Physical Activity And Exercise As Therapies For Chronic Pain

Here is a review of studies of the effect of physical activity/exercise on chronic pain. The conclusion of the abstract:
 

AUTHORS' CONCLUSIONS: The quality of the evidence examining physical activity and exercise for chronic pain is low. This is largely due to small sample sizes and potentially underpowered studies. A number of studies had adequately long interventions, but planned follow-up was limited to less than one year in all but six reviews. There were some favourable effects in reduction in pain severity and improved physical function, though these were mostly of small-to-moderate effect, and were not consistent across the reviews. There were variable effects for psychological function and quality of life. The available evidence suggests physical activity and exercise is an intervention with few adverse events that may improve pain severity and physical function, and consequent quality of life. However, further research is required and should focus on increasing participant numbers, including participants with a broader spectrum of pain severity, and lengthening both the intervention itself, and the follow-up period.

The bottom line is that there is some evidence for improvement of pain severity and quality of life, but the studies had some flaws (e.g., small sample sizes) and so some of the effects were small and/or inconsistent. Further better and larger studies are required to ascertain the extent to which physical activity can alleviate chronic pain.