Mild hyperbaric oxygen therapy on subjective sleep quality, aerobic, anaerobic exercise test, brain and muscle tissue oxygenation response in Chinese University male athletes after muscle fatigue

BACKGROUND: This study aimed to investigate the recovery effects and timing sequence of Mild Hyperbaric Oxygen Therapy (MHOT) on physiological responses and exercise capacity following muscle fatigue induced by simulated cycling exercise. METHODS: This study employed a controlled crossover design. Twelve Chinese secondary national-level male athletes participated in two identical trials (CON and MHOT). Each trial consisted of one daily session for six consecutive days. In each session, participants first completed 90 min of cycling exercise to induce fatigue. Afterward, six participants underwent the CON intervention, while the other six received MHOT; the interventions were switched in the alternate trial. Physiological outcomes included the Pittsburgh Sleep Quality Index (PSQI), aerobic exercise exhaustion test (maximal oxygen uptake (V̇O₂max), maximal cycling power, maximal cycling time), Wingate anaerobic test, and brain and muscle tissue oxygenation indices. Measurements were taken at six time points across the study. RESULTS: After six interventions, the MHOT group showed significantly better subjective sleep quality compared with CON (p < 0.05). MHOT also increased muscle and brain oxygenated hemoglobin as well as muscle total hemoglobin (p < 0.05). At 24 h after the sixth intervention, the MHOT group demonstrated higher V̇O₂max, maximal cycling power, and cycling time compared with CON (p < 0.05). However, no significant differences were observed between MHOT and CON in Wingate test indices (p > 0.05). CONCLUSIONS: Repeated MHOT sessions promoted recovery by improving subjective sleep quality, enhancing brain and muscle oxygenation, and augmenting aerobic exercise performance compared with CON. However, MHOT did not significantly influence anaerobic capacity as assessed by the Wingate test.