What Effect Can Sleep Have on Physical Activity, Later Pain Onset?

Low levels of sleep disturbance were associated with reduced likelihood of later pain after physical activity in a US population cohort aged 50 and older, according to study findings published in BMJ Open.

The significance of sleep disturbance has been found in the past to exacerbate issues of pain in patients with conditions such as Parkinson disease and rheumatoid arthritis. This may be explained by identified associations in prior studies that link sleep problems with increased levels of inflammatory markers. Notably, the anti-inflammatory impact of physical activity also represents a vital intervention in patients with these conditions.

Researchers highlighted the positive correlation between sleep and physical activity, with higher levels of physical activity associated with improvements in subjectively and objectively measured sleep. However, the impact of pain, which affects 20% of the global adult population, has been noted as a potential issue to adherence of physical activity.

The study authors sought to examine whether sleep disturbance modifies the link between physical activity and incident pain, conducting a prospective population-based study on US adults aged 50 and older (n = 8036) who completed follow-up data for adjusted analyses (weighted analysis population, n = 42,407,222).

Physical activity was assessed via interview with questions on time spent in moderate and vigorous physical activity, with sleep disturbance assessed using a modified form of the Jenkins Sleep Scale. Participants reported no troublesome pain at baseline (2014) and were reassessed for pain in 2016, with sleep being considered as a potential moderator between pain and physical activity.

Study authors indicated that 37.9% of the 2014 baseline pain-free sample in the weighted analysis participated in moderate or vigorous physical activity once a week or less, with an overall mean Physical Activity Index Score of 9.0 (SE = 0.12).

After conducting the weighted analyses, researchers found that for each point higher on the Physical Activity Index Score, reduced odds ratio (OR) of incident pain was exhibited for those who reported sleep disturbance never/rarely (OR = 0.97; 95% CI, 0.94—0.99). These associations were not found for participants who reported sleep disturbance sometimes (OR = 0.99; 95% CI, 0.97–1.01) or most of the time (OR = 1.01; 95% CI, 0.99–1.03). Moreover, the analysis of possible interaction showed that frequency of sleep disturbance moderated the physical activity and incident pain association (Wald test: P = .02).

Researchers note that study findings warrant further investigation. “Replication would provide a strong case for integrating sleep health alongside physical activity recommendations for older adults to promote healthy ageing and prevention of pain onset,” concluded the study authors.

Reference

Whibley D, Guyer HM, Swanson LM, et al. Sleep disturbance as a moderator of the association between physical activity and later pain onset among American adults aged 50 and over: evidence from the Health and Retirement Study. BMJ Open. 2020;10:e036219.