Can exercise limits prevent post-exertional malaise in chronic 
fatigue syndrome? An uncontrolled clinical trial.

Clin Rehabil. 2008 May;22(5):426-35.

Nijs J, Almond F, De Becker P, Truijen S, Paul L.

Department of Human Physiology, Faculty of Physical 
Education and Physiotherapy, Vrije Universiteit Brussel. j.nijs@ha.be.

NLM Citation: PMID: 18441039


Objective: It was hypothesized that the use of exercise limits 
prevents symptom increases and worsening of their health status 
following a walking exercise in people with chronic fatigue syndrome.

Design: An uncontrolled clinical trial (semi-experimental design).

Setting: Outpatient clinic of a university department.

Subjects: Twenty-four patients with chronic fatigue syndrome.

Interventions: Subjects undertook a walking test with the two 
concurrent exercise limits. Each subject walked at an intensity where 
the maximum heart rate was determined by heart rate corresponding to 
the respiratory exchange ratio = 1.0 derived from a previous 
submaximal exercise test and for a duration calculated from how long 
each patient felt they were able to walk.

Main outcome measures: The Short Form 36 Health Survey or SF-36, the 
Chronic Fatigue Syndrome Symptom List, and the Chronic Fatigue 
Syndrome - Activities and Participation Questionnaire were filled in 
prior to, immediately after and 24 hours after exercise.

Results: The fatigue increase observed immediately post-exercise (P= 
0.006) returned to pre-exercise levels 24 hours post-exercise. The 
increase in pain observed immediately post-exercise was retained at 
24 hours post-exercise (P=0.03). Fourteen of the 24 subjects 
experienced a clinically meaningful change in bodily pain (change of 
SF-36 bodily pain score >/=10); 6 indicated that the exercise bout 
had slightly worsened their health status, and 2 had a clinically 
meaningful decrease in vitality (change of SF-36 vitality 
score >/=20). There was no change in activity 
limitations/participation restrictions.

Conclusion: It was shown that the use of exercise limits (limiting 
both the intensity and duration of exercise) prevents important 
health status changes following a walking exercise in people with 
chronic fatigue syndrome, but was unable to prevent short-term 
symptom increases.