Ward S A, Whipp B J, Poon C S
Respir Physiol. 1982 Sep;49(3):267-77. doi: 10.1016/0034-5687(82)90116-5.
The influence of respired gas density on ventilatory control during cycle-ergometer exercise was investigated in six healthy subjects. They underwent constant-load exercise for 10 min both at 50% and 90% of the anaerobic threshold, inhaling air for the first 5 min followed abruptly by 80% helium-20% oxygen (He-O2) for the remaining 5 min (and vice versa). The He-O2 breathing elicited no discernible effect on ventilation (VI) or mean alveolar PCO2 (PACO2) at rest or at the lower work rate. However, at the higher work rate, He-O2 breathing resulted in a clear and sustained hyperventilation in all subjects. A compensatory response to the hypocapnia, consequent to the helium-induced hyperventilation, was not evident even though all subjects demonstrated a normal ventilatory responsiveness to inhaled CO2 while in this condition. These observations suggest that turbulent airflow normally imposes a constraint on the magnitude of the hyperpnea of high-intensity exercise.
在六名健康受试者中研究了循环测力计运动期间呼吸气体密度对通气控制的影响。他们在无氧阈值的50%和90%下进行了10分钟的恒定负荷运动，前5分钟吸入空气，随后在剩余5分钟突然吸入80%氦气-20%氧气（He-O2）（反之亦然）。He-O2呼吸在休息或较低工作强度时对通气（VI）或平均肺泡PCO2（PACO2）没有明显影响。然而，在较高工作强度时，He-O2呼吸导致所有受试者出现明显且持续的通气过度。尽管所有受试者在这种情况下对吸入CO2表现出正常的通气反应性，但氦气诱导的通气过度导致的低碳酸血症的代偿反应并不明显。这些观察结果表明，湍流气流通常对高强度运动时的呼吸急促幅度施加限制。
