Plain language summary
Insufficient sleep is a widespread problem. For adults between 18 and 64 years, the National Sleep Foundation generally recommends a range of nightly sleep duration from 7 to 9 hours. The aim of this study was to test a self-regulatory intervention based on mental contrasting with implementation intentions (MCII) against the effects of sleep hygiene information only. This study was a single-blinded, randomised controlled trial with daily/nightly assessments in a baseline-week and analog daily/nightly assessments in a post-intervention week. Participants were randomly assigned to one of the two groups. Results indicated an increase in sleep quality and subjective (but not objective) sleep duration from baseline to post-intervention period. Additionally, regarding subjective stress, associations with daily sleep parameters were largely confirmed. Authors conclude that future research should include booster sessions and evaluate MCII effects in the longer run. Furthermore, a better understanding of the causes regarding insufficient sleep among specific target groups and their degree of controllability is required to develop individually targeted interventions.
Abstract
Mental contrasting with implementation intentions (MCII) has been successfully applied to improve health-related behaviors (e.g. exercise). We explored its effectiveness to improve sleep outcomes beyond effects of sleep hygiene (SH) information, and investigated associations with stress. Eighty university employees (mean age: 29.6, SD = 4.5) were randomized to either a MCII + SH or a SH-only condition. During a baseline-week and a post-intervention week, sleep duration (Fitbit Alta and self-report), sleep quality, and stress were assessed daily and saliva was collected to assess the cortisol awakening response (CAR). In total, self-reported sleep quality and duration increased, but there was no meaningful condition*week interaction for sleep parameters or CAR. Higher average stress was associated with shorter sleep duration and lower sleep quality. Within-person, days with higher stress were followed by nights with lower sleep quality. Despite overall improvements, effects of MCII were not confirmed. MCII might be less effective to improve behaviors which are less controllable.
Methodological quality
Jadad score
:
3
Allocation concealment
:
Yes
