title: Can exercise limits prevent post-exertional malaise in chronic fatigue syndrome? An uncontrolled clinical trial.
abstract: 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.
  
  
  METHODS
  An uncontrolled clinical trial (semi-experimental design).
  
  
  METHODS
  Outpatient clinic of a university department.
  
  
  METHODS
  Twenty-four patients with chronic fatigue syndrome.
  
  
  METHODS
  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.
  
  
  METHODS
  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 > or =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 > or =20). There was no change in activity limitations/participation restrictions.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Human Physiology, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Belgium. j.nijs@ha.be
authors.forename: Jo
authors.initials: J
authors.lastname: Nijs
authors.forename: Freya
authors.initials: F
authors.lastname: Almond
authors.forename: Pascale
authors.initials: P
authors.lastname: De Becker
authors.forename: Steven
authors.initials: S
authors.lastname: Truijen
authors.forename: Lorna
authors.initials: L
authors.lastname: Paul
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005080:Exercise Test; D005081:Exercise Therapy / Q000009:adverse effects / Q000379:methods*; D017079:Exercise Tolerance; D015673:Fatigue Syndrome, Chronic / Q000534:rehabilitation / Q000628:therapy*; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D011788:Quality of Life; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D016138:Walking