Effects of intermittent hypoxia and hypoxia-hyperoxia exposure on recovery from delayed onset muscle soreness in physically active men: protocol for a randomized controlled trial.

Introduction: The objective of this study is to evaluate whether intermittent hypoxia can enhance physical recovery following the induction of delayed onset muscle soreness (DOMS). Methods and analysis: A randomized controlled trial will be conducted with male participants aged 18-35 years who engage in at least two organized training sessions per week. After a DOMS induction protocol targeting the hamstrings, participants will be randomized to receive either intermittent hypoxia, hypoxia-hyperoxia, or placebo for five consecutive days. During this period, several outcome variables will be assessed, including: cognitive function-attention and executive functions (D2 Test and Trail Making Test A and B); stress (DASS-21 questionnaire); physical performance-VO Ethics and disseminations: The study was reviewed and approved by the Medical Ethics Committee of Hospital Clínico San Carlos, Madrid, Spain (internal code 25/446-E) prior to data collection. If effective, intermittent hypoxia and hypoxia-hyperoxia could be implemented as non-pharmacological recovery strategies for athletes and physically active populations, offering a novel alternative to current methods with inconsistent results. The findings may guide future research on hypoxic conditioning, inform clinical practices for rehabilitation and performance recovery, and potentially shape policy regarding safe, evidence-based applications of hypoxia in sports medicine. Clinical Trial Registration: https://www.anzctr.org.au/, registration code ACTRN12625001404415.