Hyperthermia: effect on exercise prescription.

Ten healthy male university students pedaled a bicycle ergometer (Monark) for three sessions each lasting 30 minutes. Each subject worked at an individually predicted work load corresponding to approximately 40% of maximal aerobic capacity. The same predicted work load was conducted at 24 degrees C, 44 degrees C and 54 degrees C for each subject. For practical purposes, the results reveal approximately a one beat per minute increase in exercise heart rate for each 1 degree C increase in ambient temperature above neutral (24 degrees C). The practice of exercising cardiac patients in hot ambient temperatures which produce potentially hazardous heart rate levels was challenged. Seasonal reevaluation of exercise heart rate prescriptions is of importance. Hopefully, these findings will also be of some importance to various community gymnasiums and to self-motivated joggers.