Sj. Rosansky et al., THE RELATIONSHIP BETWEEN SLEEP-DEPRIVATION AND THE NOCTURNAL DECLINE OF BLOOD-PRESSURE, American journal of hypertension, 9(11), 1996, pp. 1136-1138
Blood pressure (BP) has a circadian pattern with a 10% to 15% drop in
systolic and diastolic BP comparing nighttime and daytime averages. Th
e mechanism and the ''reason'' for the decline of nocturnal blood pres
sure has not been described. If the nocturnal decline is a restorative
physiologic process we reasoned that sleep deprivation would increase
the nocturnal drop. Thus, we tested the hypothesis that there is a co
mpensatory decline in nocturnal sleep blood pressure after a period of
nocturnal sleep deprivation. Twenty-four house staff personnel (normo
tensive and not taking any BP medications) with a mean age of 29.3 yea
rs were recruited for this study (13 men and 11 women). Subjects were
randomly assigned to have 24-h BP monitoring after being sleep deprive
d (on call with 3 +/- 1.3 h of sleep) or after a normal night's sleep
(7.3 +/- 0.8 h). There was no significant difference in hours asleep o
r time to bed or time awake for both 24-h studies. Subjects had simila
r activities for both monitoring intervals. The percent change in day
awake versus night asleep mean values for systolic BP, diastolic BP, a
nd mean arterial pressure for sleep deprived and normal night's sleep
intervals were compared using paired t tests. None of these paired par
ameters were significantly different despite a subjectively ''deeper''
sleep postcall. In conclusion, sleep deprivation does not appear to r
esult in a compensatory decline in nocturnal blood pressure. Thus, the
''reason'' for the normal nocturnal decline in blood pressure remains
to be explored.