Sleep disorders are known to increase the risk of hypertension, yet few studies have investigated the relation between sleep disorders and morning blood pressure (BP). This study aimed to determine, whether the morning BP is associated with sleep quality and sleep-disordered breathing. A total of 144 hypertensive patients were included in this cross-sectional study. Each subject underwent anthropometric measurements, biochemical testing, 24-h ambulatory BP monitoring, and polysomnography (PSG). Sleep quality and sleep-disordered breathing were determined by PSG parameters of sleep architecture and sleep respiratory. There were no significant differences between subjects with and without morning hypertension in the parameters of sleep architecture and sleep respiratory. In multiple regression analysis, morning BP was independently associated with night-time BP and morning BP surge, but not with the parameters of sleep architecture and sleep respiratory. Further analysis showed that both night-time BP and morning BP surge were independently associated with the sleep respiratory parameters. In conclusion, sleep-disordered breathing might indirectly affect the morning BP by elevated night-time BP, yet neither poor sleep quality nor sleep-disordered breathing was major determinants of elevated morning BP in hypertensive patients.
Keywords: Polysomnography; morning blood pressure; night-time blood pressure; sleep architecture; sleep quality; sleep-disordered breathing.