EXERCISE-INDUCED HYPOALGESIA / MULTISYSTEM PAIN MODULATION

EXERCISE-INDUCED HYPOALGESIA

Exercise-induced hypoalgesia (EIH) is a temporary reduction in pain sensitivity during or after some forms of exercise. It is not universal. Effects vary with exercise type, intensity, duration, body region, training status, individual characteristics, and pain condition.

The 2026 narrative review, Exercise-Induced Hypoalgesia: Cellular and Molecular Mechanisms Linking Pain Modulation and Stress Regulation (PMID 42193869), presents EIH as a multisystem phenomenon potentially involving PAG, RVM, spinal modulation, endogenous opioids, endocannabinoids, serotonergic and noradrenergic systems, autonomic regulation, HPA axis, immune signalling, and myokines.

Evidence is uneven: some mechanisms have stronger human evidence; others rely substantially on animal or translational research.

Reject: exercise → endorphins → pain disappears.

Use instead: exercise → multisystem stress + pain modulation.

Removal audit: without EIH, the Brain loses the distinction between temporary exercise-related modulation and the mythology of universal analgesia.