Effects of Endurance Exercise Bouts in Hypoxia, Hyperoxia, and Normoxia on mTOR-Related Protein Signaling in Human Skeletal Muscle

• Axel Przyklenk ^[1] ; Thorben Aussieker ^[1] ; Boris Gutmann ^[1] ; Thorsten Schiffer ; Christian Brinkmann ; Heiko K. Strüder ; Wilhelm Bloch ; Andreas Mierau ; Sebastian Gehlert ^[2]
  1. [1] German Sport University Cologne

     German Sport University Cologne

     Kreisfreie Stadt Köln, Alemania

     
  2. [2] University of Hildesheim

     University of Hildesheim

     Distrito de Hildesheim, Alemania

     
• Localización: Journal of strength and conditioning research: the research journal of the NSCA, ISSN 1064-8011, Vol. 34, Nº. 8, 2020, págs. 2276-2284
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • This study investigated the effects of short-term hypoxia (HY), hyperoxia (PER), and normoxia on anabolic signaling proteins in response to an acute bout of moderate endurance exercise (EEX) before and after an endurance exercise training intervention. Eleven healthy male subjects conducted one-legged cycling endurance exercise (3 x 30 min[middle dot]wk-1 for 4 weeks). One leg was trained under hypoxic (12% O2) or hyperoxic conditions (in a randomized cross-over design), and the other leg was trained in normoxia (20.9% O2) at the same relative workload. Musculus vastus lateralis biopsies were taken at baseline (T0) as well as immediately after the first (T1) and last (T2) training session to analyze anabolic signaling proteins and the myofiber cross-sectional area (FCSA). No significant differences were detected for FCSA between T0 and T2 under all oxygen conditions (p > 0.05). No significant differences (p > 0.05) were observed for BNIP3, phosphorylated RSK1, ERK1/2, FoxO3a, mTOR, and S6K1 between all conditions and time points. Phosphorylated Akt/PKB decreased significantly (p < 0.05) at T1 in PER and at T2 in HY and PER. Phosphorylated rpS6 decreased significantly (p < 0.05) at T1 only in PER, whereas nonsignificant increases were shown in HY at T2 (p = 0.10). Despite no significant regulations, considerable reductions in eEF2 phosphorylation were detected in HY at T1 and T2 (p = 0.11 and p = 0.12, respectively). Short-term hypoxia in combination with moderate EEX induces favorable acute anabolic signaling responses in human skeletal muscle.