Effects of body cooling on aerobic exercise capacity under combined heat stress and mental fatigue
Takashi Naito, Tatsuya Saito, Hirotsugu Morinaga, Mariko Nakamura, Yohei Takai, Nobuhiko Akazawa · Journal of Human Sport and Exercise · 2026
This study examined the effects of body cooling on thermoregulatory and perceptual responses during exercise under combined heat stress and mental fatigue. Seven moderately trained males completed three randomized trials: thermoneutral (22°C, CON), hot (35°C, HOT), and hot with cooling (35°C, COOL). Participants performed a cognitive task during 45 min of cycling at 50% maximal oxygen uptake (VO2max), followed by exercise at 75% VO2max until exhaustion. In COOL, participants ingested ice slurry (1.25 g/kg body mass every 5 min for 30 min) and wore an ice vest starting 40 min before exercise. Absolute time to exhaustion was shorter in HOT (441 ± 83 s) than in CON (623 ± 153 s) and COOL (571 ± 198 s), although differences were not statistically significant. Exploratory analysis showed a smaller reduction in time to exhaustion relative to CON in COOL than in HOT (92.7 ± 22.9% vs. 73.9 ± 21.3%). The increase in rectal temperature from baseline to exercise onset was lower in COOL than HOT. Mental fatigue increased following the cognitive task in all trials, with no differences among trials, and
Objective: cognitive performance was unchanged. These
Findings: suggest that cooling reduced thermal strain but did not significantly improve absolute aerobic exercise capacity.