Calf is always hot and not hot hand touch may be physiological (such as after exercise), may also be pathological, such as lower extremity arterial thrombosis, peripheral neuropathy and other conditions, need to be specifically analyzed. 1. Physiological reasons: physiological conditions, such as after exercise, due to increased metabolism of muscle tissue, there may be a self-conscious calf fever, but the skin temperature is not high, can be relieved after rest. 2. Pathological causes (1) Lower extremity arterial thrombosis: lower extremity arterial thrombosis can be accompanied by pain, numbness, sensory abnormalities, etc. Ultrasound examination of lower extremity arteries can be used to assist in definitive diagnosis. (2) Peripheral neuropathy: peripheral neuropathy refers to the structure and function of peripheral motor, sensory nerves or autonomic nerves, early sensory impairment is the main sensation of heat, numbness, tingling, etc., and in the late stage, there may be myasthenia, and electromyography and other tests can assist in the definitive diagnosis. The calf is always hot and not hot by hand, it is recommended to clarify the cause of the disease in a timely manner, and follow the doctor’s instructions to avoid delaying the condition.