Since returning home, some 100,000 veterans from the first Gulf War have reported chronic musculoskeletal pain (CMP) similar to fibromyalgia, and a new study in The Journal of Pain, published by the American Pain Society, shows that acute exercise can exacerbate the pain, but that long-term exercise has the opposite outcome and reduces it.
Researchers from Middleton Memorial Hospital in Madison, Wis. and the University of Wisconsin tested levels of experimental pain sensitivity in Gulf War veterans following acute exercise sessions. They hypothesized that veterans with CMP would report lower pain thresholds and higher pain intensity from experimental pain stimuli than healthy Gulf War veterans. Vets with CMP also were predicted to rate naturally occurring pain from exercise as more intense. Thirty-two veterans (15 with CMP and 17 healthy) were studied, and the study protocols were reviewed and approved by the VA.
The researchers reported that, consistent with their hypothesis, vets with CMP claimed that heat-induced pain stimuli was more intense and unpleasant than evidenced in healthy subjects. They also had greater leg pain intensity during exercise and were more sensitive to the pain stimuli following acute exercise compared to pre-exercise ratings. Pain thresholds, however, did not show significant differences between healthy subjects and those with CMP, contrary to what the researchers hypothesized.
The authors noted that exercise research in chronic muscle pain patients shows a paradox in that acute exercise appears to exacerbate pain while chronic exercise can reduce pain.
So the challenge for clinicians is to encourage regular exercise for CMP patients to avoid disability, even though initial exercise regimens may increase pain in the short run. With fibromyalgia patients, studies show that regular exercise is one of the few consistently efficacious treatments and is critical for avoiding long-term disability and mood disorders. The authors concluded that their results show acute exercise influences the suffering components of pain and can be helpful to clinicians in prescribing appropriate physical activity for patients with CMP.
