Poor sleep quality, stress status, and sympathetic nervous system activation in nondipping hypertension

It has been reported that poor sleep quality is associated with nondipping hypertension, but the underlying mechanisms were not reported. This study was carried out to evaluate whether poor sleep quality is associated with stress status and sympathetic nervous system activation in nondippers.

A total of 307 Chinese essential hypertensive patients were defined as dippers or nondippers by ambulatory blood pressure monitoring. Sleep quality was assessed by Pittsburgh Sleep Quality Index (PSQI), and stress status was assessed by Perceived Stress Scale (PSS). The levels of epinephrine and norepinephrine were examined to investigate the underlying mechanisms.

A total of 204 (66.4%) and 103 cases (33.6%) were found to be dippers and nondippers, respectively. Nondippers were with poorer sleep quality (P<0.05), more stressful status (P<0.05), and with an increased activity of sympathetic nervous system (P<0.01). The decline of systolic BP (SBP) and diastolic BP (DBP) at night was inversely related with the PSQI score (r=-0.469, P<0.01 and r=-0.421, P<0.01), PSS score (r=-0.432, P<0.01 and r=-0.404, P<0.01), epinephrine (r=-0.304, P<0.05 and r=-0.293, P<0.05), and norepinephrine (r=-0.321, P<0.05 and r=-0.357, P<0.05). Multiple logistic regression analyses showed that older age [odds ratio (OR): 1.69; 95% confidence interval (CI): 1.22-2.43], PSQI score (OR: 2.78; 95% CI: 1.65-6.87), and PSS score (OR: 2.43; 95% CI: 1.56-5.93) were independently correlated with the nondipping pattern.

Poor sleep quality and stressful status were closely associated with higher activation of sympathetic nervous system, and they are independent predictors of nondipping hypertension.