The pathophysiology of<unk>  is poorly understood. It may be caused by the<unk>  or the effects it has on the body, by the body's response to the<unk> , or by the<unk>  treatments.<unk>  is a common symptom of<unk> . Some<unk>  is caused by<unk>  treatments. This may show a characteristic pattern. For example, people on many chemotherapy regimens often feel more<unk>  in the week after treatments, and less<unk>  as they recover from that round of medications. People receiving radiation therapy, by contrast, often find their<unk>  steadily increases until the end of treatment. Proposed mechanisms by which<unk>  can cause<unk>  include an increase in pro-inflammatory cytokines, dysregulation of the hypothalamic-pituitary-adrenal axis, disruption of circadian rhythms, muscle loss and<unk>  wasting, and genetic problems. Additionally, some forms of<unk>  may cause<unk>  through more direct mechanisms, such as a leukemia that causes anemia by preventing the bone marrow from producing blood cells efficiently. A relationship between Interleukin 6 and<unk>  has been observed in studies, albeit inconsistently. Increased markers of sympathetic nervous system activity are also associated with<unk> .
Cancer-related fatigue
Idiopathic chronic fatigue
Functional somatic syndrome
AIDS fatigue
Chronic fatigue syndrome
Postmenopausal confusion
Food addiction
Exercise addiction