Year: 2025
Type: article
Abstract: This study is the first to determine how hypoxia affects human muscle fatigue kinetics and metabolic perturbations during intense dynamic exercise. Using randomized, single-blinded crossover designs, three trials of two-legged knee extensions were performed under hypoxic (HYP, FiO₂ 0.135) and normoxic (NOR) conditions. Trial 1 ( n = 8): quadriceps femoris twitch force (F tw ) was measured before, during, and after 4 min intense exercise followed by exhaustive exercise. Maximal voluntary contraction (MVC) was measured pre- and post-exercise. Trial 2 ( n = 8): muscle lactate and pH were determined before and after 4 min intense exercise. Trial 3 ( n = 6): blood was sampled frequently from the femoral artery and vein during intense exhaustive exercise. Dynamic F tw decreased more ( P < 0.05) in HYP from 60s of exercise and onwards. After 4 min, isometric F tw decreased more ( P < 0.05) in HYP, whereas MVC was similar between conditions. At exhaustion, isometric F tw and MVC were similar between conditions despite HYP exercise time being 55 ± 17% of NOR ( P < 0.01). Muscle lactate and pH in- and decreased more ( P < 0.001), respectively, after 4 min in HYP. Exercise-induced blood metabolites disturbances were largely unaffected by hypoxia. Conclusively, moderate hypoxia accelerated muscular fatigue from 60s and onwards. Hypoxia caused higher muscle but not blood lactate and H + accumulation rates.
Source: Scientific Reports
Authors: Jacob Bejder, Jonathan Graae, Jakob Boye Andersen, Ricardo Augusto Barbieri, Eduardo Zapaterra Campos, Jens Bangsbo, Lars Nybo, Nikolai Baastrup Nordsborg
Language: English
Topic: High Altitude and Hypoxia
Subfield: Genetics
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $2,690
OpenAlex ID: W4409707421