The causes of chills and shivering without fever include hypothermia, infectious shock and endocrine diseases. 1. Hypothermia: If you have been in a cold environment for too long, involuntary shivering of the skeletal muscles will occur, which is used to increase body heat and belongs to the body’s self-protection mechanism. It is a self-protection mechanism of the body. It will be relieved if you pay attention to keep warm. 2. Infectious shock: The most serious infections lead to infectious shock, which will cause chills, pallor, drop in blood pressure, chills, etc. However, fever may not appear in the early stage or in very critical cases. 3. Endocrine diseases: This condition often occurs due to hypothyroidism and adrenocortical insufficiency, which leads to lowered basal metabolic rate and dysfunctional regulation. These are only some of the common causes. If the symptoms occur frequently and are not relieved after resting and keeping warm, you should consult a doctor for a clear diagnosis and standardized treatment as prescribed by the doctor.