Abstract
Fatigue is associated with cancer, but it also occurs in other illnesses and in work and leisure activities. This article is a report of part of a project comparing fatigue across ill and non-ill populations aimed at identifying the unique features of fatigue in individuals with cancer. The first stage of this work suggested that fatigue is 3 distinct but related concepts-tiredness, fatigue, and exhaustion-which led to the development of the Fatigue Adaptation Model. In this article, the authors report the findings of a qualitative study of fatigue in individuals with advanced cancer in active treatment and palliative settings. It is the first in a series of 5 papers intended to make the boundaries between tiredness, fatigue, and exhaustion more explicit. Here, the authors show that although tiredness, fatigue, and exhaustion are all manifested by the same 5 attributes (changes in emotional, cognitive, and muscular function; decreasing control over body processes; and decreased social interaction), the qualitative differences in the manifestations support the assertion that they are distinct states. This distinction is important, as interventions that could prevent, or at least delay, progression from tiredness to fatigue may be inappropriate for the prevention or delay of progression from fatigue to exhaustion.