 8–13, 1972.
 284. Mancia, G., J. Iannos, G. G. Jamieson, R. H. Lawrence, P. R. Sharman, and J. Ludbrook. Effect of isometric hand‐grip exercise on the carotid sinus baroreceptor reflex in man. Clin. Sci. Mol. Med. 54: 33–37, 1978.
 285. Manhem, P., H. Lecerof, and B. Hökfelt. Plasma catecholamine levels in the coronary sinus, the left renal vein and peripheral vessels in healthy males at rest and during exercise. Acta Physiol. Scand. 104: 364–369, 1978.
 286. Mark, A. L., F. M. Abboud, and A. E. Fitz. Influence of low‐and high‐pressure baroreceptors on plasma renin activity in humans. Am. J. Physiol. 235 (Heart Circ. Physiol. 4): H29–H33, 1978.
 287. Marshall, R. J., and J. T. Shepherd. Interpretation of changes in “central” blood volume and slope volume during exercise in man. J. Clin. Invest. 40: 375–385, 1961.
 288. Marshall, R. J., and J. T. Shepherd. Cardiac Function in Health and Disease. Philadelphia, PA: Saunders, 1968, chapt. 2, p. 31–65.
 289. Martin, H., D. Göbel, and E. Simon. Vasodilator vs. vasoconstrictor responses in the skin to cooling hypothalamus of anesthetized dogs. J. Therm. Biol. 2: 49–52, 1977.
 290. Marx, H. J., L. B. Rowell, R. D. Conn, R. A. Bruce, and F. Kusumi. Maintenance of aortic pressure and total peripheral resistance during exercise in heat. J. Appl. Physiol. 22: 519–525, 1967.
 291. McCook, R. D., R. D. Wurster, and W. C. Randall. Sudomotor and vasomotor responses to changing environmental temperature. J. Appl. Physiol. 20: 371–383, 1965.
 292. McGirr, E. M. The rate of removal of radioactive sodium following its injection into muscle and skin. Clin. Sci. 11: 91–99, 1952.
 293. McIntosh, H. D., W. L. Gleason, D. E. Miller, and J. M. Bacos. A major pitfall in the interpretation of “central blood volume.” Circ. Res. 9: 1223–1228, 1961.
 294. McNamara, H. I., J. M. Sikorski, and H. Clavin. The effects of lower body negative pressure on hand blood flow. Cardiovasc. Res. 3: 284–291, 1969.
 295. Mellander, S. Comparative studies on the adrenergic neurohormonal control of resistance and capacitance blood vessels in the cat. Acta Physiol. Scand. 50, Suppl. 176: 1–86, 1960.
 296. Mellander, S., and B. Johansson. Control of resistance, exchange and capacitance functions in the peripheral circulation. Pharmacol. Rev. 20: 117–196, 1968.
 297. Mense, S. Muscular nociceptors. J. Physiol. Paris 73: 233–240, 1977.
 298. Mitchell, D., L. C. Senay, C. H. Wyndham, A. J. van Rensberg, G. G. Rogers, and N. B. Strydom. Acclimatization in a hot, humid environment: energy exchange, body temperature, and sweating. J. Appl. Physiol. 40: 768–778, 1976.
 299. Mitzner, W., and H. Goldberg. Effects of epinephrine on resistive and compliant properties of the canine vasculature. J. Appl. Physiol. 39: 272–280, 1975.
 300. Mosley, J. G. A reduction in some vasodilator responses in freestanding man. Cardiovasc. Res. 3: 14–21, 1969.
 301. Müller, O. Über die Blutverteilung in menschlichen Körper unter dem Einfluss thermischer Reize. Arch. Klin. Med. 82: 547–585, 1905.
 302. Nadel, E. R., E. Cafarelli, M. F. Roberts, and C. B. Wenger. Circulatory regulation during exercise in different ambient temperatures. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 46: 430–437, 1979.
 303. Nadel, E. R., S. M. Fortney, and C. B. Wenger. Effect of hydration state on circulatory and thermal regulations. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 49: 715–721, 1980.
 304. Nadel, E. R., K. B. Pandolf, M. F. Roberts, and J. A. J. Stolwijk. Mechanisms of thermal acclimation to exercise and heat. J. Appl. Physiol. 37: 515–520, 1974.
 305. Nielsen, B. Thermoregulation in rest and exercise. Acta Physiol. Scand. Suppl. 323: 13–74, 1969.
 306. Nielsen, B. Thermoregulation during work in carbon monoxide poisoning. Acta Physiol. Scand. 82: 98–106, 1971.
 307. Neilsen, B. Physical effort and thermoregulation in man. Isr. J. Med. Sci. 12: 974–981, 1974.
 308. Neilsen, M., L. P. Herrington, and C.‐E. A. Winslow. The effect of posture on peripheral circulation. Am. J. Physiol. 127: 573–580, 1939.
 309. Nilsson, G. E., T. Tenland, and P. Å. Öberg. A new instrument for continuous measurement of tissue blood flow by light beating spectroscopy. IEEE Trans. Biomed. Eng. BME‐27: 12–19, 1980.
 310. Ninomiya, I., and S. Fujita. Reflex effects of thermal stimulation on sympathetic nerve activity to skin and kidney. Am. J. Physiol. 230: 271–278, 1976.
 311. Ninomiya, I., N. Nisimaru, and H. Irisawa. Sympathetic nerve activity to the spleen, kidney, and heart in response to baroreceptor input. Am. J. Physiol. 221: 1346–1351, 1971.
 312. Nixon, J. V., R. G. Murray, C. Bryant, R. L. Johnson, Jr., J. H. Mitchell, O. B. Holland, C. Gomez‐Sanchez, P. Vergne‐Marini, and C. G. Blomqvist. Early cardiovascular adaptation to simulated zero gravity. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 46: 541–548, 1979.
 313. Nunnely, S. A. Physiological responses of women to thermal stress: a review. Med. Sci. Sports 10: 250–255, 1978.
 314. O'Donnell, T. F., Jr. The hemodynamic and metabolic alterations associated with acute heat stress injury in marathon runners. Ann. NY Acad. Sci. 301: 262–269, 1977.
 315. Ogilvie, R. I. Effect of nitroglycerin on peripheral blood flow distribution and venous return. J. Pharm. Exp. Ther. 207: 372–380, 1978.
 316. Paaske, W., and P. Sejrsen. Transcapillary exchange of 14C‐insulin by free diffusion in channels of fused vesicles. Acta Physiol. Scand. 100: 437–445, 1977.
 317. Pannier, J. L., and I. Leusen. Regional blood flow in response to exercise in conscious dogs. Eur. J. Appl. Physiol. 36: 255–265, 1977.
 318. Petrini, M. F., H. P. McKenna, T. M. Dwyer, and H. T. Robertson. Effect of temperature on solubility of acetylene. Federation Proc. 39: 964, 1980.
 319. Pollack, A. A., and E. H. Wood. Venous pressure in the saphenous vein at the ankle in man during exercise and changes in posture. J. Appl. Physiol. 1: 649–662, 1949.
 320. Powell, J. R., and M. J. Brody. Participation of H1 and H2 histamine receptors in physiological vasodilator responses. Am. J. Physiol. 231: 1002–1009, 1976.
 321. Proppe, D. W. α‐Adrenergic control of intestinal circulation in heat‐stressed baboons. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 48: 759–764, 1980.
 322. Proppe, D. W. Influence of skin temperature on central thermoregulatory control of leg blood flow. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 50: 974–978, 1981.
 323. Proppe, D. W., G. L. Brengelmann, and L. B. Rowell. Control of baboon limb blood flow and heart rate—role of skin vs. core temperature. Am. J. Physiol. 231: 1457–1465. 1976.
 324. Radigan, L. R., and S. Robinson. Effects of environmental heat stress and exercise on renal blood flow and filtration rate. J. Appl. Physiol. 2: 185–191, 1949.
 325. Redisch, W., L. Wertheimer, C. Delisle, and J. M. Steele. Comparison of various vascular beds in man. Their responses to a simple vasodilator stimulus. Circulation 9: 63–67, 1954.
 326. Riedel, W., C. Hübner, and E. Simon. Two fibre types in the sympathetic vasomotor outflow involved in functional differentiation: their linkage with the respiratory cycle. In: Central Interaction Between Respiratory and Cardiovascular Systems, edited by S. M. Hilton, H. P. Koepchen, and A. Trzebski. New York: Springer‐Verlag, 1980, p. 144–151.
 327. Riedel, W., and M. Iriki. Autonomic nervous control of temperature homeostasis. In: Integrative Functions of the Autonomic Nervous System, edited by C. McC. Brooks, K. Koizumi, and A. Sato. Tokyo: Univ. of Tokyo, 1979, chapt. 30, p. 399–414.
 328. Riedel, W., M. Iriki, and E. Simon. Regional differentiation of sympathetic activity during peripheral heating and cooling in anesthetized rabbits. Pfluegers Arch. 332: 239–247, 1972.
 329. Roberts, M. F., and C. B. Wenger. Control of skin blood flow during exercise: thermal and nonthermal factors. J. Appl. Physiol: Respirat. Environ. Exercise Physiol. 46: 780–786, 1979.
 330. Roberts, M. F., and C. B. Wenger. Control of skin blood flow during exercise by thermal reflexes and baroreflexes. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 48: 717–723, 1980.
 331. Roberts, M. F., C. B. Wenger, J. A. J. Stolwijk, and E. R. Nadel. Skin blood flow and sweating changes following exercise training and heat acclimation. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 43: 133–137, 1977.
 332. Robinson, B. F., S. E. Epstein, G. D. Beiser, and E. Braunwald. Control of heart rate by the autonomic baroreceptor mechanisms and exercise. Circ. Res. 19: 400–411, 1966.
 333. Röcker, L., K. Kirsch, J. Wicke, and H. Stoboy. Role of proteins in the regulation of plasma volume during heat stress and exercise. Isr. J. Med. Sci. 12: 840–843, 1976.
 334. Roddie, I. C., and J. T. Shepherd. The blood flow through the hand during local heating, release of sympathetic vasomotor tone by indirect heating, and a combination of both. J. Physiol. London 131: 657–664, 1956.
 335. Roddie, I. C., and J. T. Shepherd. The effects of carotid artery compression in man with special reference to changes in vascular resistance in the limbs. J. Physiol. London 139: 377–384, 1957.
 336. Roddie, I. C., J. T. Shepherd, and R. F. Whelan. Evidence from venous oxygen saturation measurements that the increase in forearm blood flow during body heating is confined to the skin. J. Physiol. London 134: 444–450, 1956.
 337. Roddie, I. C., J. T. Shepherd, and R. F. Whelan. The contribution of constrictor and dilator nerves to the skin vasodilatation during body heating. J. Physiol. London 136: 489–497, 1957.
 338. Roddie, I. C., J. T. Shepherd, and R. F. Whelan. Reflex changes in human skeletal muscle blood flow associated with intrathoracic pressure changes. Circ. Res. 6: 232–238, 1958.
 339. Rothe, C. F., B. L. Johns, and T. D. Bennett. Vascular capacitance of dog intestine using mean transit time of indicator. Am. J. Physiol. 234 (Heart Circ. Physiol. 3): H7–H13, 1978.
 340. Rowell, L. B. The liver as an energy source in man during exercise. In: Advances in Experimental Medicine and Biology. Muscle Metabolism During Exercise, edited by B. Pernow and B. Saltin. New York: Plenum, 1971, vol. 11, p. 127–141.
 341. Rowell, L. B. Human cardiovascular adjustments to exercise and thermal stress. Physiol. Rev. 54: 75–159, 1974.
 342. Rowell, L. B. Measurement of hepatic‐splanchnic blood flow in man by dye techniques. In: Dye Curves: The Theory and Practice of Indicator Dilution, edited by D. A. Bloomfield. Baltimore, MD: University Park, 1974, chapt. 12, p. 209–229.
 343. Rowell, L. B. The cutaneous circulation. In: Physiology and Biophysics. II. Circulation, Respiration and Fluid Balance, edited by T. C. Ruch and H. D. Patton. Philadelphia, PA: Saunders, 1974, chapt. 12, p. 185–199.
 344. Rowell, L. B. Circulation of skeletal muscle. In: Physiology and Biophysics. II. Circulation, Respiration, and Fluid Balance, edited by T. C. Ruch and H. D. Patton. Philadelphia, PA: Saunders, 1974, chapt. 13, p. 200–214.
 345. Rowell, L. B. The splanchnic circulation. In: Physiology and Biophysics. II. Circulation, Respiration and Fluid Balance, edited by T. C. Ruch and H. D. Patton. Philadelphia, PA: Saunders, 1974, chapt. 14, p. 215–233.
 346. Rowell, L. B. The splanchnic circulation. In: The Peripheral Circulations, edited by R. Zelis. New York: Grune & Stratton, 1975, chapt. 8, p. 163–192.
 347. Rowell, L. B. Competition between skin and muscle for blood flow during exercise. In: Problems with Temperature Regulation During Exercise, edited by E. R. Nadel. New York: Academic, 1977, p. 49–76.
 348. Rowell, L. B. Reflex control of the cutaneous vasculature. J. Invest. Dermatol. 69: 154–166, 1977.
 349. Rowell, L. B. What signals govern the cardiovascular responses to exercise? Med. Sci. Sports 12: 307–315, 1980.
 350. Rowell, L. B. Active neurogenic vasodilatation in man. In: Vasodilatation, edited by P. M. Vanhoutte and I. Leusen. New York: Raven, 1981.
 351. Rowell, L. B., J. R. Blackmon, and R. A. Bruce. Indocyanine green clearance and estimated hepatic blood flow during mild to maximal exercise in upright man. J. Clin. Invest. 43: 1677–1690, 1964.
 352. Rowell, L. B., J. R. Blackmon, R. H. Martin, J. A. Mazzarella, and R. A. Bruce. Hepatic clearance of indocyanine green in man under thermal and exercise stresses. J. Appl. Physiol. 20: 384–394, 1965.
 353. Rowell, L. B., G. L. Brengelmann, J. R. Blackmon, and J. A. Murray. Redistribution of blood flow during sustained high skin temperature in resting man. J. Appl. Physiol. 28: 415–420, 1970.
 354. Rowell, L. B., G. L. Brengelmann, J. R. Blackmon, R. D. Twiss, and F. Kusumi. Splanchnic blood flow and metabolism in heat stressed man. J. Appl. Physiol. 24: 475–484, 1968.
 355. Rowell, L. B., G. L. Brengelmann, J.‐M. R. Detry, and C. Wyss. Venomotor responses to rapid changes in skin temperature in exercising man. J. Appl. Physiol. 30: 64–71, 1971.
 356. Rowell, L. B., G. L. Brengelmann, J.‐M. R. Detry, and C. Wyss. Venomotor responses to local and remote thermal stimuli to skin in exercising man. J. Appl. Physiol. 30: 72–77, 1971.
 357. Rowell, L. B., G. L. Brengelmann, and J. A. Murray. Cardiovascular responses to sustained high skin temperature in resting man. J. Appl. Physiol. 27: 673–680, 1969.
 358. Rowell, L. B., J.‐M. R. Detry, J. R. Blackmon, and C. Wyss. Importance of the splanchnic vascular bed in human blood pressure regulation. J. Appl. Physiol. 32: 213–220, 1972.
 359. Rowell, L. B., J.‐M. R. Detry, G. R. Profant, and C. Wyss. Splanchnic vasoconstriction in hyperthermic man—role of falling blood pressure. J. Appl. Physiol. 31: 864–869, 1971.
 360. Rowell, L. B., P. R. Freund, and S. F. Hobbs. Cardiovascular responses to muscle ischemia in man. Circ. Res. 40, Suppl. 1: 137–147, 1981.
 361. Rowell, L. B., L. Hermansen, and J. R. Blackmon. Human cardiovascular and respiratory responses to graded muscle ischemia. J. Appl. Physiol. 41: 693–701, 1976.
 362. Rowell, L. B., K. K. Kraning Jr., T. O. Evans, J. W. Kennedy, J. R. Blackmon, and F. Kusumi. Splanchnic removal of lactate and pyruvate during prolonged exercise in man. J. Appl. Physiol. 21: 1773–1783, 1966.
 363. Rowell, L. B., K. K. Kraning II, J. W. Kennedy, and T. O. Evans. Central circulatory responses to work in dry heat before and after acclimatization. J. Appl. Physiol. 22: 509–518, 1967.
 364. Rowell, L. B., H. J. Marx, R. A. Bruce, R. D. Conn, and F. Kusumi. Reductions in cardiac output, central blood volume, and stroke volume with thermal stress in normal men during exercise. J. Clin. Invest. 45: 1801–1816, 1966.
 365. Rowell, L. B., J. A. Murray, G. L. Brengelmann, and K. K. Kraning II. Human cardiovascular adjustments to rapid changes in skin temperature in exercising man. Circ. Res. 24: 711–724, 1969.
 366. Rowell, L. B., C. R. Wyss, and G. L. Brengelmann. Sustained human skin and muscle vasoconstriction with reduced baroreceptor activity. J. Appl. Physiol. 34: 639–643, 1973.
 367. Saltin, B. Aerobic work capacity and circulation at exercise in man. Acta Physiol. Scand. 62, Suppl. 230: 1–52, 1964.
 368. Saltin, B., G. Blomqvist, J. H. Mitchell, R. L. Johnson, Jr., K. Wildenthal, and C. B. Chapman. Response to exercise after bed rest and after training. A longitudinal study of adaptive changes in oxygen transport and body composition. Circulation 38, Suppl. 7, 1–78, 1968.
 369. Saltin, B., A. P. Gagge, and J. A. J. Stolwijk. Muscle temperature during submaximal exercise in man. J. Appl. Physiol. 25: 679–688, 1968.
 370. Saltin, B., and L. Hermansen. Esophageal, rectal, and muscle temperature during exercise. J. Appl. Physiol. 21: 1757–1762, 1966.
 371. Saltin, B., and L. B. Rowell. Functional adaptations to physical activity and inactivity. Federation Proc. 39: 1506–1513, 1980.
 372. Saltin, B., and J. Stenberg. Circulatory response to prolonged severe exercise. J. Appl. Physiol. 19: 833–838, 1964.
 373. Schachter, M. Kallikreins and kinins. Physiol. Rev. 49: 509–547, 1969.
 374. Schlant, R. C., P. Novack, W. L. Kraus, C. B. Moore, F. W. Haynes, and L. Dexter. Determination of central blood volume. Comparison of Stewart‐Hamilton method with direct measurements in dogs. Am. J. Physiol. 196: 499–501, 1959.
 375. Schönung, W., C. Jessen, H. Wagner, and E. Simon. Regional blood flow antagonism induced by central thermal stimulation in the conscious dog. Experientia 27: 1291–1292, 1971.
 376. Schönung, W., H. Wagner, C. Jessen, and E. Simon. Differentiation of cutaneous and intestinal blood flow during hypothalamic heating and cooling in anesthetized dogs. Pfluegers Arch. 328: 145–154, 1971.
 377. Schönung, W., H. Wagner, and E. Simon. Neurogenic vasodilatory component in the thermoregulatory skin blood flow response of the dog. Naunyn‐Schmiedebergs Arch. Exp. Pathol. Pharmakol. 273: 230–241, 1972.
 378. Sciaraffa, D., S. C. Fox, R. Stockmann, and J. E. Greenleaf. Human acclimation and acclimatization to heat: a compendium of research—1968‐1978. NASA Tech. Memo. 81181: 1980, p. 1–89.
 379. Scott, J. C., H. C. Bazett, and G. C. Mackie. Climatic effects on cardiac output and the circulation in man. Am. J. Physiol. 129: 102–122, 1940.
 380. Segar, W. E., and W. W. Moore. The regulation of antidiuretic hormone release in man. I. Effects of change in position and ambient temperature on blood ADH levels. J. Clin. Invest. 47: 2143–2151, 1968.
 381. Sejrsen, P. Measurement of cutaneous blood flow by freely diffusible radioactive isotopes: methodological studies on the washout of krypton‐85 and xenon‐133 from the cutaneous tissue in man. Dan. Med. Bull. Suppl. 18: 1–38, 1971.
 382. Sejrsen, P. Capillary permeability measured by bolus injection residue and venous detection. Acta Physiol. Scand. 105: 73–92, 1979.
 383. Selkurt, E. E. Comparison of renal clearances with direct renal blood flow under control conditions and following renal ischemia. Am. J. Physiol. 145: 376–386, 1946.
 384. Selkurt, E. E. Renal blood flow and renal clearance during hemorrhagic shock. Am. J. Physiol. 145: 699–709, 1946.
 385. Selkurt, E. E. Comparison of the bromsulphalein method with simultaneous direct hepatic blood flow. Circ. Res. 2: 155–159, 1954.
 386. Selkurt, E. E. Current status of renal circulation and related nephron function in hemorrhage and experimental shock. I. Vascular mechanisms. Circ. Shock 1: 3–15, 1974.
 387. Selkurt, E. E., and M. J. Elpers. Influence of hemorrhagic shock on renal hemodynamics and osmolar clearance in the dog. Am. J. Physiol. 205: 147–152, 1963.
 388. Senay, L. C., Jr. Movement of water, protein, and crystalloids between vascular and extravascular compartments in heat‐exposed men during dehydration and following limited relief of dehydration. J. Physiol. London 210: 617–635, 1970.
 389. Senay, L. C., Jr. Changes in plasma volume and protein content during exposures of working men to various temperatures before and after acclimatization to heat: separation of the roles of cutaneous and skeletal muscle circulation. J. Physiol. London 224: 61–81, 1972.
 390. Senay, L. C., Jr. Body fluids and temperature responses of heat‐exposed women before and after ovulation with and without rehydration. J. Physiol. London 232: 209–219, 1973.
 391. Senay, L. C., Jr. Plasma volumes and constituents of heat‐exposed men before and after acclimatization. J. Appl. Physiol. 38: 570–575, 1975.
 392. Senay, L. C., Jr. Early response of plasma contents on exposure of working men to heat. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 44: 166–170, 1978.
 393. Senay, L. C., Jr., and S. Fortney. Untrained females: effects of submaximal exercise and heat on body fluids. J. Appl. Physiol. 39: 643–647, 1975.
 394. Senay, L. C., Jr., and R. Kok. Effects of training and heat acclimatization on blood plasma contents of exercising men. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 43: 591–599, 1977.
 395. Senay, L. C., Jr., D. Mitchell, and C. H. Wyndham. Acclimatization in a hot, humid environment: body fluid adjustments. J. Appl. Physiol. 40: 786–796, 1976.
 396. Senay, L. C., Jr., L. D. Prokop, L. Cronau, and A. B. Hertzman. Relation of local skin temperature and local sweating to cutaneous blood flow. J. Appl. Physiol. 18: 781–785, 1963.
 397. Shepherd, J. T. Physiology of the Circulation in Human Limbs in Health and Disease. Philadelphia, PA: Saunders, 1963.
 398. Shepherd, J. T., and P. Vanhoutte. Veins and Their Control. Philadelphia, PA: Saunders, 1975.
 399. Shepherd, J. T., and P. M. Vanhoutte. Role of the venous system in circulatory control. Mayo Clin. Proc. 53: 247–255, 1978.
 400. Shibolet, S., M. C. Landcaster, and Y. Danon. Heat stroke: a review. Aviat. Space Environ. Med. 47: 280–301, 1976.
 401. Shoukas, A. A., and M. C. Brunner. Epinephrine and the carotid sinus baroreceptor reflex. Influence on capacitive and resistive properties of the total systemic vascular bed of the dog. Circ. Res. 47: 249–257, 1980.
 402. Shuster, S. Systemic effects of skin disease. Lancet 29: 907–912, 1967.
 403. Silverberg, A. B., S. D. Shah, M. W. Haymond, and P. E. Cryer. Norepinephrine: hormone and neurotransmitter in man. Am. J. Physiol. 234 (Endocrinol. Metab. Gastrointest. Physiol. 3): E252–E256, 1978.
 404. Simon, E., and W. Riedel. Diversity of regional sympathetic outflow in integrative cardiovascular control: patterns and mechanisms. Brain Res. 87: 323–333, 1975.
 405. Sjöstrand, T. The regulation of the blood distribution in man. Acta Physiol. Scand. 26: 312–327, 1952.
 406. Smith, J. H., S. Robinson, and M. Pearcy. Renal responses to exercise, heat and dehydration. J. Appl. Physiol. 4: 659–665, 1952.
 407. Snellen, J. W. Mean body temperature and the control of thermal sweating. Acta Physiol. Pharmacol. Neerl. 14: 99–174, 1966.
 408. Sparks, H. V. Skin and muscle. In: Peripheral Circulation, edited by P. C. Johnson. New York: Wiley, 1978, chapt. 7, p. 193–230.
 409. Spurr, G. B., and N. J. Dwyer. Hepatic blood flow and indocyanine green disappearance in hyperthermia and endogenous fever. J. Appl. Physiol. 32: 362–368, 1972.
 410. Stegall, H. F. Muscle pumping in the dependent leg. Circ. Res. 19: 180–190, 1966.
 411. Stenson, R., L. Crouse, and D. C. Harrison. Computer measurement of cardiac output by dye dilution: comparison of computer, Fick, and Dow techniques. Cardiovasc. Res. 6: 449–456, 1972.
 412. Stolwijk, J. A. J., M. F. Roberts, C. B. Wenger, and E. R. Nadel. Changes in thermoregulatory and cardiovascular function with heat acclimation. In: Problems with Temperature Regulation During Exercise, edited by E. R. Nadel. New York: Academic, 1977, p. 77–90.
 413. Strandell, T., and J. T. Shepherd. The effect in humans of increased sympathetic activity on the blood flow to active muscles. Acta Med. Scand. Suppl. 472: 146–167, 1967.
 414. Sundlöf, G., and B. G. Wallin. Effect of lower body negative pressure on human muscle nerve sympathetic activity. J. Physiol. London 278: 525–532, 1978.
 415. Sutterer, W. F., and D. A. Bloomfield. Dye densitometers. In: Dye Curves: The Theory and Practice of Indicator Dilution, edited by D. A. Bloomfield. Baltimore, MD: University Park, 1974, p. 393–418.
 416. Taylor, H. L., A. F. Henschel, and A. Keys. Cardiovascular adjustments of man in rest and work during exposure to dry heat. Am. J. Physiol. 139: 583–591, 1943.
 417. Teichmann, J., F. Adaro, A. Veiesteinas, P. Cerretelli, and J. Piiper. Determination of pulmonary blood flow by rebreathing of soluble inert gases. Respiration 31: 296–309, 1974.
 418. Thauer, R. The circulation in hypothermia of nonhibernating animals and men. In: Handbook of Physiology. Circulation, edited by W. F. Hamilton and P. Dow. Washington, DC: Am. Physiol. Soc., 1965, sect. 2, vol. III, chapt. 54, p. 1899–1920.
 419. Thauer, R. Circulatory adjustments to climatic requirements. In: Handbook of Physiology. Circulation, edited by W. F. Hamilton and P. Dow. Washington, DC: Am. Physiol. Soc., 1965, sect. 2, vol. III, chapt. 55, p. 1921–1966.
 420. Thomson, E. M., and K. Pleschka. Vasodilatory mechanisms in the tongue and nose of the dog under heat load. Pfluegers Arch. 387: 161–166, 1980.
 421. Totel, G. L. Physiological responses to heat of resting man with impaired sweating capacity. J. Appl. Physiol. 37: 346–352, 1974.
 422. Traks, E., and S. M. Sancetta. The effects of “dry” heat on the circulation of man. II. Splanchnic hemodynamics. Am. Heart J. 57: 438–448, 1959.
 423. Traks, E., and S. M. Sancetta. The effects of “dry” heat on the circulation of man. Renal hemodynamics. Am. Heart J. 64: 235–242, 1962.
 424. Triebwasser, J. H., R. L. Johnson, Jr., R. P. Burpo, J. C. Campbell, W. C. Reardon, and C. G. Blomqvist. Noninvasive determination of cardiac output by a modified acetylene rebreathing procedure utilizing mass spectrometer measurements. Aviat. Space Environ. Med. 48: 203–209, 1977.
 425. Tyden, G. Aspects of cardiovascular reflex control in man. Acta Physiol. Scand. Suppl. 448: 5–62, 1977.
 426. Upshaw, B. Y., and H. Montgomery. Hereditary anhidrotic ectodermal dysplasia. Arch. Dermatol. Syphilol. 60: 1170–1183, 1949.
 427. Vallbo, Å. B., K.‐E. Hagbarth, H. E. Torebjörk, and B. G. Wallin. Somatosensory, proprioceptive, and sympathetic activity in human peripheral nerves. Physiol. Rev. 59: 919–957, 1979.
 428. Vanhoutte, P. M. Physical factors of regulation. In: Handbook of Physiology. The Cardiovascular System. Vascular Smooth Muscle, edited by D. F. Bohr, A. P. Somlyo, and H. V. Sparks, Jr. Bethesda, MD: Am. Physiol. Soc., 1980, sect. 2, vol. II, chapt. 16, p. 443–474.
 429. Vanhoutte, P. M., and W. J. Janssens. Local control of venous function. Microvasc. Res. 16: 196–214, 1978.
 430. Vatner, S. F. Effects of exercise on distribution of regional blood flows and resistances. In: The Peripheral Circulations, edited by R. Zelis. New York: Grune & Stratton, 1975, chapt. 10, p. 211–233.
 431. Vendsalu, A. Studies on adrenaline and noradrenaline in human plasma. Acta Physiol. Scand. 49, Suppl. 173: 57–69, 1960.
 432. Verpillat, J. M., A. Ghaem, B. Levy, and J. P. Martineaud. La réaction des vaisseaux résistifs et capacitifs de la main au début de l'exercice musculaire. J. Physiol. Paris 68: 51–64, 1974.
 433. Wade, O. L., and J. M. Bishop. Cardiac Output and Regional Blood Flow. Oxford, UK: Blackwell, 1962.
 434. Wade, O. L., B. Combes, A. W. Childs, H. O. Wheeler, A. Cournand, and S. E. Bradley. The effect of exercise on the splanchnic blood flow and splanchnic blood volume in normal man. Clin. Sci. 15: 457–463, 1956.
 435. Wahren, J., G. Ahlborg, P. Felig, and L. Jorfeldt. Glucose metabolism during exercise in man. In: Muscle Metabolism During Exercise. II. Advances in Experimental Medicine and Biology, edited by B. Pernow and B. Saltin. New York: Plenum, 1971, p. 189–203.
 436. Wallin, B. G., W. Delius, and K.‐E. Hagbarth. Comparison of sympathetic nerve activity in normotensive and hypertensive subjects. Circ. Res. 33: 9–21, 1973.
 437. Wallin, B. G., G. Sundlöf, and W. Delius. The effect of carotid sinus nerve stimulation on muscle and skin nerve sympathetic activity in man. Pfluegers Arch 358: 101–110, 1975.
 438. Wallis, W., R. Brenman, and C. R. Honig. A veni‐venomotor response to local congestion. J. Appl. Physiol. 18: 593–596, 1963.
 439. Walther, O.‐E., M. Iriki, and E. Simon. Antagonistic changes of blood flow and sympathetic activity in different vascular beds following central thermal stimulation. II. Cutaneous and visceral sympathetic activity during spinal cord heating and cooling in anesthetized rabbits and cats. Pfluegers Arch. 319: 162–184, 1970.
 440. Wang, Y., R. J. Marshall, and J. T. Shepherd. The effect of changes in posture and of graded exercise on stroke volume in man. J. Clin. Invest. 39: 1051–1061, 1960.
 441. Warren, J. V., C. W. Walter, J. Romano, and E. A. Stead, Jr. Blood flow in hand and forearm after paravertebral block of the sympathetic ganglia. J. Clin. Invest. 21: 665–673, 1942.
 442. Webb‐Peploe, M. M. Effect of changes in central body temperature on capacity elements of limb and spleen. Am. J. Physiol. 216: 643–646, 1969.
 443. Webb‐Peploe, M. M., D. Brender, and J. T. Shepherd. Vascular responses to stimulation of receptors in muscle by capsaicin. Am. J. Physiol. 222: 189–195, 1972.
 444. Webb‐Peploe, M. M., and J. T. Shepherd. Responses of the superficial limb veins of the dog to changes in temperature. Circ. Res. 22: 737–746, 1968.
 445. Webb‐Peploe, M. M., and J. T. Shepherd. Responses of dog's cutaneous veins to local and central temperature changes. Circ. Res. 23: 693–699, 1968.
 446. Webb‐Peploe, M. M., and J. T. Shepherd. Peripheral mechanism involved in response of dogs' cutaneous veins to local temperature change. Circ. Res. 23: 701–708, 1968.
 447. Webb‐Peploe, M. M., and J. T. Shepherd. Response of large hindlimb veins of the dog to sympathetic nerve stimulation. Am. J. Physiol. 215: 299–307, 1968.
 448. Wells, C. L., and S. M. Horvath. Heat stress responses related to the menstrual cycle. J. Appl. Physiol. 35: 1–5, 1973.
 449. Wenger, C. B., and M. F. Roberts. Control of forearm venous volume during exercise and body heating. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 48: 114–119, 1980.
 450. Wenger, C. B., M. F. Roberts, J. A. J. Stolwijk, and E. R. Nadel. Forearm blood flow during body temperature transients produced by leg exercise. J. Appl. Physiol. 38: 58–63, 1975.
 451. Wenger, C. B., M. F. Roberts, J. A. J. Stolwijk, and E. R. Nadel. Nocturnal lowering of thresholds for sweating and vasodilation. J. Appl. Physiol. 41: 15–19, 1976.
 452. Wennergren, G. Aspects of central integrative and efferent mechanisms in cardiovascular reflex control. Acta Physiol. Scand. Suppl. 428: 5–53, 1975.
 453. Whitney, R. J. The measurement of volume changes in human limbs. J. Physiol. London 121: 1–27, 1953.
 454. Whitney, R. J. Circulatory changes in the forearm and hand of man with repeated exposure to heat. J. Physiol. London 125: 1–24, 1954.
 455. Wiggers, C. J. The circulation and circulation research in perspective. In: Handbook of Physiology. Circulation, edited by W. F. Hamilton and P. Dow. Washington, DC: Am. Physiol. Soc., 1962, sect. 2, vol. I, chapt. 1, p. 1–10.
 456. Wilkins, R. W., and L. W. Eichna. Blood flow to the forearm and calf. I. Vasomotor reactions: role of the sympathetic nervous system. Bull. Johns Hopkins Hosp. 68: 425–521, 1941.
 457. Winkler, K., J. A. Larsen, T. Munkner, and N. Tygstrup. Determination of hepatic blood flow in man by simultaneous use of five test substances measured in two parts of the liver. Scand. J. Clin. Lab. Invest. 17: 423–432, 1965.
 458. Wolthius, R. A., S. A. Bergman, and A. E. Nicogossian. Physiological effects of locally applied reduced pressure in man. Physiol. Rev. 54: 566–595, 1974.
 459. Wood, J. E., and D. E. Bass. Responses of the veins and arterioles of the forearm to walking during acclimatization to heat in man. J. Clin. Invest. 39: 825–833, 1960.
 460. Wood, J. E., and J. W. Eckstein. A tandem forearm plethysmograph for study of acute responses of the peripheral veins of man. The effect of environmental and local temperature change, and the effect of pooling blood in the extremities. J. Clin. Invest. 37: 41–50, 1958.
 461. Wyndham, C. H. Effect of acclimatization on circulatory responses to high environmental temperatures. J. Appl. Physiol. 4: 383–395, 1951.
 462. Wyndham, C. H. The physiology of exercise under heat stress. Annu. Rev. Physiol. 35: 193–220, 1973.
 463. Wyndham, C. H., A. J. A. Benade, C. G. Williams, N. B. Strydom, A. Goldin, and A. J. A. Heyns. Changes in central circulation and body fluid spaces during acclimatization to heat. J. Appl. Physiol. 25: 586–593, 1968.
 464. Wyndham, C. H., G. G. Rogers, L. C. Senay, and D. Mitchell. Acclimatization in a hot, humid environment: cardiovascular adjustments. J. Appl. Physiol. 40: 779–785, 1976.
 465. Wyndham, C. H., N. B. Strydom, A. J. van Rensburg, A. J. S. Benade, and A. J. Heyns. Relation between Vo2 max and body temperature in hot humid air conditions. J. Appl. Physiol. 29: 45–50, 1970.
 466. Wyss, C. R. Systemic Pressure‐Volume Relationships in the Dog: Linearity, Low Frequency Dynamic Behavior Effect of Capillary Filtration, and Effect of Active Changes in Splenic Volume. Seattle: Univ. of Washington, 1977. Dissertation.
 467. Wyss, C. R., G. L. Brengelmann, J. M. Johnson, L. B. Rowell, and M. Niederberger. Control of skin blood flow, sweating and heart rate: role of skin vs. core temperature. J. Appl. Physiol. 36: 726–733, 1974.
 468. Wyss, C. R., G. L. Brengelmann, J. M. Johnson, L. B. Rowell, and D. Silverstein. Altered control of skin blood flow at high skin and core temperatures. J. Appl. Physiol. 38: 839–845, 1975.
 469. Wyss, C. R., and L. B. Rowell. Lack of human‐like active vasodilation in skin of heat‐stressed baboons. J. Appl. Physiol. 41: 528–531, 1976.
 470. Wyss, C. R., L. B. Rowell, A. M. Scher, and A. C. Young. Role of the spleen in systemic pressure‐volume curve shifts induced by carotid artery occlusion and norepinephrine infusion. Federation Proc. 36: 437, 1977.
 471. Yamaguchi, N., J. de Champlain, and R. Nadeau. Correlation between the response of the heart to sympathetic stimulation and the release of endogenous catecholamines into the coronary sinus of the dog. Circ. Res. 36: 662–668, 1975.
 472. Youdin, M., and T. Reich. Mercury‐in‐rubber (Whitney) strain gauge. Temperature compensation and analysis of error caused by temperature drift. Ann. Biomed. Eng. 4: 220–231, 1976.
 473. Zanchetti, A. S. Neural regulation of renin release. Experimental evidence and clinical implications in arterial hypertension. Circulation 56: 691–697, 1977.
 474. Zelis, R., and D. T. Mason. Comparison of the reflex reactivity of skin and muscle veins in the human forearm. J. Clin. Invest. 48: 1870–1877, 1969.
 475. Zelis, R., D. T. Mason, and E. Braunwald. Partition of blood flow to the cutaneous and muscular beds of the forearm at rest and during leg exercise in normal subjects and in patients with heart failure. Circ. Res. 24: 799–806, 1969.
 476. Zimmerman, B. G. Comparison of sympathetic vasodilator innervation of hindlimb of the dog and cat. Am. J. Physiol. 214: 62–66, 1968.
 477. Zitnik, R. S., E. Ambrosioni, and J. T. Shepherd. Effect of temperature on cutaneous venomotor reflexes in man. J. Appl. Physiol. 31: 507–512, 1971.
 478. Zoller, R. P., A. L. Mark, F. M. Abboud, P. G. Schmid, and D. D. Heistad. The role of low pressure baroreceptors in reflex vasoconstrictor responses in man. J. Clin. Invest. 51: 2967–2972, 1972.
 479. Zuntz, N., and J. Geppert. Ueber die Natur der normalen Atemreize und den Ort ihren Wirkung. Pfluegers Arch. Gesamte Physiol. Menschen Tiere 38: 337–338, 1886.

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Article Title: Cardiovascular Adjustments to Thermal Stress
 

How to Cite

Loring B. Rowell. Cardiovascular Adjustments to Thermal Stress. Compr Physiol 2011, Supplement 8: Handbook of Physiology, The Cardiovascular System, Peripheral Circulation and Organ Blood Flow: 967-1023. First published in print 1983. doi: 10.1002/cphy.cp020327