1.The performance of muscular work in dry heat—up to 122°F.—was studied in 44 normal young men under rigidly controlled environmental, dietary and work conditions. The stay in the heat varied from 3 hours to 4 days.
2.Comparisons were made between performances on a diet restricted in ascorbic acid intake and a diet supplemented by 500 mg. ascorbic acid daily. The dietary differences were maintained for periods of 4 to 7 days.
3.Pulse rates in rest and in work, rectal temperatures, vasomotor stability tests, rates of sweating, general observations and subjective reports all failed to demonstrate any significant advantage for the men receiving supplements of ascorbic acid.
4.Psychomotor tests and strength tests likewise generally failed to show any advantage in the ascorbic acid supplementation. There apparently was a slight gain in flicker fusion frequency related to the extra intake of vitamin C.
5.Daily sweat losses were of the order of 5 to 8 liters but the total loss of vitamin C in the sweat is entirely negligible.
6.Heat exhaustion occurred with equal frequency in the vitamin C restricted and supplemented groups.