Physical activity behavior predicts endogenous pain modulation in older adults

Abstract

Older adults compared with younger adults are characterized by greater endogenous pain facilitation and a reduced capacity to endogenously inhibit pain, potentially placing them at a greater risk for chronic pain. Previous research suggests that higher levels of self-reported physical activity are associated with more effective pain inhibition and less pain facilitation on quantitative sensory tests in healthy adults. However, no studies have directly tested the relationship between physical activity behavior and pain modulatory function in older adults. This study examined whether objective measures of physical activity behavior cross-sectionally predicted pain inhibitory function on the conditioned pain modulation (CPM) test and pain facilitation on the temporal summation (TS) test in healthy older adults. Fifty-one older adults wore an accelerometer on the hip for 7 days and completed the CPM and TS tests. Measures of sedentary time, light physical activity (LPA), and moderate to vigorous physical activity (MVPA) were obtained from the accelerometer. Hierarchical linear regressions were conducted to determine the relationship of TS and CPM with levels of physical activity, while controlling for demographic, psychological, and test variables. The results indicated that sedentary time and LPA significantly predicted pain inhibitory function on the CPM test, with less sedentary time and greater LPA per day associated with greater pain inhibitory capacity. Additionally, MVPA predicted pain facilitation on the TS test, with greater MVPA associated with less TS of pain. These results suggest that different types of physical activity behavior may differentially impact pain inhibitory and facilitatory processes in older adults.

Duration of symptoms is associated with conditioned pain modulation and somatosensory measures in knee osteoarthritis

“…Enhanced CPM has been associated with participation in exercise, thus individuals with CPM impairment in this study may have lived a more sedentary lifestyle than those with intact CPM. Regular physical activity has been demonstrated to prevent development of chronic muscle pain .…”

How does physical activity modulate pain?

“…These two types of psychophysical measures can be assessed using a variety of noxious stimuli and at different anatomical locations that can alter the response, suggesting these centrally-mediated pain processing pathways may not be universal indicators as once thought. For example, the responses to deep tissue pressure or heat, two commonly used test stimuli, can show disparate responses as observed here by Naugle et al[12]. Similarly, pain sensitivity is not uniform across modalities, where some individuals are more sensitive to noxious heat, others to ischemia, others to heat temporal summation [7].…”

“…On the other hand, a sedentary lifestyle enhances the risk for development of chronic pain [10], and those with chronic pain have lower levels of physical activity than healthy controls [4]. Further, as pointed out by Naugle et al, in this issue of PAIN [12], older adults have a higher incidence of chronic pain and are generally less physically active than younger adults. Despite the increasing body of evidence supporting the relationship between greater physical activity and pain reduction, the underlying mechanisms of how physical activity prevents pain and how exercise reduces chronic pain are only beginning to be unraveled.…”

“…The study by Naugle et al in the current issue of PAIN [12], examined the relationship between physical activity and pain on central pain processing in pain-free (healthy) older adults. The current study showed that greater temporal summation to heat was associated with lower moderate to vigorous physical activity levels; while greater sedentary behavior and lower levels of light physical activity were associated with less conditioned pain modulation (CPM) to heat, but not to pressure following a cold water conditioning stimulus.…”

Effects of repeated conditioning pain modulation in healthy volunteers

“…Pain thresholds are the most common outcome for CPM‐effects (Nir et al., ; Razavi et al., ; Zheng et al., ; Coppieters et al., ; Flood et al., , ; Naugle et al., ; Smith and Pedler, ) and both PDT and PTT can reliably assess CPM‐effects by means of the computerized pressure cuff (Graven‐Nielsen et al., ), albeit that within‐session reliability of PDT is higher compared to PTT (Imai et al., ). In this study, the CPM‐effects of the conditioning stimulus were analysed by the PDT (for PTT effects see Appendix ) from the test‐stimuli (Graven‐Nielsen et al., ).…”