Psychosocial Factors, Sleep Disturbances, and Physical Activity in Patients After Cardiac Surgery

Cardiac surgery is one of the most effective tools for managing heart disease, the leading cause of death globally. After cardiac surgery, physical activity is key to improving patients’ quality of life and decreasing mortality, but more than 40% of post-surgical cardiac patients are physically inactive. Cardiac patients’ physical activity has been associated with anxiety, depression, self-efficacy, social support, and socioeconomic status (all psychosocial factors) and sleep disturbances. Consequently, greater understanding of the combined effects of psychosocial factors and sleep disturbances on physical activity will contribute to efforts to enhance patients’ physical activity after cardiac surgery. This research was conducted to examine relationships among psychosocial factors, sleep disturbances, and physical activity in patients who had undergone cardiac surgery. This dissertation first examines the influence of psychosocial factors and sleep disturbances on physical activity as well as the potential mediating role of sleep disturbances in these relationships. It then focuses on identifying the effects of daily sleep disturbances on daily physical activity. For these studies, 33 patients who had undergone cardiac surgery were recruited from a Chicago medical center and using an online recruitment site. Psychosocial factors, sleep disturbances, and physical activity were measured using an online survey, and sleep disturbances and physical activity were also measured using an ActiGraph for 7 days and nights. Regression analyses and structural equation modeling were applied to examine factors influencing physical activity and sleep disturbances’ mediating role between psychosocial factors and physical activity. In addition, mixed-effects model analyses were used to examine the effect of daily sleep disturbances on daily physical activity. Results showed that self-efficacy, sleep duration, sleep efficiency, and wake after sleep onset were predictors for physical activity after cardiac surgery; however, sleep disturbances played no mediating role between psychosocial factors and physical activity. Furthermore, daily sleep efficiency and number of awakenings were predictors for daily sedentary time. Overall, the results indicated that psychosocial factors and sleep disturbances should be assessed because of their impact on physical activity after cardiac surgery. In addition, patients’ daily sleep disturbances after cardiac surgery should be assessed because they can predict their next-day physical activity.