title: Possible links between behavioral and physiological indices of tiredness, fatigue, and exhaustion in advanced cancer.
abstract: OBJECTIVE
  In this theoretical paper, we present the Edmonton Fatigue Framework (EFF), a new framework for the study of tiredness, fatigue, and exhaustion in advanced cancer.
  
  
  METHODS
  The Fatigue Adaptation Model (FAM), the starting point for the EFF, was drawn from a literature review pertaining to fatigue in depression, chronic fatigue syndrome, cancer, shift workers, and athletes published in the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Medical Literature Analysis and Retrieval System Online (MEDLINE), PubMed, PsychINFO, SPORTdiscus, and CancerLit between 1995 and 2004, and from seven qualitative studies conducted by our group. The EFF, an elaboration of the FAM, was constructed after an expansion of our literature review to 2006 and team discussion. The EFF provides new insights into possible links between behavioral and physiological indices of tiredness, fatigue, and exhaustion as they occur in both ill and non-ill states. In this paper, however, we consider only possible links in advanced cancer.
  
  
  CONCLUSIONS
  We propose that stressors associated with advanced cancer and its supportive treatment trigger declines in four systems -- cognitive function, sleep quality, nutrition, and muscle endurance -- and that these declines reduce one's ability to adapt. While these systems each likely has its own effect on adaptation, we propose that the most important and serious effects arise from interactions among declines in cognitive function, sleep quality, nutrition, and muscle endurance.
  
  
  CONCLUSIONS
  Interventions for fatigue have been limited by a lack of understanding about its etiology. Hypotheses arising from the EFF; suggest a new direction for further study that focuses on interactions among cognitive function, sleep quality, nutrition, and muscle endurance.
authors.affiliation: Faculty of Nursing, University of Alberta, Edmonton, Alberta, Canada. Karin.olson@ualberta.ca
authors.forename: Karin
authors.initials: K
authors.lastname: Olson
authors.forename: A Robert
authors.initials: AR
authors.lastname: Turner
authors.forename: Kerry S
authors.initials: KS
authors.lastname: Courneya
authors.forename: Catherine
authors.initials: C
authors.lastname: Field
authors.forename: Godfrey
authors.initials: G
authors.lastname: Man
authors.forename: Marilyn
authors.initials: M
authors.lastname: Cree
authors.forename: John
authors.initials: J
authors.lastname: Hanson
mesh_terms: D000222:Adaptation, Physiological; D003072:Cognition Disorders / Q000209:etiology / Q000503:physiopathology / Q000523:psychology; D005221:Fatigue / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D008962:Models, Theoretical; D009369:Neoplasms / Q000150:complications* / Q000503:physiopathology / Q000523:psychology; D009752:Nutritional Status; D010166:Palliative Care; D010807:Physical Endurance; D012307:Risk Factors; D012893:Sleep Wake Disorders / Q000209:etiology / Q000503:physiopathology / Q000523:psychology; D013312:Stress, Physiological / Q000209:etiology / Q000503:physiopathology / Q000523:psychology