Physical activity and endogenous pain modulation in older people: a scoping review

Introduction: Pain is a common issue in older adults and significantly impacts their quality of life. While physical activity (PA) is widely recommended as a non-pharmacological strategy, the mechanisms underlying its analgesic effects remain incompletely understood. One possible mechanism behind positive effects of PA on pain may be its influence on endogenous pain modulation (EPM). This scoping review aimed to provide a systematic overview of the literature on PA and EPM, assessed using conditioned pain modulation (CPM), with a focus on older adults experiencing pain. The review mapped: (i) types of PA used to study EPM in older people; (ii) intervention protocols assessing PA and EPM via CPM in older adults with pain; and (iii) gaps requiring further research or adaptations tailored to this population. Methods: This review was conducted following the JBI methodology for scoping reviews. Multiple databases were searched: MEDLINE (Ovid), CINAHL (EBSCOhost), Embase, Cochrane Library, Web of Science, JBI Evidence Synthesis, PsycINFO, and PEDro. There was no restriction on language or geography. Studies were included if they examined people aged 60 or older, used PA to assess its effect on pain modulation, and used CPM as an outcome measure. Studies that did not use this outcome or included younger populations without subgroup analysis were excluded. Studies from 2000 onwards were considered. The results were organized narratively and presented with tables and figures. Results: The search yielded 1852 records. Six studies met the inclusion criteria. The included studies used various PA interventions, including strength-based and aerobic exercises, to assess their effects on pain sensitivity and modulation. While all studies used CPM as an outcome measure, they applied diverse testing paradigms to evaluate EPM. Although all studies reported a general hypoalgesic effect of PA in older adults, only some showed measurable improvement in EPM. Conclusion The variability in methodologies across studies underscores the need to standardize pain modulation protocols before applying them more broadly to older adults, a population with added complexities and age-related factors challenging result interpretation. Future research should aim to refi ne PA recommendations by tailoring interventions to enhance both clinical outcomes and adherence in this population.