Exercise Intolerance in Untreated OSA: Role of Pulmonary Gas Exchange and Systemic Vascular Abnormalities.

Background: Reduced exercise capacity has been reported previously in patients with OSA hypopnea syndrome (OSAHS), although the underlying mechanisms are unclear.

Research Question: What are the underlying mechanisms of reduced exercise capacity in untreated patients with OSAHS? Is there a role for systemic or pulmonary vascular abnormalities?

Study Design And Methods: This was a cross-sectional observational study in which 14 patients with moderate to severe OSAHS and 10 control participants (matched for age, BMI, smoking history, and FEV) underwent spirometry, incremental cycle cardiopulmonary exercise test (CPET) with arterial line, resting echocardiography, and assessment of arterial stiffness (pulse wave velocity [PWV] and augmentation index [AIx]).

Results: Patients (age, 50 ± 11 years; BMI, 30.