Exercise-Induced Hypoalgesia in Healthy Individuals and People With Chronic Musculoskeletal Pain: A Systematic Review and Meta-Analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 32599154 · doi:10.1016/j.jpain.2020.04.003
What was done
Authors systematically reviewed randomized controlled trials published from 1980 to January 2020 evaluating experimentally induced pain before and during or after a single bout of exercise in healthy individuals or people with chronic musculoskeletal pain. Study quality was evaluated using the Cochrane Risk of Bias tool and GRADE, and outcomes were synthesized using random-effects meta-analyses across 13 included studies identified from 5,829 screened records.
What was found
In healthy individuals, aerobic exercise produced a large hypoalgesic effect (7 studies, n = 236; g = -0.85 [-1.58, -0.13]) and dynamic resistance exercise produced a small hypoalgesic effect (2 studies, n = 23; g = -0.45 [-0.69, -0.22]), whereas isometric exercise did not cause significant hypoalgesia (3 studies, n = 177; g = -0.16 [-0.36, 0.05]). In chronic musculoskeletal pain, isometric exercise showed no significant effect (3 studies, n = 114; g = -0.41 [-1.08, 0.25]); aerobic exercise (0 studies) and dynamic resistance exercise (1 study) could not be meta-analyzed.
Why it matters
This review confirms that acute aerobic and dynamic resistance exercise reduce experimental pain sensitivity in healthy individuals. However, it demonstrates a substantial evidence gap for clinical populations, showing that exercise-induced hypoalgesia cannot yet be assumed in patients with chronic musculoskeletal pain.
Limits
The findings are limited by small overall sample sizes across trials (e.g., n = 23 for dynamic resistance in healthy participants) and an unclear risk of bias in the included studies. The review evaluated experimental rather than clinical pain, and there were no eligible studies examining aerobic exercise in chronic pain cohorts.
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