LAUSR

PURPOSE To compare the impact of hot-humid environmental conditions on performance outcomes, thermoregulatory responses, and thermal perception during exercise between elite para- and able-bodied (AB) athletes. METHODS 20 elite para-athletes (para-cycling and wheelchair tennis) and 20 elite AB athletes (road cycling, mountain biking, beach volleyball) performed an incremental exercise test in a temperate environment (mean ± SD: 15.2 ± 1.2 °C, relative humidity 54 ± 7%) and a hot-humid environment (31.9 ± 1.6 °C, 72 ± 5%). Exercise tests started with a 20-min warm-up at 70% of maximal heart rate, after which power output increased by 5% every 3 min until volitional exhaustion. RESULTS Time to exhaustion was shorter in hot-humid versus temperate conditions, with equal performance loss for para- and AB athletes (median [IQR]: 26 [20-31]% vs. 27 [19-32]%; p = 0.80). AB athletes demonstrated larger exercise-induced increases in gastrointestinal temperature (Tgi) in hot-humid versus temperate conditions (2.2 ± 0.7 vs. 1.7 ± 0.5, p < 0.001), whereas Tgi responses in para-athletes were similar between conditions (1.3 ± 0.6 vs. 1.3 ± 0.4, p = 0.74). Para- and AB athletes showed similar elevations in peak skin temperature (p = 0.94), heart rate (p = 0.67), and thermal sensation score (p = 0.64) in hot-humid versus temperate conditions. CONCLUSIONS Elite para-athletes and AB athletes demonstrated similar performance decrements during exercise in hot-humid versus temperate conditions, whilst Tgi elevations were markedly lower in para-athletes. We observed large inter-individual variation within both groups, suggesting that in both para- and AB athletes, personalized heat mitigation plans should be developed based on individual thermal testing.