Comparative efficacy of intermittent hypoxic training modalities on athletes' performance: a systematic review with...

A systematic review and network meta-analysis of 29 randomized controlled trials (603 trained athletes) was conducted. Pairwise and network meta-analyses were performed to compare the effects of three different type of hypoxic training: IHT, RSH, and SIH, against intensity-matched normoxic training on aerobic and anaerobic capacity. Simulated altitude was examined as an exploratory subgroup moderator. Exploratory subgroup analyses indicated that moderate and high simulated altitudes enhanced aerobic capacity, whereas anaerobic improvement occurred only at moderate altitude. Modality-specific analyses revealed a distinct outcome-dependent hierarchy: IHT (pairwise SMD = 0.55; network SMD = 0.53) and RSH (pairwise SMD = 0.43; network SMD = 0.40) significantly improved aerobic capacity, whereas SIH did not. For anaerobic capacity, only RSH showed significant improvement (pairwise SMD = 0.57; network SMD = 0.55). Probability ranking indicated IHT ranked highest for aerobic capacity (SUCRA = 84.2) and RSH for anaerobic outcomes (SUCRA = 95.6). IHT appears most suitable for aerobic development in endurance athletes, while RSH seems to offer the most consistent benefits across both aerobic and anaerobic domains. These findings provide directional guidance for hypoxic training prescription, pending confirmation from adequately powered head-to-head trials with standardized protocols and long-term follow-up.