Inter-individual variability in peripheral oxygen saturation and repeated sprint performance in hypoxia: an observational study of highly-trained subjects

• Published in: Frontiers in sports and active living Vol. 6; p. 1452541
• Main Authors: Takei, Naoya, Muraki, Ryuji, Girard, Olivier, Hatta, Hideo
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 08.08.2024
• Subjects: hypoxic training; individual variation; oxygen saturation; repeated sprint ability; simulated altitude; Sports and Active Living; individual variation; oxygen saturation; repeated sprint ability; simulated altitude; hypoxic training
• ISSN: 2624-9367; 2624-9367
• DOI: 10.3389/fspor.2024.1452541

Individual variations in peripheral oxygen saturation (SpO 2 ) during repeated sprints in hypoxia and their impact on exercise performance remain unclear despite fixed external hypoxic stimuli (inspired oxygen fraction: FiO 2 ). This study examined SpO 2 individual variations during repeated sprints in hypoxia and their impact on exercise performance. Thirteen highly-trained sprint runners performed 10 × 10-s cycle sprints with 30-s passive recoveries in normobaric hypoxia (FiO 2 : 0.150). Mean power output (MPO), post-sprint SpO 2 , and heart rate for each sprint were assessed. Sprint decrement score (S dec ), evaluating fatigue development, was calculated using MPO variables. Participants were categorized into a high saturation group (HiSat, n  = 7) or a low saturation group (LowSat, n  = 6) based on their mean post-sprint SpO 2 (measured 10–15 s after each sprint). Individual mean post-sprint SpO 2 ranged from 91.6% to 82.2%. Mean post-sprint SpO 2 was significantly higher ( P  < 0.001, d  = 1.54) in HiSat (89.1% ± 1.5%) than LowSat (84.7% ± 1.6%). A significantly larger decrease in S dec ( P  = 0.008, d  = 1.68) occurred in LowSat (−22.3% ± 2.3%) compared to HiSat (−17.9% ± 2.5%). MPO ( P  = 0.342 d  = 0.55) and heart rate ( P  = 0.225 d  = 0.67) did not differ between groups. There was a significant correlation ( r  = 0.61; P  = 0.028) between SpO 2 and S dec . In highly-trained sprint runners, individual responses to hypoxia varied widely and significantly affected repeated sprint ability, with greater decreases in SpO 2 associated with larger performance alterations (i.e., larger decrease in S dec ).