Abstract
STUDY OBJECTIVES: Exercise capacity is impaired in obstructive sleep apnea (OSA). There are conflicting reports on the effect of continuous positive airway pressure (CPAP) on maximal exercise capacity. The objective of this review was to determine if there is a change in exercise capacity and anaerobic threshold following CPAP treatment in OSA patients. METHODS: We conducted a systematic review and meta-analyses to summarize the changes in peak rate of oxygen uptake (V̇O₂ peak) or maximum rate of oxygen uptake (V̇O2 max) and anaerobic threshold (AT) during cardiopulmonary exercise testing following CPAP intervention in patients with OSA. A systematic literature review was conducted to identify published literature on markers of V̇O₂ peak, V̇O₂ max, and AT pre- vs post-CPAP using a web-based literature search of PubMed/MEDLINE, Embase, CINAHL, and Cochrane review (CENTRAL) databases. Two independent reviewers screened the articles for data extraction and analysis. RESULTS: The total search of all the databases returned 470 relevant citations. Following application of eligibility criteria, 6 studies were included in the final meta-analysis for V̇O₂ peak, 2 studies for V̇O₂ max, and five studies for AT. The meta-analysis showed a mean net difference in V̇O₂ peak between pre- and post-CPAP of 2.69 mL·kg(-1)·min(-1), P = .02, favoring treatment with CPAP. There was no difference in V̇O₂ max or AT with CPAP treatment (mean net difference 0.66 mL·kg(-1)·min(-1) [P = .78] and -144.98 mL·min(-1) [P = .20] respectively). CONCLUSIONS: There is a paucity of high-quality studies investigating the effect of CPAP on exercise capacity. Our meta-analysis shows that V̇O₂ peak increases following CPAP treatment in patients with OSA, but we did not observe any change in V̇O₂ max or AT. Our findings should be considered preliminary and we recommend further randomized controlled trials to confirm our findings and to clarify the peak and maximum rates of oxygen uptake adaptations with CPAP therapy.