Exercise-induced pain threshold modulation in healthy subjects: a systematic review and meta-analysis

Area of Science:

• Exercise science
• Pain research
• Human physiology

Background:

• Exercise is a potential non-pharmacological intervention for pain modulation.
• Exercise-induced hypoalgesia refers to the reduction in pain sensitivity following physical activity.
• Pain threshold (PT) is a key indicator of pain sensitivity and can be used to assess exercise effects.

Purpose of the Study:

• To systematically review and meta-analyze the impact of exercise on pain threshold in healthy populations.
• To quantify the overall effect of exercise on PT and identify factors influencing this response.

Main Methods:

• A comprehensive literature search was conducted across major databases (MEDLINE, EMBASE, Web of Science, Lilacs, Scopus) for studies published up to December 2019.
• Inclusion criteria comprised randomized controlled trials and quasi-experimental studies involving healthy subjects, exercise interventions, and PT assessments.
• Hedge's effect sizes and random-effects meta-analyses were employed to calculate the PT response.

Main Results:

• Thirty-six studies with 1326 participants were included in the final analysis.
• A significant and homogenous increase in PT was observed in healthy subjects (ES=0.19, 95% CI=0.11 to 0.27).
• Subgroup analyses revealed greater PT increases in women (ES=0.36), with strength exercise (ES=0.34), and moderate intensity exercise (ES=0.27).

Conclusions:

• Exercise demonstrates small to moderate effects on increasing PT in healthy individuals.
• Moderate-intensity strength exercise and participation by women yield higher PT responses.
• Findings support exercise's role in modulating endogenous pain systems and suggest clinical applications for chronic pain management.