The Effects of Ambulatory Blood Pressure Monitoring on Sleep Quality in Men and Women With Hypertension: Dipper vs. Nondipper and Race Differences

BACKGROUND: The nondipping circadian blood pressure (BP) profile is associated with both poor sleep quality and increased cardiovascular risk. The present study aimed to clarify the potential confounding effects of 24-hour ambulatory blood pressure monitoring (ABPM) used to characterize the circadian BP profile by assessing its impact on sleep quality. METHODS: Participants were 121 middle-aged men and women with untreated hypertension (age = 46 ± 8 years; 43% women; 45% African-American). Subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index. Wrist actigraphy was used to measure sleep quality objectively as sleep efficiency (SE) and total sleep time (TST) on 7 consecutive non-ABPM days (baseline) and 3 subsequent 24-hour ABPM days. RESULTS: Average ambulatory BP was 137.2 ± 10.8/84.3 ± 8.5 mm Hg during the day and 119.6 ± 12.4/69.5 ± 9.8 mm Hg at night. Using the criterion of <10% dip in systolic BP (SBP) to define nondippers, there were 40 nondippers (SBP dip = 7.3 ± 2.6%) and 81 dippers (SBP dip = 15.5 ± 3.4%). There was no effect of time on SE or TST over non-ABPM and ABPM days, suggesting that ABPM does not adversely affect sleep quality. Sleep quality was generally poorer (lower SE) in nondippers compared with dippers (P = 0.033), but differences were independent of whether or not participants were undergoing 24-hour ABPM. African-American race (P = 0.002) was also associated with lower SE. CONCLUSION: Sleep quality generally appears to be poor in men and women with untreated hypertension and especially among African-Americans. Importantly, for both dippers and nondippers, we found no evidence that ABPM had an adverse effect on sleep quality.