Unravelling the nature of postexertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome: the role of elastase, complement C4a and interleukin-1 beta

J. Nijs, J. Van Oosterwijck, M. Meeus, L. Lambrecht, K. Metzger, M. Fremont, L. Paul

    Research output: Contribution to journalArticle


    Objectives. Too vigorous exercise or activity increase frequently triggers postexertional malaise in people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), a primary characteristic evident in up to 95% of people with ME/CFS. The present study aimed at examining whether two different types of exercise results in changes in health status, circulating elastase activity, interleukin (IL)-1 beta and complement C4a levels.
    Design. Comparative experimental design.
    Setting. University.
    Subjects. Twenty-two women with ME/CFS and 22 healthy sedentary controls Interventions: participants were subjected to a submaximal exercise (day 8) and a self-paced, physiologically limited exercise (day 16). Each bout of exercise was preceded and followed by blood sampling, actigraphy and assessment of their health status.
    Results. Both submaximal exercise and self-paced, physiologically limited exercise resulted in postexertional malaise in people with ME/CFS. However, neither exercise bout altered elastase activity, IL-1 beta or complement C4a split product levels in people with ME/CFS or healthy sedentary control subjects (P gt; 0.05). Postexercise complement C4a level was identified as a clinically important biomarker for postexertional malaise in people with ME/CFS.
    Conclusions. Submaximal exercise as well as self-paced, physiologically limited exercise triggers postexertional malaise in people with ME/CFS, but neither types of exercise alter acute circulating levels of IL-1 beta, complement C4a split product or elastase activity. Further studying of immune alterations in relation to postexertional malaise in people with ME/CFS using multiple measurement points postexercise is required
    Original languageEnglish
    Pages (from-to)418-435
    Number of pages18
    JournalJournal of Internal Medicine
    Issue number4
    Publication statusPublished - Apr 2010



    • allergy
    • women
    • blood care
    • chronic fatigue syndrome
    • exercise
    • fibromyalgia
    • graded-exercise
    • health
    • human
    • immune dysfunction
    • immunity
    • in-vivo
    • increased intervention level
    • measurement oxidative stress
    • pain
    • people performance
    • postexertional malaise

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