CAPACITY OF YOUNG MALES AND FEMALES FOR RUNNING IN DESERT HEAT

  • 1 January 1977
    • journal article
    • research article
    • Vol. 9  (3) , 137-142
Abstract
Tolerance for sustained activity in the desert at about 40.degree. C was assessed on high school students, mostly athletically oriented and scholastically superior. The 14 males compared with the 12 females had an aerobic capacity greater by about one-half and a percentage of body fat smaller by about one-half. Each sex attained about the same percentage of aerobic capacity in their maximal sustained effort. This involved an increase in metabolic rate of 3-5 fold in females and 6-8 fold in males. In maximal sustained effort responses of males and females were alike with respect to rectal and skin temperatures and heart rate. At a rate at which nearly all walked for 1 h, 100 m/min, there were no significant differences in metabolic rate, sweat rate nor in composition of sweat. Running at 120 m/min required maximal effort by most females; their maximal sweat rates ranged from 7.4-14.2 ml/m2.cntdot.min. Most males were able to run at 160 m/min for one-half hour-1 h; their maximal sweat rates ranged from 11.3-14.6 m/m2.cntdot.min. Superior capacity of males over females for sustained exercise in desert heat if related to their higher aerobic capacity and not to a difference in capacity for thermoregulation.