Monitoring training to assess changes in fitness and fatigue: The effects of training in heat and hypoxia

Abstract

This study examined the association between monitoring tools, training loads, and performance in concurrent heat and hypoxia (H + H) compared with temperate training environments. A randomized parallel matched-group design involved 18 well-trained male cyclists. Participants performed 12 interval sessions (3 weeks) in either H + H (32 ± 1 °C, 50% RH, 16.6% O2 normobaric hypoxia) or control (21 °C, 50% RH, 21% O2 ), followed by a seven-session taper (3 weeks; 21 °C, 50% RH, 21% O2 ), while also maintaining external training (∼ 6-10 h/week). A 20-km time trial (TT) was completed pre- and post-training block (21 °C, 50% RH, 21% O2 ). Before each TT and once weekly, a 4-min cycle warm-up (70% 4-min mean maximum power) was completed. Visual analog scale rating for pain, recovery, and fatigue was recorded before the warm-up, with heart rate (HREx ), heart rate recovery (HRR), and rating of perceived exertion (RPEWU ) recorded following. Training load was quantified using the session rating of perceived exertion (sRPE) method throughout. Overall TT improved 35 ± 47 s with moderate correlations to HRR (r = 0.49) and recovery (r = -0.55). H + H group had a likely greater reduction in HREx [ES = -0.50 (90% CL) (-0.88; 0.12)] throughout and a greater sRPE (ES = 1.20 [0.41; 1.99]), and reduction in HRR [ES = -0.37 (-0.70;-0.04)] through the overload. RPEWU was associated with weekly training load (r = 0.37). These findings suggest that recovery and HRR in a temperate environment may be used as simple measures to identify an athlete's readiness to perform. Alternatively, the relationship of RPEWU and training load suggests that perception of effort following a standardized warm-up may be a valid measure when monitoring an athlete's training response, irrespective of the training environment.