title: Capacity of young males and females for running in desert heat.
abstract: Tolerance for sustained activity in the desert at about 40 degrees 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 to 5 fold in females and 6 to 8 fold in males. In maximal sustained effort responses of males and females were alike in respect to rectal and skin temperatures and heart rate. At a rate at which nearly all walked for one hour, 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 to 14.2 ml/m2.min. Most males were able to run at 160 m/min for one-half hor to one hour; their maximal sweat rates ranged from 11.3 to 14.6 m/m2.min. Superior capacity of males over females for sustained exercise in desert heat is related to their higher aerobic capacity and not to a difference in capacity for thermoregulation.
mesh_terms: D000293:Adolescent; D001794:Blood Pressure; D003889:Desert Climate; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D012119:Respiration; D012420:Running; D012881:Skin Temperature; D013178:Sports Medicine; D013542:Sweat / Q000032:analysis; D013546:Sweating