Aims: To explore possible links between sleep quality, cognitive anxiety and the effects of sleep disturbances on health, daytime functioning and quality of life, for assessment in a larger study. Hypotheses were: (a) patients with coronary artery disease have insufficient sleep as measured by self-reported sleep and by polysomnography, (b) self-reported sleep is associated with polysomnographically measured sleep, (c) reduced sleep quality is associated with physical and mental health, and interferes with quality of life as measured by means of interviews and polysomnography, (d) reduced sleep quality is associated with reduced resilience to stress.
Background: It has become increasingly evident that poor sleep with sleep initiation difficulties is an independent risk factor for cardiac events among men, and requires more attention in clinical nursing practice.
Design: Descriptive, correlative and explorative study.
Sample: Forty-four men, aged 45-70, about to undergo coronary artery bypass surgery at a Swedish University Hospital.
Research methods: Interviews and 24-hour continuous ambulatory polysomnography were performed. For the interviews, the Uppsala Sleep Inventory, Spielberger State Anxiety Scale and the Nottingham Health Profile instruments were used.
Results: Seventeen patients (38.6%) had insufficient sleep and 12 had sleep initiation difficulties. Logistic regressions revealed that reduced stage 3-4 sleep predicted poorer overall health, initiation of sleep difficulties, predicted insufficient sleep and involuntary thoughts predicted fragmented sleep. Poorer quality of life was predicted by reduced deep sleep. Independent predictors for emotional distress were sleep efficiency below 85%, fragmented sleep and a daytime nap longer than 15 minutes.
Conclusions: Objective sleep was associated with several subjective sleep variables. The results provide empirical support for significant variables included in a theoretical framework relating to sleep quality, cognitive anxiety, health and quality of life. A larger study is recommended that includes both men and women.