Pain inhibition and postexertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome: An experimental study

Authors

  • J. Van Oosterwijck,

    1. From the  Department of Human Physiology, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels
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  • J. Nijs,

    1. From the  Department of Human Physiology, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels
    2.  Division of Musculoskeletal Physiotherapy, Department of Health Care Sciences, Artesis University College Antwerp, Antwerp
    3.  Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels
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  • M. Meeus,

    1. From the  Department of Human Physiology, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels
    2.  Division of Musculoskeletal Physiotherapy, Department of Health Care Sciences, Artesis University College Antwerp, Antwerp
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  • I. Lefever,

    1. From the  Department of Human Physiology, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels
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  • L. Huybrechts,

    1.  Division of Musculoskeletal Physiotherapy, Department of Health Care Sciences, Artesis University College Antwerp, Antwerp
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  • L. Lambrecht,

    1.  Private Practice For Internal Medicine, Ghent/Aalst
    2.  CVS Contactgroep, Bruges, Belgium
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  • L. Paul

    1.  Nursing and Health Care, Faculty of Medicine, University of Glasgow, Glasgow, UK
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J. Nijs, Vrije Universiteit Brussel, Department of Human Physiology, Faculty of Physical Education & Physiotherapy, Building L – 3rd floor, Pleinlaan 2, BE-1050 Brussels, Belgium.
(fax: +32 2 629 28 76; e-mail: Jo.Nijs@vub.ac.be).

Abstract

Abstract.  Van Oosterwijck J, Nijs J, Meeus M, Lefever I, Huybrechts L, Lambrecht L, Paul L (Vrije Universiteit Brussel, Brussels; Artesis University College Antwerp, Antwerp; University Hospital Brussels, Brussels; Private Practice For Internal Medicine, Ghent/Aalst; CVS Contactgroep, Bruges; Belgium; and University of Glasgow, Glasgow, UK). Pain inhibition and postexertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome. J Intern Med 2010; 268: 265–278.

Objectives.  To examine the efficacy of the pain inhibitory systems in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) during two different types of exercise and to examine whether the (mal)functioning of pain inhibitory systems is associated with symptom increases following exercise.

Design.  A controlled experimental study.

Setting and subjects.  Twenty-two women with ME/CFS and 22 healthy sedentary controls were studied at the Department of Human Physiology, Vrije Universiteit Brussel.

Interventions.  All subjects performed a submaximal exercise test and a self-paced, physiologically limited exercise test on a cycle ergometer. The exercise tests were undertaken with continuous cardiorespiratory monitoring. Before and after the exercise bouts, subjects filled out questionnaires to assess health status, and underwent pressure pain threshold measurements. Throughout the study, subjects’ activity levels were assessed using accelerometry.

Results.  In patients with ME/CFS, pain thresholds decreased following both types of exercise, whereas they increased in healthy subjects. This was accompanied by a worsening of the ME/CFS symptom complex post-exercise. Decreased pressure thresholds during submaximal exercise were associated with postexertional fatigue in the ME/CFS group (r = 0.454; = 0.034).

Conclusions.  These observations indicate the presence of abnormal central pain processing during exercise in patients with ME/CFS and demonstrate that both submaximal exercise and self-paced, physiologically limited exercise trigger postexertional malaise in these patients. Further study is required to identify specific modes and intensity of exercise that can be performed in people with ME/CFS without exacerbating symptoms.

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