Effect of Adaptation to Passive Hyperthermia on Aerobic Performance and Cardio-Respiratory Endurance in Amateur Athletes

We studied the effects of adaptation to passive hyperthermia (PH) on physical performance and cardiorespiratory endurance in amateur athletes during an exercise test of increasing intensity in laboratory conditions. A total of 28 amateur athletes (men, aged 20.2 ± 2.1 years; team sports: football, handball; experience, four to seven years) were randomized into two groups: experimental group (EG, 14 subjects), which subsequently underwent 24 procedures for adaptation to PH, and the control group (CG, 14 subjects), which underwent 24 interval training sessions on an elliptical trainer machine. We found that adaptation to separate PH (without exercising in the heat) leads to a moderate increase in performance and cardiorespiratory endurance in amateur athletes tested in thermoneutral conditions, in contrast to the absence of interval training effects in the CG. A course of PH procedures leads to an increase in aerobic performance, peak oxygen consumption, and oxygen consumption at the level of anaerobic threshold, increased cardiac performance (increase in oxygen pulse values), as well as the efficiency of pulmonary ventilation and bronchial patency.