Feel sleepy and lack of the following common causes: first, participate in heavy physical labor or fitness exercise consumed calories, excessive loss of physical energy, muscle weakness, venous blood return slowed down the whole body muscle lactic acid accumulation caused by soreness, drowsiness symptoms, through muscle massage, bed rest, symptoms can be relieved in a few days. Second, sleep deprivation, daily sleep, if not more than 6-8 hours, the whole body will not be able to recover in time, the muscle is in a state of fatigue, so it will cause drowsiness, weakness symptoms, daily sleep should be guaranteed in more than 8 hours, can significantly improve sleepiness, weakness symptoms. Thirdly, anemia, the oxygen content in the blood of anemic patients is reduced, leading to ischemia and hypoxia of the whole body tissues, thus causing drowsiness and weakness of the body.