Another Belgian exercise study
Pain inhibition and post-exertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome
Jessica Van Oosterwijck a , Jo Nijs a,b,c , Mira Meeus a,b , Inne Lefever a , Lynn Huybrechts b , Luc Lambrecht d and Lorna Paul e
a Department of Human Physiology, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium
b Division of Musculoskeletal Physiotherapy, Department of Health Care Sciences, Artesis University College Antwerp, Antwerp, Belgium
c Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels, Belgium
d Private practice for internal medicine, Ghent / Aalst, Belgium & CVS Contactgroep, Bruges, Belgium
e Nursing and Health Care, Faculty of Medicine, University of Glasgow, Glasgow, United Kingdom
Copyright C 2010 Blackwell Publishing Ltd
KEYWORDS pain . post-exertional malaise . submaximal exercise . algometry . ME/CFS
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 post-exertional fatigue in the ME/CFS group (r=.454; p=.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 post-exertional 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.