Puthon Lara, Bouzat Pierre, Robach Paul, Favre-Juvin Anne, Doutreleau Stéphane, Verges Samuel
U1042, INSERM, Building Jean Roget, Faculty of Medicine, F-38042, Grenoble, France.
HP2 Laboratory, Université Grenoble Alpes, Building Jean Roget, Faculty of Medicine, F-38042, Grenoble, France.
Exp Physiol. 2017 Apr 1;102(4):436-447. doi: 10.1113/EP085949. Epub 2017 Feb 28.
What is the central question of this study? This study aimed to determine the effect of ageing on cardiorespiratory and tissue oxygenation responses to hypoxia during maximal incremental exercise. What is the main finding and its importance? Older healthy subjects had preserved hypoxic cardiorespiratory and tissue oxygenation responses at rest and during moderate exercise. At maximal exercise, they had a reduced hypoxic ventilatory response but similar maximal power output reduction compared with young individuals. This study suggests that until moderate exercise, hypoxic responses are preserved until the age of 70 years and therefore that ageing is not a contraindication for high-altitude sojourn. This study assessed the effects of ageing on cardiorespiratory and tissue oxygenation responses to hypoxia both at rest and during incremental maximal exercise. Sixteen young (20-30 years old) and 15 older healthy subjects (60-70 years old) performed two maximal incremental cycling tests in normoxia and hypoxia (inspiratory oxygen fraction 12%). Cardiorespiratory responses, prefrontal cortex and quadriceps tissue oxygenation (near-infrared spectroscopy) were measured during exercise as well as during hypercapnia at rest. The hypoxic ventilatory response was similar in young compared with older individuals at rest and during moderate-intensity exercise (50% maximal power output: young 0.9 ± 0.2 versus older 1.1 ± 0.8 l min % ; P > 0.05) but larger in young subjects during high-intensity exercise (maximal power output: 2.2 ± 0.8 versus 1.8 ± 1.1 l min % ; P < 0.05). The hypoxic cardiac response did not differ between groups both at rest and during exercise. During exercise in hypoxia, young subjects showed greater deoxygenation than older subjects, at both the prefrontal cortex and quadriceps levels. The hypoxia-induced reduction in maximal power output (young -32 ± 5% versus older -30 ± 6%; P > 0.05) and the hypercapnic responses did not differ between groups. Older healthy and active individuals below the age of 70 years have cardiorespiratory and tissue oxygenation responses to hypoxia similar to young individuals both at rest and during moderate-intensity exercise. Despite a lower hypoxic ventilatory response at maximal exercise, older individuals have similar oxygen desaturation and maximal power output reduction compared with young subjects.
本研究的核心问题是什么？本研究旨在确定衰老对最大递增运动期间心肺和组织对低氧的氧合反应的影响。主要发现及其重要性是什么？健康的老年受试者在静息和中度运动时，其低氧心肺和组织氧合反应得以保留。在最大运动时，他们的低氧通气反应降低，但与年轻人相比，最大输出功率降低程度相似。本研究表明，直到中度运动，低氧反应在70岁之前都得以保留，因此衰老并非高海拔停留的禁忌证。本研究评估了衰老对静息和递增最大运动期间心肺和组织对低氧的氧合反应的影响。16名年轻（20 - 30岁）和15名健康老年受试者（60 - 70岁）在常氧和低氧（吸入氧分数12%）状态下进行了两次最大递增自行车测试。在运动期间以及静息时高碳酸血症期间测量了心肺反应、前额叶皮层和股四头肌组织氧合（近红外光谱法）。在静息和中度强度运动（50%最大输出功率：年轻组0.9±0.2对比老年组1.1±0.8升·分钟⁻¹·%⁻¹；P>0.05）时，年轻个体与老年个体的低氧通气反应相似，但在高强度运动时（最大输出功率：年轻组2.2±0.8对比老年组1.8±1.1升·分钟⁻¹·%⁻¹；P<0.05）年轻受试者的低氧通气反应更大。两组在静息和运动时的低氧心脏反应无差异。在低氧运动期间，年轻受试者在前额叶皮层和股四头肌水平的脱氧程度均高于老年受试者。低氧诱导的最大输出功率降低（年轻组-32±5%对比老年组-30±6%；P>0.05）以及高碳酸血症反应在两组间无差异。70岁以下健康且活跃的老年个体在静息和中度强度运动时，其对低氧的心肺和组织氧合反应与年轻个体相似。尽管在最大运动时低氧通气反应较低，但老年个体与年轻受试者相比，有相似的氧饱和度降低和最大输出功率降低。
