Responses to exercise as related to age and environmental temperature

¹ Department of Anatomy and Physiology, Indiana University, Bloomington, Indiana

The responses of two subjects to exercise were studied after a time lapse of 29 years. Environmental temperatures varied from 0 to 50 C and oxygen consumptions from the resting value to about ten times basal metabolic rate. In DBD, present age 70, the heart rates were about the same in easy and moderate work at temperatures up to 40 C but much higher at 50 C. In FC, present age 50, at all work levels the heart rates were the same up to 20 C, lower at 30 and 40 C, and higher at 50 C. The aerobic capacity of both subjects had declined about one-fourth. Thus the responses to the stress of extreme heat showed little loss, whereas there was considerable loss in the ability to withstand the stress of hard work.