I went to the gym today. I didn’t want to. I’m tired and my arm that has been a saga of five surgeries and three and a half years was giving me some definite grief, not to mention the pain of some of my other injuries, both recent and chronic. But I went with the idea that I just wanted/needed to do something. I started small, going through the motions of my typical warm up, and before I knew it I was putting in a fairly intense workout. I forgot that I was tired and when my body got moving some of my injuries seemed to quiet down. I’m now post workout and feeling significantly better than I did for the first half of my day. Which of course made me wonder, is there any research on the effects of exercise on pain?
Whiteside, Hansen, and Chaudhuri (2004) compared a small number of individuals diagnosed with chronic fatigue syndrome with age and sex matched controls. Both groups participated in an exercise program and then had their pain thresholds measured. The controls had increased pain thresholds after exercise while the individuals with chronic fatigue syndrome saw their thresholds decrease. Note: chronic fatigue syndrome is a condition that does not have a known cause. Individuals with this syndrome suffer extreme fatigue which can be worsened by physical or mental activity; however, rest does not improve the level of fatigue. (I wonder if this is why the first thing my physio treats always seems to be the worst?)
Nijs, Kosek, Van Oosterwijck, and Meeus (2012) found that the increased pain threshold found following exercise is due to activation of an internal system that helps to reduce pain (endogenous analgesia). Our bodies respond to exercise by inhibiting our nociception (pain sensing), and releasing endorphins that activate opioid receptors. In comparing different groups they found that certain groups such as fibromyalgia patients do not activate this internal system in the same way or at all. In addition, they found that exercising painful muscles does not change pain sensitivity but exercising non-painful muscles does. In other words, if you have an acute injury you won’t be able to decrease the pain you feel by exercising that part of your body, but you may be able to decrease it by exercising other parts of you. (I tried this out after one of my wrist surgeries by propping my arm up safely and getting on my spin bike – it helped a lot).
Geneen, Moore, Clarke, Martin, Colvin, and Smith (2017) conducted a review of reviews of research from the Cochrane Database of Systematic Reviews. They examined studies of the impact of physical activity and exercise by chronic pain sufferers on their pain severity, physical function, psychological function (avoiding other conditions like depression), and quality of life. They indicate that the results were generally positive, with exercise having small to moderate positive effects on the issues examined but also describe that most of the studies are small and did not follow-up with subjects for extended periods. So yes, there is potential for exercise and chronic pain management but we need to do more research to really understand the relationship. I have definitely tried this out as well and can say that for me, exercise has a huge effect on my physical function, psychological function, and quality of life.
The thing about pain is that there is actually a whole heck of a lot that we don’t really understand. It wasn’t that long ago that the recommended treatment to any sort of injury was complete rest. The few studies I have included here all indicate why, in most cases that isn’t the way to go. And my own experience speaks volumes.
Geneen LJ, Moore RA, Clarke C, Martin D, Colvin LA, & Smith BH. (2017). Physical activity and exercise for chronic pain in adults: an overview of Cochrane Reviews. Cochrane Database of Systematic Reviews, Issue 4. Art. No.: CD011279. DOI: 10.1002/14651858.CD011279.pub3.
Nijs, Jo, Kosek, E., Van Oosterwijck, J., & Meeus, M. (2012). Dysfunctional endogenous analgesia during exercise in patients with chronic pain : to exercise or not to exercise? PAIN PHYSICIAN, 15(3S), ES205–ES213.
Whiteside, A., Hansen, S., & Chaudhuri, A. (2004). Exercise lowers pain threshold in chronic fatigue syndrome. Pain, 109(3), 497-499. https://doi.org/10.1016/j.pain.2004.02.029