Effect of Cooling Isolated Parts upon the Comfort of Man Resting in Hot Humid Environment ∗

Hill 1 and Kuno and Ikeuchi 2 inhibited sweating in human subjects by cooling isolated portions of the body. They made no attempt to correlate the temperature of the bath cooling the part, the temperature and humidity of the environment, and the size of the area cooled, with the quantity of sweat and the comfort of the subjects. Nor were attempts made to evaluate the efficiency of local cooling on the adaptation of a man to a very uncomfortable, hot, and humid environment. The present studies were undertaken to throw light upon these problems.

Methods and Materials. The studies were conducted in an air-conditioned room with the temperature and relative humidity controlled at 75° ± 1°F and 50% ± 2%, respectively. The temperature and relative humidity of the room could be raised within 15 minutes to the desired levels as indicated below. The room in which the subjects rested contained very little of the recording apparatus in order to reduce the psychic disturbance to a minimum. Twenty-six (25 white and one negro) young adults, trained subjects who had had considerable experience around research laboratories, were used. They varied from 22 to 37 years of age. Three of the subjects were females.

The rate of water loss was measured from the skin of the right index fingertip, right forearm, and midepigastrium by a method described by Neumann, Cohn and Burch, 3 The oral and rectal temperatures were measured and recorded photographically by means of copper-constantan thermocouples. The variations in the volume of pulsations of the right index fingertip and right second toetip were measured by means of a modification of the sensitive pneumoplethysmographic method of Turner. 4