Abstract
There is presently no precise way to determine ventilatory capacity for a given individual during exercise; however, this information would be helpful in evaluating ventilatory reserve during exercise. Using schematic representations of maximal expiratory flow-volume curves and individual maximal expiratory flow-volume curves from four subjects, we describe a technique for estimating ventilatory capacity. In these subjects, we measured maximal expiratory flow-volume loops at rest and tidal flow-volume loops and inspiratory capacity (IC) during submaximal cycle ergometry. We also compared minute ventilation (V̇E) during submaximal exercise with calculated ventilatory maxima (V̇E(max Cal)) and with maximal voluntary ventilation (MVV) to estimate ventilatory reserve. Using the schematic flow-volume curves, we demonstrated the theoretical effect of maximal expiratory flow and lung volume on ventilatory capacity and breathing pattern. In the subjects, we observed that the estimation of ventilatory reserve with use of V̇E/V̇E(max Cal) was most helpful in indicating when subjects were approaching maximal expiratory flow over a large portion of tidal volume, especially at submaximal exercise levels where V̇E/V̇E(max Cal) and V̇E/MVV differed the most. These data suggest that this technique may be useful in estimating ventilatory capacity, which could then be used to evaluate ventilatory reserve during exercise.
Original language | English (US) |
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Pages (from-to) | 2016-2022 |
Number of pages | 7 |
Journal | Journal of applied physiology |
Volume | 74 |
Issue number | 4 |
DOIs | |
State | Published - 1993 |
Keywords
- airflow limitation
- breathing pattern
- lung mechanics
- lung volumes
- maximal ventilation
- ventilatory reserve
ASJC Scopus subject areas
- Physiology
- Physiology (medical)