Vascular convection of heat from active muscle to overlying skin

¹ Department of Physiology, St. Louis University School of Medicine, St. Louis, Missouri

Both thermocouple and radiometer measurements revealed marked elevations in temperature of skin immediately over actively working muscles of the forearm and leg. Such localized increases in the surface temperature were confined to skin overlying rhythmically contracting muscle. They were attributed to a direct vertical vascular convection of heat from the muscle to the overlying skin because they were prevented by blocking perfusion or by surgical severance of skin from underlying tissue and because of the character of the temperature gradient in the intervening tissue. The argument for a venous rather than an arterial convection was based on a) the effects of compression of the superficial veins on the temperature changes, b) the absence of effect on the latter by electrophoresis of adrenaline into the skin, which greatly reduced arterial perfusion of the skin, c) the absence of evidence of arterial dilation in the skin and d) the lack of relation of the location of arterial twigs to the topography of the temperature rise.