Chronic pain is defined as persistent pain beyond normal tissue healing time. Chronic pain syndromes have a considerable impact on functional capacity, resulting in disrupted work and social activities; therefore, the impact of these syndromes affect the society at large and at a high economic cost. In contrast to rest and pharmacological treatment, multidisciplinary programs with exercises have shown to improve pain and function in chronic pain patients. A number of studies reported analgesia induced by exercise; however, the neurological mechanisms involved are not known yet. To explore this phenomenon, we describe endogenous pain control relating some studies on general population and chronic pain subjects, and we conclude this paper with some clinical consideration to determine optimal intensity of exercise to produce hypoalgesia.
chronic pain; exercise; endogenous pain control systems
