People with chronic pain think of improved sleep as one of the most important outcomes of treatment. Physical activity has been shown to have beneficial effects on sleep in the general population. Despite this, the physical activity-sleep relationship has not been directly examined in a chronic pain sample. This study had the goal of examining the association between objective daytime physical activity and subsequent objective sleep for individuals with chronic pain while controlling for pain and psychosocial variables. An observational prospective within-persons study design was employed. A clinical sample of fifty adults with chronic pain was recruited. Participation involved completing a demographic questionnaire followed by five days of data collection. During this period participants wore a tri-axial accelerometer to monitor their daytime activity and sleep. Participants also carried a Palm Hand Held Computer that administered a questionnaire measuring pain, mood, catastrophizing, and stress, six times over the course of the day. Results showed that higher fluctuations in daytime activity significantly predicted shorter sleep duration. Furthermore, higher mean daytime activity levels and a larger number of pain sites contributed significantly to the prediction of longer periods of wakefulness at night. The small sample size used in this study limits the generalizability of findings. Missing data may have led to over- or under-estimations of effect sizes, and additional factors that may be related to sleep (such as medication usage and environmental factors) were not measured.
Results of this study indicate engagement in high intensity activity and high fluctuations in activity are related to poorer sleep at night; therefore, activity modulation may be a key treatment strategy to deal with sleep complaints in individuals with chronic pain.