Sleepy legs may be caused by overwork, strenuous exercise, lack of calcium or low potassium, varicose veins, lumbar intervertebral disc herniation and so on. 1. Overexertion: Overexertion due to prolonged heavy physical labor or strenuous physical exercise will cause an increase in acidic metabolites in the leg muscles, so the phenomenon of sleepy legs occurs. 2. Strenuous exercise: when the legs after strenuous exercise, at rest, the muscles are in a state of strain and fatigue, you will feel the legs sore and weak, and there is a sleepy legs. 3. Lack of calcium or potassium trace elements: Due to irrational diet and insufficient nutrition, the human body lacks calcium or potassium trace elements, and the phenomenon of sleepy legs will also occur. 4. Varicose veins: patients with varicose veins in the legs may often feel sleepy due to poor blood circulation as a result of standing for a long time. 5. Herniated lumbar discs: Herniated lumbar discs can press on the nerves, which can also lead to the symptoms of sleepy legs. There are many reasons for this symptom. If it occurs repeatedly, you should go to the hospital in time and follow the doctor’s instructions to avoid serious consequences.