Promoting physical activity is key to the management of chronic pain, but little is understood about the factors facilitating an individual’s engagement in physical activity on a day-to-day basis.
In this new study Dr. Nicole Tang, author of study and co-author Dr. Adam Sanborn from the University of Warwick's Department of Psychology, examined the within-person effect of sleep on next day physical activity in patients with chronic pain and insomnia.
For the study 119 participants were patients recruited consecutively from a hospital pain clinic in London, United Kingdom. Participants were working adults aged 18 to 65 years, non-malignant pain of at least 6 months; scoring 15 or higher on the Insomnia Severity Index (chronic insomnia).
The majority of the participants had more than one pain location (87%). Lower back (73%) was the commonest site of pain, followed by legs (54%), neck (38%), shoulders (33%), knees (35%), arms (21%), upper back (22%) and joints (22%).
Patients monitored their sleep and physical activity for a week in their usual sleeping and living environment. Physical activity was measured using actigraphy to provide a mean activity score each hour. Sleep was estimated with actigraphy and an electronic diary, providing an objective and subjective index of sleep efficiency and a sleep quality rating.
Researchers used the time-specific data to determine, for individual patients, whether the quality of their sleep had an impact on how physically active they were the following day. Multilevel models for each of the predictors were fit, and the only reliable predictor of physical activity was sleep quality.
The results showed sleep quality was was the only significant within-person predictor of subsequent physical activity, such that nights of higher sleep quality were followed by days of more physical activity, from noon to 11pm. Sleep was a better predictor of physical activity than morning ratings of pain intensity or mood.
The researchers write "In the absence of interventions, chronic pain patients spontaneously engaged in more physical activity following a better night of sleep. Improving nighttime sleep may well be a novel avenue for promoting daytime physical activity in patients with chronic pain.”
Dr. Tang commented that "the prospect of promoting physical activity by regulating sleep may offer a novel solution to an old problem".
"The current study identified sleep quality, rather than pain and low mood, as a key driver of physical activity the next day. The finding challenges the conventional target of treatment being primarily focused on changing what patients do during the day. Sleep has a naturally recuperative power that is often overlooked in pain management. A greater treatment emphasis on sleep may help patients improve their daytime functioning and hence their quality of life" argued Dr. Tang.
This study is published in PLoS One.