Effects of deep breaths on subsequent ventilation in man during rest and exercise
| Autor: | S. S. D. Fernando, K. B. Saunders |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Adult
Male Physiology Rest Vital Capacity Inspiratory Capacity Breathing pattern Carbon dioxide blood Humans Medicine Expiration Exercise physiology Residual volume Exercise Hypocapnia business.industry Carbon Dioxide Expiratory Reserve Volume Anesthesia Respiratory Mechanics Reflex Female Ventilatory drive business Research Article |
| Zdroj: | The Journal of Physiology. 481:479-486 |
| ISSN: | 0022-3751 |
| DOI: | 10.1113/jphysiol.1994.sp020456 |
| Popis: | 1. We examined the effects of twenty-four to thirty inspiratory capacity (IC), expiratory capacity (EC) and vital capacity (VC) breaths on subsequent breathing pattern in five normal subjects at rest. 2. During IC breaths and following EC and VC breaths at rest, end-tidal CO2 pressure (PET,CO2) fell by 7.5, 8.5 and 9.5 mmHg, respectively. In the group analysis significant inhibition of ventilation of 1.5 l min-1 was seen after the IC breath but not after EC or VC breaths. 3. We repeated the study with five normal subjects under conditions of higher ventilatory drive, namely 50 W exercise (one subject was common to both groups). 4. During exercise, the drop in PET,CO2 was smaller (4.0, 3.5 and 4.0 mmHg, respectively, with IC, EC and VC breaths) but ventilation was inhibited to a greater extent. Ventilatory undershoot was seen after all three types of deep breaths. 5. We propose that the expiration to residual volume in EC and VC breaths abolished the hypocapnic inhibition of ventilation at rest, possibly by a deflation reflex which was not sufficiently powerful to overcome the ventilatory undershoot during exercise. Our results also support the view that the slope of the CO2 response curve is steeper near the control point during exercise. |
| Databáze: | OpenAIRE |
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