Feet against the wall ninety degrees of harm including the following two aspects: First, for some obese people will produce arrhythmia and panic, shortness of breath symptoms, the human body is too obese, the use of this exercise will aggravate the pressure of the thoracic cavity and the abdominal cavity; at the same time this exercise will be aggravated by the veins to further accelerate the flow of reflux, which led to the cardiac load is too large. In the thoracic pressure and venous return under the dual role of too large, will cause the heart of the vegetative nerve disorders, and then lead to panic, shortness of breath, so for the over-obese people are not recommended to use this exercise. Second, this movement will aggravate the lumbar disc herniation and cervical disc herniation, for the lumbar disc and cervical disc herniation of the crowd, do this movement is not easy to grasp the cervical disc and lumbar disc curvature, so it may be in a short period of time will be caused by numbness of the hands, feet numbness of the symptoms. If you experience this symptom within a short period of time, it is recommended that you stop immediately and lie down to relieve the symptoms of numbness in your hands and feet.