UBC Theses and Dissertations
Blood-gas barrier permeability in athletes with exercise-induced hypoxemia Edwards, Michael R.
The effect of incremental exercise to exhaustion on the change in pulmonary clearance rate (k) of aerosolized Technetium 99m diethylenetriaminepenta acetic acid (Tc-99m DTP A), and the relationship between k and the partial pressure of arterial oxygen (PaO₂) during heavy work, was investigated. Eleven male cyclists (age = 2 5 + 2 yrs, height = 181.3 ± 4.0 cm, mass = 80.1 ± 9.5 kg,V0₂max = 5.30 ± 0.37 1/min, mean ± SD) completed a pulmonary clearance test shortly following (39 ± 8 min) a V02max test. Resting pulmonary clearance was completed at least 24 hours before or after the exercise test. Arterial blood was sampled at rest and at one-minute intervals during exercise. Minimum PaO₂ values and maximum A-aDO₂ ranged from 73-92 Torr and 30-55 Torr respectively. No significant difference between resting k and post-exercise k for the total lung (kτ) (0.54 ± 0.19 vs. 0.57 ± 0.17, %/min, p > 0.05) was observed. Pearson-product moment correlation indicated no significant linear relationship between change in kj and minimum PaO₂ (r = -0.26, p > 0.05). These results indicate that averaged over subjects, pulmonary clearance of Tc-99m DTPA following incremental maximal exercise to exhaustion in highly trained male cyclists is unchanged. Lack of a linear relationship between pulmonary clearance rate and minimum PaO₂ during exercise suggests exerciseinduced hypoxemia occurs despite maintenance of alveolar epithelial integrity.
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