Effects of sleep extension on sleep duration, sleepiness, and blood pressure in college students.

OBJECTIVES

Sleep is a major lifestyle factor that may change dramatically when students begin college. Sleep duration has been shown to influence cardiometabolic health. We investigated the feasibility of sleep extension in college students to increase actigraphically measured sleep duration and the association of sleep extension with daytime sleepiness and blood pressure.

DESIGN

This was a within-participant experimental study.

SETTING

The study setting was 14-day at-home study and 3 in-lab visits.

PARTICIPANTS

The participants included in this study were healthy undergraduate students (n=53; mean age 20.5 ± 1.1 years; 70% female).

INTERVENTION

Participants maintained a habitual sleep schedule during week 1 and then were instructed to extend their sleep duration by at least 1 hour per night for week 2.

MEASUREMENTS

Sleep measures included wrist actigraphy and daytime sleepiness assessed by the Epworth Sleepiness Scale (ESS) and by daily diary. Cardiovascular measures included blood pressure (BP) and heart rate (HR). ESS, BP and HR were measured during lab visits on days 7 and 14. Multilevel modeling was used to test the effects of extension on sleep duration, daytime sleepiness, BP and HR.

RESULTS

Participants increased sleep duration during week 2 by 43.0 ± 6.2 standard error minutes per night, compared with week 1 (p<.001). Furthermore, 41 of 53 participants (77%) increased their sleep duration by >15 minutes per night (p<.001). Participants reported less daytime sleepiness on weekly ESS (p<.05) and daily log ratings (p<.001) after sleep extension; and systolic BP was significantly reduced by 7.0 ± 3.0 mmHg (p<.05).

CONCLUSION

This study demonstrates that substantive sleep extension is feasible in college students and can positively impact their sleep and cardiovascular health.