Hypoxia following voluntary hyperventilation during exercise in man
| Autor: | K.B. Saunders, A. R. C. Cummin, R. J. Telford |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Pulmonary and Respiratory Medicine
Adult Male Adolescent Physiology Physical exercise Models Biological Hypocapnia Hyperventilation medicine Humans Hypoxia Exercise Central chemoreceptors business.industry Pulmonary Gas Exchange Respiration Healthy subjects Hypoxia (medical) Carbon Dioxide medicine.disease Control of respiration Anesthesia Breathing medicine.symptom Blood Gas Analysis business Mathematics |
| Zdroj: | Respiration physiology. 84(2) |
| ISSN: | 0034-5687 |
| Popis: | The importance of carbon dioxide in the control of ventilation during exercise was tested by emptying CO 2 stores by voluntary hyperventilation. Healthy subjects were studied after 3 min hyperventilation down to an end-tidal P CO 2 of about 20 mmHg on a background of steady exercise at 75 W. Control runs were performed when the hyperventilation was made isocapnic by the addition of CO 2 . Following hypocapnic hyperventilation, there was a period when ventilation fell below control and this was accompanied by a fall in end-tidal P O 2 (minimum 48 mmHg) and oximeter reading (minimum 73%). Ventilation rapidly returned to baseline following isocapnic hyperventilation and hypoxia was not seen. A mathematical simulation suggested that brain P CO 2 recovered more slowly than arterial P CO 2 and that at the times that ventilation was depressed central chemoreceptor P CO 2 would have been low. We conclude that CO 2 provides a crucial drive for maintaining adequate ventilation during steady exercise and that the central chemoreceptor may be involved. |
| Databáze: | OpenAIRE |
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