Stop when leg numbness occurs when the leg is leaning against the wall at 90 degrees. Leg numbness at this time often suggests the presence of lower limb ischemia. At this time, you should put your lower limbs up, lie in bed for a while, and then go down to the floor to walk or run. By this way accelerate the blood circulation in the lower limbs to relieve discomfort. When doing the leg against the wall 90 degrees exercise, we should pay attention to the following points to prevent the discomfort associated with the above: 1, exercise should be gradual, not to be able to do it overnight. In the beginning of the exercise, must be done for a short time, try not to appear leg numbness, leg cold, purple symptoms. 2, before and after the exercise to drink more water. By drinking a lot of water, reduce blood viscosity and prevent blood clots in the lower limbs. 3, before and after exercise, it is recommended that patients should do continuous aerobic exercise. It is generally recommended to do flat jogging activities. Only by doing sufficient warm-up exercises can the blood circulation in the body be accelerated and the blood pressure in the lower extremities be sufficient to ensure normal blood supply. 4, when doing such exercises must not be forced.