Acute social jetlag augments morning blood pressure surge: a randomized crossover trial

Abstract

Although social jetlag (SJL) is generally considered a chronic condition, even acute SJL may have unfavorable effects on the cardiovascular system. We focused on the acute effects of SJL on morning blood pressure (BP) surge. This randomized crossover trial recruited 20 healthy men. In the SJL trial, participants delayed their bedtime by three hours on Friday and Saturday nights. Participants in the control (CON) trial implemented the same sleep-wake timing as on weekdays. Pre- and post-intervention measurements were performed to evaluate resting cardiovascular variables on Friday and Monday mornings, respectively. The ambulatory BP was automatically measured during the sleep and awake periods for 2 h after the participant woke up at night before pre- and post-intervention measurements. SJL (average mid-sleep time on weekends - average mid-sleep time on weekdays) occurred only in the SJL trial (SJL: 181 ± 24 min vs. CON: 8 ± 47 min). Carotid-femoral pulse wave velocity (cfPWV) and morning BP surge on Monday in the SJL trial were significantly higher than those on Friday in the SJL trial (cfPWV: P = 0.001, morning BP surge: P < 0.001), and those on Monday in the CON trial (cfPWV: P = 0.007; morning BP surge: P < 0.001). Furthermore, a significant positive correlation was found between ΔcfPWV and Δmorning BP surge (R = 0.587, P = 0.004). These results suggest that even acute SJL augments morning BP surge. This phenomenon may correspond to increased central arterial stiffness.State the details of Clinical Trials: Name: Effect of acute social jetlag on risk factors of lifestyle-related diseases. URL: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000053204 . Unique identifier: UMIN000046639. Registration date: 17/01/2022.

Keywords: Central arterial stiffness; Morning blood pressure surge; Social jetlag.

Fig. 1

Time course of ambulatory systolic blood pressure (line chart) and physical activity (vertical bar chart) for 2 h before and after the awake time (n = 14). A vertical bar line means the awakening point as zero. Line charts show the time course of ambulatory systolic blood pressure as follows: open triangle (△): CON trial on Friday, open circle (○): CON trial on Monday, closed triangle (▲): SJL trial on Friday, closed circle (●): SJL trial on Monday. Vertical bar charts show as follows: white bar: CON trial on Friday, white bar with a black dot: CON trial on Monday, black bar: SJL trial on Friday, black bar with a white dot: SJL trial on Monday. CON, control trial; SBP, systolic blood pressure; SJL, social jetlag trial. Values are presented as mean ± standard deviation. ^*Significantly different from Friday in the SJL trial at the same point (P < 0.05). ^†Significantly different from Monday in the CON trial at the same point (P < 0.05)

Fig. 2

Central arterial stiffness (a), morning blood pressure surge (b) on Friday and Monday morning in both trials (n = 14). White bar: Friday. Black bar: Monday. BP, blood pressure; cfPWV, carotid-femoral pulse wave velocity; CON, control trial; SJL, social jetlag trial. Values are presented as mean ± standard deviation. ^*Significantly different from Friday in the SJL trial (P < 0.05). ^†Significantly different from Monday in the CON trial (P < 0.05)

Fig. 3

Association between changes in central arterial stiffness and morning blood pressure surge (a) and changes in sympathetic nerve activity and central arterial stiffness (b) or morning blood pressure surge (c) from Friday to Monday (CON trial: n = 14, SJL trial: n = 14). Δ means the change from Friday to Monday in each trial. Open circle (○): CON trial. Closed circle (●): SJL trial. The open and closed circles of each participants were connected with thin dot line. BP, blood pressure; cfPWV, carotid-femoral pulse wave velocity; CON, control trial; LF-SBP, low-frequency systolic blood pressure; SJL, social jetlag trial