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Pulmonary gas exchange during exercise in pigs
S R Hopkins1, C M Stary, E Falor
1Department of Medicine, University of California San Diego, La Jolla, California 92093-0623, USA.shopkins@ucsd.edu
Journal of Applied Physiology (Bethesda, Md. : 1985)
|January 14, 1999
Summary
Heavy exercise increases ventilation-perfusion (VA/Q) inequality in humans, but the cause is unknown. This study introduces a pig model that mimics human exercise-induced VA/Q inequality, aiding further research into its mechanisms.
Area of Science:
- Physiology
- Exercise Physiology
- Respiratory Physiology
Background:
- Increased ventilation-perfusion (VA/Q) inequality is common in humans during heavy exercise.
- This inequality contributes to the widening of the alveolar-arterial O2 difference (A-aDO2).
- The underlying causes of exercise-induced VA/Q inequality remain largely unknown.
Purpose of the Study:
- To develop and validate a suitable animal model for studying exercise-induced VA/Q inequality.
- To investigate the physiological changes in VA/Q distribution during graded exercise in Yucatan miniswine.
Main Methods:
- Eight Yucatan miniswine were subjected to graded treadmill exercise (30%, 50%, 85% VO2 max).
- Measurements included multiple inert gases, blood gases, and metabolic data.
- Ventilation-perfusion (VA/Q) inequality was assessed using the log SD of the perfusion distribution.
Main Results:
- The alveolar-arterial O2 difference (A-aDO2) increased significantly with exercise intensity.
- Ventilation-perfusion (VA/Q) inequality, measured as log SD, increased moderately and reproducibly during exercise.
- Unlike humans, swine showed no evidence of pulmonary diffusion limitation during heavy exercise.
Conclusions:
- The Yucatan pig serves as a suitable animal model for investigating the mechanisms of exercise-induced VA/Q inequality.
- This model allows for direct examination of factors contributing to VA/Q inequality during exercise.
- Findings suggest potential differences in respiratory adaptations between pigs and humans during intense physical activity.