Effect of Hyperbaric Oxygen After Moderate-Intensity Exercise on Fatigue: A Single-blind Crossover Randomized Trial

ObjectivesAlthough insufficient delivery of oxygen might be a factor in physical and perceived fatigue, the relationship between exposure to hyperbaric oxygen (HBO) and recovery from perceived fatigue remains unexplained. The purpose of this study was to investigate the effects of exposure to HBO after long-duration, medium-intensity training on recovery from perceived fatigue in a single-blind study. MethodsFatigue was induced in nine male university students (mean age: 21.3 years) using an ergometer exercise bike at a moderate intensity of 75% of their maximum heart rate for 60 min. Post-workout, subjects randomly received an intervention comprising exposure to HBO or an air placebo in a single-blind experimental trial. Blood tests were conducted, and perceived fatigue was evaluated by using visual analog scales (VAS) at five time points. One week later, a crossover trial was conducted. ResultsFor the HBO group, pre- to post-intervention mean VAS scores for whole-body fatigue significantly improved from 48.4 to 28.7 (p<0.001). However, in the placebo group, the improvement was not statistically significant. Hematological evaluations, including C-reactive protein level, white blood cell count, creatine kinase level, lactic acid level, T-cell count, CD4/CD8 ratio, and natural killer cell count, did not show any significant between-group differences except only BUN and free fatty acids levels 1.5 h after intervention and Mg levels immediately after intervention. There were also no significant differences in the results of other hematological assessments. ConclusionsThe results of this study showed that perceived fatigue evaluated by VAS scores significantly improved in the HBO group in a blinded trial. However, this was not objectively supported by blood test results. HBO may have effects on recovery from perceived fatigue following long-duration, moderate-intensity exercise. However, the results of this study could not determine the efficacy of HBO on exercise-induced fatigue.