Non-Thermal Factors are Important in the Control of Skin Blood Flow During Exercise Only Under High Physiological Strain

摘要

Several authors have argued that skin blood flow (SkBF) during exercise is less than during rest at the same levels of body core and whole-body skin temperatures (T sub C and T sub sk). Since such an effect does not prevent SkBF during exercise from rising above pre-exercise levels, it is sometimes called a relative cutaneous vasoconstriction. Such a vasoconstriction is considered to be either part of a thermoregulatory adjustment during exercise (elevated thermoregulatory set-point) or a compensatory response to allow adequate perfusion of exercising muscle. In this paper, some of the pertinent experimental evidence is reviewed, and the following conclusions are reached: a) the evidence does not support a change in thermoregulatory set-point during exercise; b) under conditions of high physiological strain (high T sub sk and intense exercise), there is quite clearly a relative cutaneous vasoconstrictor effect of exercise; c) the evidence does not support such an effect under more moderate conditions; and d) it is likely that, under mild to moderate conditions, other compensatory cardiovascular responses are sufficient to allow adequate perfusion of exercising muscle and are invoked in preference to relative cutaneous vasoconstriction, which has been demonstrated only at higher levels of strain. The thermoregulatory SkBF required during sustained exercise is thus maintained as much as possible.