Cardiovascular capacity in adults with obstructive sleep apnoea

BACKGROUND: Obstructive sleep apnoea (OSA) patients have a decreased exercise capacity. Potential cardiovascular capacity in patients with OSA with different severity with-out known cardiovascular disease has not been described. OBJECTIVE: To evaluate impaired potential exercise cardiovascular capacity during cardiopulmonary exer-cise testing (CPET) in OSA patients and to compare car-diovascular performance reaction with different severity during graded exercise stages.DESIGN: All participants were accompanied without car-diovascular disease, especially hypertension and arrhyth-mia. Parameters of different stages were compared between subjects with and without OSA, and among OSA patients with varied severity.RESULTS: Despite having significantly higher peak exercise diastolic blood pressure (DBP) and ventilatory equivalent for CO2 (EQCO2), patients with OSA had a lower peak oxygen uptake (VO2), heart rate (HR), heart rate recovery (HRR) and respiratory reserve (BR) than normal subjects. Furthermore, significant correlations were found between VO2, DBP, EQCO2, HRR, BR and the apnoea-hypopnea index. In severe OSA, there was a greater difference in HR and HRR during the anaerobic threshold stages.CONCLUSIONS: OSA patients demonstrate reduced potential cardiovascular capacity, even without docu-mented cardiovascular disease. Patients with severe OSA develop impaired exercise capacity at early stage during exercise. These data point to exaggerated haemodynamic response to graded exercise and delayed post-exercise car-diovascular response recovery in OSA patients. CPET can be a supplement for assessment of OSA severity.