Impact of obstructive sleep apnoea on nocturnal blood pressure: mechanisms and treatment responses - a narrative review.

Nocturnal blood pressure (BP) is a major determinant of cardiovascular risk. In obstructive sleep apnoea (OSA), abnormal nocturnal BP patterns, particularly nondipping and nocturnal hypertension, are common and contribute to excess cardiovascular risk. However, this association remains insufficiently integrated into routine clinical practice, as BP assessment still relies largely on office or home measurements and ambulatory BP monitoring is underused. This narrative review summarises current evidence on the physiological regulation of nocturnal BP, the mechanisms by which OSA disrupts nocturnal BP control, the epidemiology and prognostic relevance of abnormal nocturnal BP patterns in OSA, and the effects of available therapies. Continuous positive airway pressure (CPAP) has the strongest evidence base and lowers nocturnal BP modestly on average, with greater effects in patients with uncontrolled or resistant hypertension and with better treatment adherence. By contrast, evidence for non-CPAP therapies, including mandibular advancement devices, supplemental oxygen, hypoglossal nerve stimulation and upper-airway surgery, remains limited and less consistent. In summary, nocturnal BP abnormalities are common, clinically important and frequently overlooked in OSA. Greater use of ambulatory BP monitoring and more precise identification of patients most likely to benefit from targeted treatment may improve cardiovascular risk stratification and management in OSA.