Malgoyre Alexandra, Prola Alexandre, Meunier Adelie, Chapot Rachel, Serrurier Bernard, Koulmann Nathalie, Bigard Xavier, Sanchez Hervé
Département des Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France.
Laboratoire de Biologie de l'Exercice pour la Performance et la Santé, Université Evry, Université Paris Saclay, Evry, France.
Front Sports Act Living. 2021 May 28;3:663857. doi: 10.3389/fspor.2021.663857. eCollection 2021.
Altitude camps are used during the preparation of endurance athletes to improve performance based on the stimulation of erythropoiesis by living at high altitude. In addition to such whole-body adaptations, studies have suggested that high-altitude training increases mitochondrial mass, but this has been challenged by later studies. Here, we hypothesized that living and training at high altitude (LHTH) improves mitochondrial efficiency and/or substrate utilization. Female rats were exposed and trained in hypoxia (simulated 3,200 m) for 5 weeks (LHTH) and compared to sedentary rats living in hypoxia (LH) or normoxia (LL) or those that trained in normoxia (LLTL). Maximal aerobic velocity (MAV) improved with training, independently of hypoxia, whereas the time to exhaustion, performed at 65% of MAV, increased both with training ( = 0.009) and hypoxia ( = 0.015), with an additive effect of the two conditions. The distance run was 7.98 ± 0.57 km in LHTH vs. 6.94 ± 0.51 in LLTL (+15%, ns). The hematocrit increased >20% with hypoxia ( < 0.001). The increases in mitochondrial mass and maximal oxidative capacity with endurance training were blunted by combination with hypoxia (-30% for citrate synthase, < 0.01, and -23% for Vmax , < 0.001 between LHTH and LLTL). A similar reduction between the LHTH and LLTL groups was found for maximal respiration with pyruvate (-29%, < 0.001), for acceptor-control ratio (-36%, hypoxia effect, < 0.001), and for creatine kinase efficiency (-48%, < 0.01). 3-hydroxyl acyl coenzyme A dehydrogenase was not altered by hypoxia, whereas maximal respiration with Palmitoyl-CoA specifically decreased. Overall, our results show that mitochondrial adaptations are not involved in the improvement of submaximal aerobic performance after LHTH, suggesting that the benefits of altitude camps in females relies essentially on other factors, such as the transitory elevation of hematocrit, and should be planned a few weeks before competition and not several months.
高原训练营在耐力运动员的训练准备过程中被采用，目的是通过让运动员在高海拔地区生活来刺激红细胞生成，从而提高运动表现。除了这种全身适应性变化外，有研究表明高原训练会增加线粒体质量，但后来的研究对此提出了质疑。在此，我们假设在高海拔地区生活和训练（LHTH）可提高线粒体效率和/或底物利用率。将雌性大鼠暴露于低氧环境（模拟海拔3200米）并训练5周（LHTH），并与生活在低氧环境（LH）或常氧环境（LL）中的久坐大鼠，或在常氧环境中训练的大鼠（LLTL）进行比较。最大有氧速度（MAV）随训练而提高，与低氧无关，而在以MAV的65%强度进行的力竭时间测试中，训练（P = 0.009）和低氧（P = 0.015）均使其增加，且二者具有叠加效应。LHTH组的跑步距离为7.98±0.57千米，而LLTL组为6.94±0.51千米（增加15%，无显著性差异）。低氧状态下血细胞比容增加超过20%（P < 0.001）。耐力训练引起的线粒体质量和最大氧化能力的增加，在与低氧联合时受到抑制（LHTH组和LLTL组相比，柠檬酸合酶降低30%，P < 0.01；Vmax降低23%，P < 0.001）。LHTH组和LLTL组在丙酮酸最大呼吸量方面也有类似降低（-29%，P < 0.001），在呼吸控制率方面（-36%，低氧效应，P < 0.001），以及肌酸激酶效率方面（-48%，P < 0.01）。3-羟基酰基辅酶A脱氢酶不受低氧影响，而棕榈酰辅酶A的最大呼吸量则特异性降低。总体而言，我们的数据表明线粒体适应性变化与LHTH后次最大有氧能力的提高无关，这表明高原训练营对女性的益处主要依赖于其他因素，如血细胞比容的短暂升高，且应在比赛前几周而非几个月进行规划。
