Effects of Extreme Heat and Cold on Human Skin. II. Surface Temperature, Pain and Heat Conductivity in Experiments With Radiant Heat

Abstract

The surface temp. of human skin, irradiated with strong infrared radiant heat, was observed by means of fine contact thermocouples. The skin reaches its pain point within 2-60 sec., depending on radiation intensity and on initial skin temp. Peripheral blood flow and wetness of the skin do not influence temp. or pre-pain time for higher radiation intensities. The pain threshold temp. and the depth of pain receivers in the skin are 44.8[degree] C and 0.1 mm., respectively. From the data the heat conductivity of the upper skin can be derived; it does not depend on blood flow, except for acral parts, such as finger tips. Additional expts. concern heat burns and effects of extremely cold air on bare skin. Precooling the skin seems to offer an effective protection against overheating.