Influence of quality of sleep on the nocturnal decline in blood pressure during ambulatory blood pressure monitoring.

OBJECTIVE To assess the influence of the quality of sleep on the nocturnal physiological drop in blood pressure during ambulatory blood pressure monitoring. METHODS We consecutively assessed ambulatory blood pressure monitoring, the degree of tolerance for the examination, and the quality of sleep in 168 patients with hypertension or with the suspected "white-coat" effect. Blood pressure fall during sleep associated with a specific questionnaire and an analogical visual scale of tolerance for ambulatory blood pressure monitoring were used to assess usual sleep and sleep on the day of examination. Two specialists in sleep disturbances classified the patients into 2 groups: those with normal sleep and those with abnormal sleep. RESULTS Fifty-nine (35 %) patients comprised the abnormal sleep group. Findings regarding the quality of sleep on the day of ambulatory blood pressure monitoring as compared with those regarding the quality of sleep on a usual day were different and were as follows, respectively: total duration of sleep (-12.4 +/- 4.7 versus -42.2 +/- 14.9 minutes, P=0.02), latency of sleep (0.4 +/- 2.7 versus 17 +/- 5.1 minutes, P<0.001), number of awakenings (0.1 +/- 0.1 versus 1.35 +/- 0.3 times, P<0.001), and tolerance for ambulatory blood pressure monitoring (8 +/- 0.2 versus 6.7 +/- 0.35, P=0.035). An abnormal drop in blood pressure during sleep occurred in 20 (18%) patients in the normal sleep group and in 14 (24%) patients in the abnormal sleep group, P=0.53. CONCLUSION Ambulatory blood pressure monitoring causes sleep disturbances in some patients, and a positive association between quality of sleep and tolerance for the examination was observed.