title: The role of physical activity and physical fitness in postcancer fatigue: a randomized controlled trial.
abstract: OBJECTIVE
  Patients suffering from postcancer fatigue have both an inferior physical activity and physical fitness compared to non-fatigued cancer survivors. The aims of this study were (1) to examine the effect of cognitive behavior therapy, an effective treatment for postcancer fatigue, on physical activity and physical fitness and (2) to examine whether the effect of cognitive behavior therapy on postcancer fatigue is mediated by physical activity and/or physical fitness.
  
  
  METHODS
  Severely fatigued cancer survivors were randomly assigned to either the intervention (cognitive behavior therapy) or the waiting list condition. After assigning 23 patients in the intervention condition and 14 patients in the waiting list condition, they were assessed both at baseline and 6 months later. Physical activity was assessed via actigraphy and physical fitness was assessed by a maximal exercise test. A nonparametric bootstrap approach was used to test the statistical significance of the mediation effects.
  
  
  RESULTS
  A significant increase in physical activity was observed in the intervention group from baseline to follow-up, whereas physical activity did not change from baseline to follow-up in the waiting list group. Physical fitness did not significantly change after cognitive behavior therapy or after 6 months of waiting for therapy. Fatigue decreased more significantly in the intervention group than in the waiting list group. The mediation hypotheses were rejected.
  
  
  CONCLUSIONS
  Cognitive behavior therapy effectively reduced postcancer fatigue and increased physical activity but did not change physical fitness. The effect of cognitive behavior therapy on postcancer fatigue is not mediated by a change in physical activity or physical fitness.
authors.affiliation: Department of Medical Oncology, Radboud University Nijmegen Medical Centre, Geert Grooteplein-Zuid 8, 6525 GA, Nijmegen, the Netherlands. h.prinsen@onco.umcn.nl
authors.forename: H
authors.initials: H
authors.lastname: Prinsen
authors.forename: G
authors.initials: G
authors.lastname: Bleijenberg
authors.forename: L
authors.initials: L
authors.lastname: Heijmen
authors.forename: M J
authors.initials: MJ
authors.lastname: Zwarts
authors.forename: J W H
authors.initials: JW
authors.lastname: Leer
authors.forename: A
authors.initials: A
authors.lastname: Heerschap
authors.forename: M T E
authors.initials: MT
authors.lastname: Hopman
authors.forename: H W M
authors.initials: HW
authors.lastname: van Laarhoven
mesh_terms: D056044:Actigraphy; D000328:Adult; D000368:Aged; D015928:Cognitive Behavioral Therapy / Q000379:methods*; D005080:Exercise Test; D005221:Fatigue / Q000209:etiology / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009369:Neoplasms / Q000150:complications* / Q000503:physiopathology / Q000523:psychology; D010809:Physical Fitness / Q000502:physiology* / Q000523:psychology; D017741:Survivors; D016896:Treatment Outcome; D014850:Waiting Lists