Cancer fatigue is a feeling of extreme weakness and exhaustion during cancer treatment. At times, it may be a struggle to complete daily tasks. Fatigue can persist for weeks or even years.

Chemotherapy Affects the Whole Body
Chemotherapy
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Cancer and the side effects of treatment cause this condition. If your body is already weakened by cancer when treatment begins, then it is even more difficult to cope with the side effects.

These conditions are caused by cancer or cancer treatment, such as chemo-, radiation- or hormonal therapies:

  • Anemia—drop in red blood cells and the blood-forming cells in bone marrow
  • Poor nutrition and dehydration from nausea and/or vomiting
  • Less oxygen circulating in the blood because of anemia
  • Hormonal changes
  • Other factors:
    • Lack of sleep
    • Depression
    • Stress
    • Pain
    • Side effects of medications