BMC Sports Sci Med Rehabil. 2026 Jul 6. doi: 10.1186/s13102-026-01837-z. Online ahead of print.
ABSTRACT
BACKGROUND: Normobaric hyperoxic recovery has been proposed as a post-exercise strategy to improve subsequent exercise performance, but the overall performance evidence and the consistency of accompanying physiological recovery markers remain unclear. This systematic review and meta-analysis primarily evaluated the effect of normobaric hyperoxic recovery on subsequent performance, with selected physiological outcomes interpreted as secondary and exploratory evidence.
METHODS: We systematically reviewed studies examining normobaric hyperoxic recovery after exercise. Performance was prespecified as the primary outcome. Peripheral oxygen saturation (SpO₂), heart rate (HR), and blood lactate (BLa) were treated as secondary outcomes. After full-text verification, 19 reports were retained, yielding 21 study entries for synthesis. Because many studies used crossover, repeated-measures, or within-subject designs and most did not report sufficient paired-variance information, the main quantitative syntheses used arm-level summary statistics and random-effects models with standardized mean differences (Hedges’ g).
RESULTS: The primary performance analysis included 16 study entries and estimated a small-to-moderate effect in favor of normobaric hyperoxic recovery (SMD = 0.42, 95% CI 0.22 to 0.63; I² = 0%). This estimate was not materially altered in leave-one-out, trim-and-fill, fail-safe N, and prespecified structural sensitivity analyses. For secondary outcomes, 10 study entries contributed to the BLa analysis, which showed no clear pooled effect (SMD = 0.14, 95% CI -0.15 to 0.43; I² = 0%). Although funnel-plot asymmetry was detected for BLa, trim-and-fill did not materially alter the pooled estimate. HR results were based on 2 exploratory study entries and showed no clear pooled effect (SMD = 0.29, 95% CI -0.35 to 0.93; I² = 0%). SpO₂-related outcomes were highly heterogeneous (I² = 90.0%), and this inconsistency persisted after sensitivity analyses, supporting narrative rather than pooled inferential interpretation.
CONCLUSIONS: Normobaric hyperoxic recovery was associated with a modest, directionally consistent effect in favor of subsequent performance. In contrast, the secondary physiological outcomes provided limited and inconsistent evidence. No clear pooled effect was observed for blood lactate, heart-rate findings were exploratory, and SpO₂ outcomes were too heterogeneous to support a stable pooled conclusion. Overall, the findings suggest a possible performance benefit of normobaric hyperoxic recovery, while physiological outcomes should be interpreted as descriptive and hypothesis-generating rather than as evidence of a consistent physiological recovery response.
PMID:42410467 | DOI:10.1186/s13102-026-01837-z
