Maximal cardiorespiratory responses to one- and two-legged cycling during acute and long-term exposure to 4300 meters altitude.

摘要: During exposure to altitudes greater than about 2200 m, maximal oxygen uptake (\(\dot V_{O_{2max} } \)) is immediately diminished in proportion the reduction partial pressure of inspired air. If lasts longer a couple days, an increase arterial content (CaO2), due hemoconcentration and saturation, occurs. However, there also cardiac output Q_{\max }\)) at altitude which offsets CaO2 and, therefore,\(\dot \) does not improve. The purpose this investigation was study contribution working muscles without potentially confounding problem reduced\(\dot }\). approach used have seven male subjects (aged 17 24 years) perform one- two-legged\(\dot tests on cycle ergometer sea level (SL, PIO2 = 159 Torr), after 1 h 4300 m simulated (SA, 94 Torr) during two weeks residence summit Pikes Peak, CO. (pP, Torr). Cardiac limits performance two-legged cycling but limit one-legged cycling. study, changed from 189±3 (mean ±SE) SL 161±4 ml·L−1 SA (SL vs. SA,p<0.01) 200±6 PP PP,p<0.05; PP,p<0.01). Two-legged\(\dot decreased 3.64±0.26 L·min−1 2.70±0.14 (p<0.01) 2.86±0.16 (p<0.01). One-legged\(\dot 2.95±0.22 2.25±0.17 improved 2.66±0.18 (SA PP,p<0.05). Since only one-legged\(\dot increased as more made available muscles, altitude-induced in\(\dot }\) can be implicated being responsible for