title: Deviations in daily physical activity patterns in patients with the chronic fatigue syndrome: a case control study.
abstract: OBJECTIVE
  Deviations in daily physical activity patterns may play an important role in the development and maintenance of fatigue in the chronic fatigue syndrome (CFS). The aim of this study is to gain insight into the objective daily physical activity pattern of patients with CFS in comparison with healthy controls. The secondary objective is studying the awareness in performing physical activities.
  
  
  METHODS
  The objective daily physical activity pattern was measured with a tri-axial accelerometer in 35 patients with CFS and in 35 age- and gender-matched healthy controls. The objective daily physical activity level and distribution of physical activities at low, medium and high intensity levels during the day were measured. Moreover, variability in performing physical activities within and between subjects was computed. Subjective ratings of self-reported daily physical activity levels were assessed at a visual analog scale.
  
  
  RESULTS
  CFS patients were significantly less physically active in the afternoon and evening, and spent fewer activities at high intensity levels and more at low intensity levels. Moreover, CFS patients showed more variability in their own physical activity pattern during the afternoon. The heterogeneity in the physical activity pattern between subjects within the CFS and control group did not differ. Finally, CFS patients were more aware about their daily physical activity level than healthy controls.
  
  
  CONCLUSIONS
  CFS patients showed deviations in the objectively measured daily physical activity pattern. Future research should elucidate the relation between impaired balances in daily physical activity patterns and fatigue severity in CFS.
authors.affiliation: Roessingh Research and Development, Post Box 310, 7500 AH Enschede, The Netherlands. r.evering@rrd.nl
authors.forename: Richard M H
authors.initials: RM
authors.lastname: Evering
authors.forename: Thijs M
authors.initials: TM
authors.lastname: Tönis
authors.forename: Miriam M R
authors.initials: MM
authors.lastname: Vollenbroek-Hutten
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology*; D000328:Adult; D016022:Case-Control Studies; D003071:Cognition; D003430:Cross-Sectional Studies; D015673:Fatigue Syndrome, Chronic / Q000523:psychology* / Q000534:rehabilitation*; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity; D010147:Pain Measurement; D012720:Severity of Illness Index; D013997:Time Factors