People experiencing fatigue may feel tired, lethargic, sleep or just lacking in energy. Fatigue is different from drowsiness, as it doesn't go away, even with more rest. Fatigue (physical fatigue or mental fatigue) is a common occurrence and complicated by the fact that fatigue is a normal healthy response to physical exertion or emotional stress. Fatigue could be the result of working, mental stress, over-stimulation and under-stimulation, depression and often boredom, disease or lack of sleep.  Read the full article