[Improvement of cardiopulmonary exercise capacity in patients with obstructive sleep apnea syndrome under CPAP therapy].

Background And Purpose: Obstructive sleep apnea syndrome (OSAS) is regarded as a cardiovascular risk factor. Therefore, cardiopulmonary exercise capacity in patients with OSAS before and under treatment with continuous positive airway pressure (CPAP) was investigated.

Patients And Methods: Cardiopulmonary exercise capacity was investigated in 36 patients with untreated OSAS using spiroergometry. A follow-up after at least 6 months was performed in 17 of these patients being treated with CPAP and in eight CPAP-neglecting patients, who served as controls.

Results: Maximum oxygen uptake ( O(2max)) was significantly reduced in all 36 patients with untreated OSAS (17.68 +/- 6.1 ml/min/kg) compared with reference values (30.72 +/- 4.9 ml/min/kg; p < 0.001). After an average of 305.7 +/- 104.8 nights of CPAP therapy, O(2max) rose from 15.33 +/- 4.8 to 18.53 +/- 6.9 ml/min/kg, whereas O(2max) remained unchanged in controls. Further spirometric parameters of exercise capacity as well as arterial blood pressure were also significantly improved under CPAP therapy.

Conclusion: Cardiopulmonary exercise capacity is markedly reduced in patients with OSAS. Long-term CPAP therapy leads to a significant improvement of reduced cardiopulmonary exercise capacity in these patients.