Exercise-induced pain threshold modulation in healthy subjects: a systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of 36 randomized controlled trials and quasi-experimental studies.
PubMed 33409362 · doi:10.21801/ppcrj.2020.63.2
What was done
Researchers systematically searched MEDLINE, EMBASE, Web of Science, Lilacs, and Scopus through December 2019 for randomized controlled trials and quasi-experimental studies evaluating the effect of exercise interventions on pain threshold (PT) in healthy participants. Data from 36 studies involving 1,326 subjects were pooled using random-effects meta-analysis to calculate Hedges' effect sizes (ES) and 95% confidence intervals, alongside subgroup and meta-regression analyses examining sex, exercise type, intensity, and age.
What was found
Exercise led to a statistically significant, homogeneous increase in pain threshold overall (ES = 0.19, 95% CI: 0.11 to 0.27, I² = 7.5%). Subgroup analyses demonstrated larger effect sizes in studies consisting of women (ES = 0.36), strength exercise protocols (ES = 0.34), and moderate-intensity exercise (ES = 0.27). Age did not show a significant moderating effect.
Why it matters
This review quantifies the acute hypoalgesic effect of exercise in healthy populations, indicating that moderate-intensity resistance training produces stronger pain-dampening responses than other exercise modalities.
Limits
The analysis is restricted entirely to healthy individuals, limiting direct generalization to clinical chronic pain populations where endogenous pain modulation is often impaired. The review combined randomized controlled trials with quasi-experimental designs without reporting separate effect estimates by design quality, and the abstract does not report specific pain modalities tested (e.g., pressure, thermal, electrical) or the duration of post-exercise pain threshold changes.
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- supports Sub-threshold exercise progression increases the baseline pain threshold through the physiological principle of pain desensitization.