The causes of sudden cold shivering may be related to a sudden drop in ambient temperature, or it may be caused by infectious diseases or hyperthyroidism. 1. Sudden drop in ambient temperature: common in the cold winter in the north, due to the sudden drop in ambient temperature, and then there is no good warming measures, it may lead to sudden cold shivering. This is a physiological factor, no special treatment is needed, by timely detachment from the cold environment, it is conducive to the disappearance of the symptoms soon. 2. Infectious diseases: commonly found in upper respiratory tract infections, pneumonia and other diseases, due to the presence of an infectious source in the body, which can easily lead to a sudden high fever, when the temperature rises, it may cause cold shivering, and may be accompanied by nasal congestion, runny nose and other symptoms. 3. Hyperthyroidism: because the patient’s body secretes too much thyroid hormone, leading to a significant increase in the body’s basal metabolic rate, when accompanied by a rapid heartbeat, sweating and other reactions, it may cause sudden cold shivering, which may also be accompanied by irritability, hyperphagia and other manifestations. Sudden cold shivering may also be caused by other reasons, if the symptoms are serious, you should seek medical advice as soon as possible, after diagnosing the cause of the disease, under the guidance of the doctor for treatment and adjustment.