Publications
The Journal of Pain • Volume 11, No. 8, August 2010
Exercise Alters Pain Sensitivity in Gulf War Veterans with Chronic Musculoskeletal Pain
Dane B. Cook, Aaron J. Stegner and Laura D. Ellingson, Middleton Memorial Veterans Hospital and the University of Wisconsin
Since returning home, almost 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 shows that acute exercise exacerbates the pain but long-term exercise has the opposite outcome and reduces it.
Researchers from Middleton Memorial Hospital in Madison, WI. 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.
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, therefore, 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.
The Relationship of Changes in Pain Quality to Pain Interference and Sleep Quality
Mark P. Jensen, Errol M. Gould, Timothy W. Victor, Arnold R. Gammaitoni, Richard E. White and Bradley S. Galer, University of Washington and collaborating commercial organizations
For carpal tunnel syndrome sufferers, itching and throbbing are pain qualities most responsible for impaired functioning and sleep disruption, according to new research reported in The Journal of Pain.
Researchers from the University of Washington examined how pain-quality measures, not pain intensity, are associated with how pain interferes with normal function. No previous study had examined the associations between pain quality (sharp, sensitive, deep, surface, etc.) and changes in patient functioning and quality of life. The researchers hypothesized that ratings of pain quality would show significant independent associations with function interference and sleep disruption. They anticipated that deep pain would be a pain quality with strong associations to impaired functioning.
Subjects for the study were participants in a clinical trial comparing lidocaine patch 5% to naproxen 500 mg. in 100 patients with carpel tunnel syndrome. All participants were given the Brief Pain Inventory questionnaire and sleep quality was assessed using a five point rating scale.
Results showed, for the first time, that measures of specific pain qualities were associated with changes in patient functioning over and above pain intensity and other global pain measures. Among the carpel tunnel patients, itch and throbbing were the pain qualities most highly associated with impaired function and sleep disruption. This finding, according to the authors, underscores the significance of assessing pain quality as a major variable for thorough pain assessments.
For the carpel tunnel patients, throbbing was a unique individual predictor for pain interference and itching had the most significant impact on sleep quality.
“Pain is much more than just intensity and unpleasantness,” said lead author Mark P. Jensen, PhD. “Knowledge of pain quality, as well as pain intensity, provides additional clues for understanding the impact of pain on patient’s life.”
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