Abstract:
Sleep deprivation is a significant problem in the modern workplace and has negative consequences for employee health. There has been recent emphasis on the need to better understand principles of selfcontrol and the study of sleep-related behaviour provides the perfect avenue to enlighten this area. Moreover, whilst the effects of sleep deprivation are becoming better understood, there remains few strategies to help non-clinical populations to sleep better. The focus of this thesis was on identifying factors associated with sleep loss in employees and developing efficient psychological strategies to improve sleep patterns in these workers. A sleep self-regulation model was developed to guide the research. Measures included the Pittsburgh Sleep Quality Index (PSQI) and the Copenhagen Psychosocial Questionnaire. In the first study, analysis of the baseline data from 91 daytime employees indicated that giving sleep a high priority was associated with higher levels of pre-sleep arousal which in turn was linked with greater sleep difficulty (shown by higher PSQI scores). Work-goal motivations (personal commitments to achieving goals at work) were associated with a faster time to sleep and improvement in pre-sleep arousal yet poorer sleep quality and greater sleep difficulty. Results from mixed model analyses of daily reports of sleep behaviour collected over the remaining 10 days suggested that (1) higher cognitive demands at work were associated with later time of lights out (beginning to try and go to sleep) that night; (2) higher emotional demands at work predicted both an earlier time of lights out that night and an earlier time of waking the next morning; and (3) positive emotions arising from work-related events and finding work to be meaningful were associated with better sleep quality that night. These results supported the need to utilise self-regulation techniques to protect sleep from being influenced by external demands and internal reactions to these demands. The aim of the next three studies (two intervention development studies and a larger randomised controlled trial) was to develop a sleep self-regulation intervention that could be delivered efficiently to the wider non-clinical population. The final randomised controlled trial assessed the efficacy of four mental imagery techniques: (1) imagery focused on arousal reduction techniques; (2) imagery incorporating implementation intentions (a strategy designed to link specified behaviour with the anticipated context) for sleep-related behaviour; (3) a combination of imagery using arousal reduction and implementation intention strategies; or (4) a condition where participants were asked to imagine their typical post work activities. A total of 104 participants completed an online, daily diary of sleep behaviours and, at baseline and Day 21, an online questionnaire. Improvement in several sleep-related indicators occurred across all groups. Moreover, relative to groups not using the implementation intentions imagery, groups using this imagery exhibited a greater reduction in negative sleep habits, greater sleep-related self-efficacy, and greater improvements in the sleep-related actions targeted in the imagery exercise. Mixed model analyses also suggested greater improvements in daily perceptions of sleep quality and time to sleep from using the implementation intentions imagery. These studies represent one of the first examples of the application of implementation intentions to sleep-related behaviour. The importance of time cues for instigating behavioural change, including behaviours that are strongly habitual (e.g. time of lights out), are also highlighted. In summary, results point to the utility of an empirically based intervention delivered online at low cost and high convenience to a population of busy employees.