Abstract

This study examined the possibility of the anaerobic threshold (AT) being decreased during prolonged constant load exercise in hot conditions and the effect of training status on any such observed decrement. Nine trained cyclists of State-level ability and nine active men with no significant cycling experience performed a maximal capacity bicycle ergometer test during which VO2max, aerobic threshold (AerT) and AT were all found to be significantly greater in the trained group. In both a controlled hot (35 Grad C, 45 RH) and cool (21 Grad C, 50 RH) environment, the subjects then performed a constant load bicycle ergometer exercise test for 30 minutes at an intensity set 12,5 below the workload at which they exceeded their AT. Measurements of oxygen uptake placed the intensity of exercise midway between the AerT and AT for each group. There were no significant differences in oxygen uptake between the hot and cool climates in either group. Pre- and post-exercise blood lactate measurements showed significantly greater lactate accumulation in the hotter climate for both groups. However, the trained cyclists were able to complete the exercise with significantly less lactate accumulation than the other men. It was concluded that the AT of all the men was decreased during prolonged exercise in the heat, but that the men trained specifically in the exercise mode were less affected. Verf.-Referat