Impaired cerebral oxygenation and exercise tolerance in patients with severe obstructive sleep apnoea syndrome

Abstract

Impaired cerebral blood blow during wakefulness at rest as well as reduced exercise tolerance have been reported in severe obstructive sleep apnoea (OSA) patients. Impaired cerebral oxygenation can contribute to reduced exercise performance. We hypothesized that i) OSA patients show impaired cerebral hemodynamics pattern during exercise together with reduced exercise tolerance and ii) continuous positive airway pressure (CPAP) treatment improves these alterations in cerebral oxygenation. Fifteen OSA patients and 12 healthy matched controls performed a maximal cardiopulmonary exercise test before and after 8 weeks of CPAP treatment or control period. Prefrontal cortex and muscle oxygenation were assessed by near-infrared spectroscopy. Reduced prefrontal cortex oxygen extraction and total blood volume (i.e. lower increase in deoxyhemoglobin ([HHb]) [1.76±1.57 vs 3.43±2.08 µmol; p This study demonstrates that cerebrovascular response to exercise is altered in OSA and likely contributes to exercise intolerance in these patients. Prefrontal cortex oxygenation and exercise tolerance are not significantly improved following 8 weeks of CPAP treatment.