Intention Setting to Improve Sleep Practices: The Impact on Sleep and Theory of Planned Behaviour Variables; a Randomised Control Trial in Undergraduate Students.

Background: This study investigated whether providing sleep hygiene advice combined with intention setting to improve sleep increased sleep hygiene, sleep period, and advanced bedtime compared with a wellbeing intervention.

Method: The intervention for this randomised control trial was delivered in a single online session to undergraduate students. Participants were randomised to either the sleep intervention, an intervention for mental wellbeing, or a control condition. Participants in the sleep and wellbeing conditions watched a video about healthy sleep habits and healthy mental wellbeing, respectively, and set three intentions to improve this outcome. Theory of planned behaviour variables were assessed pre- and post-intervention, and sleep variables were assessed pre-intervention and at 1-week follow-up (n = 128 included at the follow-up).

Results: Sleep hygiene scores were significantly lower for the sleep intention setting group compared with the control group post-intervention, reflecting a small effect size (Cohen's d .45). Following the sleep intervention, there was no difference in sleep period or bedtime relative to the control group. Setting intentions did significantly increase participants' intention to use strategies to improve their sleep, but change in intention score was not associated with post-intervention attitude, control belief strength, or power in relation to sleep.

Conclusion: Setting intentions to improve sleep results in improved sleep hygiene compared to setting no intentions. However, improved sleep hygiene does not transfer to an increased sleep period or earlier bedtimes, nor does it change attitude and perceived behavioural control. Future studies should consider the moderating role of environmental barriers to intention setting.