It is, however, one of the hardest terms to define, and a symptom of many different conditions. Fatigue, also known as ... I finally learned to rehearse an answer for them, and say, 'You know, I thought that, too, and I did some research and found out that the fatigue doesn't ... 80% of American women will suffer from adrenal fatigue at some point in their lives. Find out why you are so tired and what you can do to boost your energy! Chronic Fatigue Syndrome - Chronic fatigue "syndrome (CFS) is a disorder of unknown etiology, which probably has an infectious basis. Fatigue is often confused with tiredness. Learn