Fatigue is a precise term for tiredness or exhaustion. It occurs when someone undergoes an energy deficit and thus loses motivation for doing any activity. Usually, in normal condition a person feels fatigue after doing work (physical or mental) for longer hours but gets quick relief by taking proper rest. But if someone gets fatigued easily which lasts for an extended phase without any particular and relevant cause, it indicates a pathological situation. The diseases which may develop fatigue like symptom are: diabetes, hypothyroidism, anemia or even sleep related disorder.