Spitler D L, Horvath S M, Kobayashi K, Wagner J A
Eur J Appl Physiol Occup Physiol. 1980;43(2):157-66. doi: 10.1007/BF00422446.
Twelve subjects completed a progressive treadmill test to maximal aerobic capacity while breathing air or a 79% helium--21% oxygen gas mixture (HeO2). Metabolic and thermoregulatory responses to work while breathing the two mixtures were compared at rest, 30-40%, 60-70%, and 85-90% of maximal performance, and at maximal effort. Ventilation, ventilatory equivalent, and respiratory rates were increased and oxygen uptakes decreased by breathing HeO2 when the level of work exceeded 85-90% of maximum. Heat loss through the respiratory tract was greater breathing HeO2. The reduction in maximal oxygen uptake is probably due to a reduction in the oxygen cost of breathing a less dense gas. It was not related to a lower body temperature and probably not to O2 transport or circulatory limitation. HeO2 breathing had no effect on maximal mechanical work capacity.
12名受试者在呼吸空气或79%氦气-21%氧气混合气体（HeO2）的情况下，完成了一项递增式跑步机测试，直至达到最大有氧能力。在休息、最大运动能力的30%-40%、60%-70%、85%-90%以及最大努力程度时，比较了呼吸这两种混合气体时的代谢和体温调节反应。当工作强度超过最大强度的85%-90%时，呼吸HeO2会使通气量、通气当量和呼吸频率增加，而摄氧量减少。通过呼吸道的热量散失在呼吸HeO2时更大。最大摄氧量的降低可能是由于呼吸密度较小的气体时呼吸的氧气成本降低。它与较低的体温无关，可能也与氧气运输或循环限制无关。呼吸HeO2对最大机械工作能力没有影响。
