Hyperbaric oxygen therapy (HBOT) is a treatment that helps heal the body using chambers with high-pressure oxygen. HBOT repairs damaged tissues by increasing oxygen intake and providing 100% pure oxygen. This treatment can boost individual performance levels, but—until now—it hasn’t been put to the test with a placebo-controlled clinical trial. The effects of HBOT on physical performance have yet to be evaluated. Between May 2018 and December 2020, a team of doctors and healthcare specialists researched HBOT and how it affects physical performance using a double-blind controlled study. This study aimed to determine the effects of intermittent hyperbaric oxygen therapy on physical performance and mitochondrial function in 40-to-50-year-old athletes.