What Causes Fatigue?

Them know why you feel tired? According to JA Hadfield in his book The Psychology of Power, said, "Most of the tiredness that we suffer from mental. In fact, rarely tiredness that is only caused by the Physical. "
Nearly 100 percent of the fatigue suffered by a worker who is in good health, are caused by psychological factors, namely emotional fator. 

Emotional factors that cause it are quickly tired of boredom, anger, feeling unappreciated by others, failure, always in a hurry, worry, and grief.
Fator-factors that make workers easy to get cold, their power is reduced, the head often dizziness. In short we are so tired, because these emotions cause nervous tension.