Responses of distance runners and sprinters to exercise in a hot environment.
The responses of highly trained distance runners and track sprinters and age-matched untrained men were compared during bicycle ergometry in a 40 degree temperature-controlled environmental chamber. There were no differences among groups in rectal temperature following the 90 min exercise bout. Distance runners had a lower heart rate than either sprinters or untrained subjects. There was no difference in heart rate between sprinters and untrained subjects. Distance runners and sprinters had a much greater sweat rate than untrained subjects and dissipated a greater proportion of their total heat load by evaporation of sweat. Sprinters, however, had a lower sweat rate than distance runners in the hot environment and could only maintain as low a skin temperature as distance runners for 75 min of the 90 min session. Both aerobic training and anaerobic training confer some degree of protection from heat injury during exercise in a hot environment. However, sprinters have a higher heart rate and cannot sustain a low skin temperature as long as distance runners. Sprinters lost their advantage over untrained subjects in skin temperature after 75 min of exercise in a hot environment and did not have a lower heart rate than untrained subjects. Distance runners had a significantly lower heart rate and maintained a lower skin temperature than untrained subjects for the entire 90 min exercise bout.
Irion
G L
GL
Biokinetics Research Laboratory, College of HPERD, Temple University, Philadelphia, Pennsylvania.
D000064:Acclimatization; D000328:Adult; D001833:Body Temperature Regulation; D005080:Exercise Test; D006339:Heart Rate; D006358:Hot Temperature; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D010806:Physical Education and Training; D010807:Physical Endurance; D012420:Running; D013546:Sweating