Pulmonary gas exchange does not worsen during repeat exercise in women

The purposes were to determine (1) if repeat exercise worsens pulmonary gas exchange in women, and, (2) if the level of pulmonary edema obtained in these same women is related to the gas exchange impairment during exercise. Fourteen women (27 ± 4 yrs; maximal oxygen uptake = 3.12 ± 0.42 L/min) with minimal arterial PO₂ (PaO₂) ranging from 76 to 104 mmHg with a maximal alveolar-arterial PO₂ difference (AaDO₂) ranging from 7 to 35 mmHg performed three bouts of near-maximal exercise on a cycle ergometer (236 ± 27 W) for 5 min each with 10 min of rest between sets. Cardiorespiratory parameters and oxygenation were measured at rest, throughout exercise and recovery. Chest radiographs were obtained before and 30 min after the interval training session (see Respir Physiol Neurobiol, 153 (2006) 181-190). Repeat exercise did not affect pulmonary gas exchange between sets 1 and 3 (change in PaO₂ = 3 ± 2 mmHg; change in AaDO₂ = 1 ± 2 mmHg P > 0.05). Arterial PCO₂ decreased by 4 ± 2 mmHg (P < 0.05) between sets 1 and 2, which did not reduce further in set 3. The level of PaO₂ or AaDO₂ was not related to the change in edema score or the post-exercise edema score (P > 0.05). In conclusion, pulmonary gas exchange is not worsened in women during interval training despite the mild edema triggered by exercise.