A study on the effect of acute hyperbaric oxygen intervention on aerobic endurance.

Introduction: This study aimed to explore the effects of a single mild-dose, acute hyperbaric oxygen (HBO) intervention (1.3 ATA, 100% oxygen, 60 min) on aerobic endurance, cardiac function, pulmonary function, and autonomic nervous system balance in healthy young men.

Methods: Using a randomized crossover design, 14 participants received both the HBO intervention and the control condition (seated rest). For each condition, heart rate variability (HRV), cardiac function, and pulmonary function were assessed before and after the intervention, while aerobic endurance indicators-such as peak oxygen uptake (VO₂peak) and time to exhaustion (TTE)-were measured once following each condition.

Results: HBO significantly decreased resting heart rate (from 63.64 ± 7.75 to 58.79 ± 7.29 bpm, Δ = -7.23%, p = 0.009), with a significant main effect of time (F(1,13) = 7.657, p = 0.016, η²ₚ = 0.371) and a significant time × condition interaction effect (F(1,13) = 4.51, p = 0.048, η²ₚ = 0.268). Root mean square of successive differences (RMSSD) increased from 44.50 [24.50, 59.75] to 54.00 [35.50, 67.50] (Z = 2.261, p = 0.024, r = - 0.604), and standard deviation of successive differences (SDSD) increased from 55.50 [31.75, 76.50] to 71.00 [55.75, 87.75] (Z = 2.701, p = 0.007, r = - 0.722). Both parameters also demonstrated significant differences in condition comparisons (RMSSD: Z = - 2.826, p = 0.005, r = - 0.755; SDSD: Z = - 2.796, p = 0.005, r = - 0.747). No significant changes were observed in aerobic endurance, pulmonary function, or other cardiac function parameters.

Conclusion: A single mild-dose, acute HBO intervention can significantly improve resting heart rate and enhance short-term HRV parameters, suggesting a beneficial effect on parasympathetic activity. However, it does not directly enhance aerobic endurance, and long-term interventions or combined training may be needed to realize its potential benefits.