Unravelling the nature of postexertional malaise in myalgic
encephalomyelitis/chronic fatigue syndrome: the role of elastase, complement
C4a and interleukin-1beta.**
Nijs J, Van Oosterwijck J, Meeus M, Lambrecht L, Metzger K, Frémont M, Paul
Department of Human Physiology, Faculty of Physical Education &
Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium.
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)-1beta and complement C4a levels.
DESIGN: Comparative experimental design.
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-1beta or complement C4a
split product levels in people with ME/CFS or healthy sedentary control
subjects (P > 0.05). Postexercise complement C4a level was identified as a
clinically important biomarker for postexertional malaise in people with
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-1beta,
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.
I learned very early the difference between knowing the name of something
and knowing something.
Richard Feynman The Physics Teacher Vol. 7, issue 6 (1969)