34°C is not hypothermia, but a low body temperature. Hypothermia is defined as a low fever, i.e. a body temperature of 37.3°C-38°C. Deep body temperature such as rectal temperature below 35℃ is called hypothermia. Normally, the rectal temperature is about 1°C higher than the axillary temperature, so 34°C is hypothermia. Hypothermia is a very dangerous signal that can directly or indirectly cause the death of the organism. Causes of hypothermia include hypothyroidism, long-term exposure to low temperature, which can lead to poor nutritional metabolism and dysregulation of the thermoregulatory center in the elderly. Patients with hypothermia mainly present with pale face, blue lips, chills and shivering, low blood pressure, slow heart rate and weak breathing. In case of hypothermia, patients should keep warm, drink hot soup and hot water, and take vitamin-rich and high-calorie food. If the patient has a primary disease such as hypothyroidism, he or she should seek medical treatment promptly.