Repetitive exposure to shortened sleep leads to blunted sleep-associated blood pressure dipping

Background: Blood pressure (BP) dips at night during sleep in healthy individuals but in disturbed sleep, dipping is blunted. However, the impact of chronic insufficient sleep duration, with limited intermittent recovery sleep, on BP dipping is not known. The objective of this study was to examine, in a controlled experimental model, the influence of chronic sleep restriction on BP patterns at night and during the day. Method: In a highly controlled 22-day in-hospital protocol, 45 healthy participants (age 322 years; BMI 241kg/m(2); 22 men and 23 women) were randomly assigned to one of two conditions: repeated sleep restriction (4h of sleep/night from 0300 to 0700 h for three nights followed by recovery sleep of 8h, repeated four times in succession) or a sleep control group (8h/night from 2300 to 0700 h). Results: Beat-to-beat BP and polysomnography were recorded and revealed that sleep-associated DBP dipping was significantly blunted during all four blocks of sleep restriction (P=0.002). Further, DBP was significantly increased for the whole day during the first, second, and fourth block of sleep restriction (all P<0.01), and SBP was significantly increased for the whole day during the first block of sleep restriction. Conclusion: Repeated exposure to significantly shortened sleep blunts sleep-associated BP dipping, despite intermittent catch-up sleep. Individuals frequently experiencing insufficient sleep may be at increased risk for hypertension due to repetitive blunting of sleep-associated BP dipping, and resultant elevations in average circadian BP.