Fatigue is a feeling of tiredness or exhaustion or a need to rest because of lack of energy or strength.

Fatigue may result from overwork, poor sleep, worry, boredom, or lack of exercise. It is a symptom that may be caused by illness, medicine, or medical treatment such as chemotherapy. Anxiety or depression can also cause fatigue.

By	Healthwise Staff
Primary Medical Reviewer	William H. Blahd, Jr., MD, FACEP - Emergency Medicine
Specialist Medical Reviewer	H. Michael O'Connor, MD - Emergency Medicine
Last Revised	January 12, 2011