Upper body shaking can be caused by physiologic or pathologic factors. Pathologic factors commonly include: idiopathic tremor, Parkinson’s disease, hyperthyroidism and so on. 1. Physiological factors: when people are extremely frightened, nervous or angry, the sympathetic nerves will be overexcited, which will lead to muscle fascicle tremor, resulting in upper body shivering. If you are in a cold environment, shivering can produce heat to ward off the cold, which is a protective response. 2. Idiopathic tremor: It is an autosomal genetic disease, which is usually characterized by involuntary rhythmic tremor of the limbs, which can be manifested as shivering in the upper half of the body, and usually starts with the shaking of the hands. The shivering symptoms will become more obvious when there is mental stress. 3. Parkinson’s disease: belongs to the central nervous system degenerative diseases, in addition to the manifestation of the upper body or the whole body shaking, usually accompanied by slow action, muscle ankylosis and other manifestations. 4. Hyperthyroidism: frequent shaking of the upper half of the body can also occur, partly accompanied by palpitations, temper, easy to hunger and other high metabolic symptoms, which can be diagnosed through blood tests. All in all, if the upper body shaking and accompanied by other uncomfortable symptoms, it is recommended to consult a doctor in a timely manner, and follow the doctor’s instructions for treatment.