title: Sleep disturbance during ambulatory blood pressure monitoring of hypertensive patients.
abstract: BACKGROUND: Hypertensive patients who fail to exhibit a normal fall in blood pressure at night may have a greater risk of target-organ damage. Sleep, with associated cessation of physical activity, is the principal determinant of nocturnal blood pressure 'dip'. OBJECTIVE: To ascertain whether hypertensive patients, who experience the discomfort of higher cuff-inflation pressures during ambulatory blood pressure monitoring, experience more interference with sleep, manifested by greater nocturnal physical activity. DESIGN: A retrospective case- control study. METHODS: Subjects were selected from a database of 475 patients who had undergone simultaneous 24 h ambulatory blood pressure monitoring and monitoring of physical activity with a wrist-mounted piezoelectric accelerometer. Sixty-one hypertensives (average daytime systolic blood pressure >/= 150 mmHg) were age matched to 61 subjects with average daytime systolic blood pressures </= 130 mmHg. RESULTS: Average daytime blood pressure was 161 +/- 8/95 +/- 10 mmHg in hypertensives and 123 +/- 6/81 +/- in normotensives; night-time blood pressures were 139 +/- 13/82 +/- 11 and 103 +/- 10/64 +/- 7 mmHg, respectively. Hypertensives exhibited higher nocturnal physical activity during sleeping time (2.46 +/- 2.16 versus 1.66 +/- 0.86 activity units, P =0.009) and from 0200 to 0500 h (2.43 +/- 3.12 versus 1.32 +/- 1.16 units, P = 0.011). Hypertensives fell asleep later (2359 h +/- 66 min versus 2335 h +/- 50 min, P = 0.027) slept less (8.00 +/- 1.27 h versus 8.26 +/- 1.08, NS) and had more episodes of nocturnal disturbance (4.74 +/- 3.42 versus 3.36 +/- 2.56, P = 0.004) than did normotensives. In addition, hypertensive subjects had a smaller nocturnal percentage rising single quote, left (low)dip' in blood pressure than did normotensive subjects (14 +/- 7/14 +/- 8 versus 16 +/- 7/21 +/- 7 mmHg, P = 0.03/P < 0.0001). CONCLUSIIONS: Higher cuff-inflation pressures experienced by hypertensive patients are associated with greater nocturnal physical activity and probably associated with poorer quality of sleep. Disturbance of sleep could influence 'dipper' status.
authors.affiliation: Department of Pharmacology and Therapeutics, University College, Cork, Ireland.
authors.initials: AC
authors.lastname: Leary
authors.initials: MB
authors.lastname: Murphy