Density-dependent airflow and ventilatory control during exercise.

S A Ward; B J Whipp; C S Poon

doi:10.1016/0034-5687(82)90116-5

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PubMed · 6815752

Density-dependent airflow and ventilatory control during exercise.

S A Ward·B J Whipp·C S Poon

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Abstract

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.

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Carbon Dioxide Helium Homeostasis Humans Oxygen Physical Exertion Pulmonary Ventilation Respiration Respiratory Physiological Phenomena Rest Journal Article Research Support, Non-U.S. Gov't

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S A Ward, B J Whipp, C S Poon. 1982. Density-dependent airflow and ventilatory control during exercise.. https://doi.org/10.1016/0034-5687(82)90116-5

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