The causes of hot calf soreness include excessive exercise, cold, varicose veins of the lower extremities. 1. Excessive exercise: running, long jump and other sports, anaerobic metabolism can occur, producing lactic acid. When exercising excessively, lactic acid accumulates in large quantities, causing soreness in the calves. 2. Cold: When the weather is hot, you like to blow cold wind or soak in cold water, which can easily lead to cold calf, which can cause muscle cramps and soreness. 3. Varicose veins of the lower limbs: when it is hot, blood circulation is accelerated, but the venous valves of patients with varicose veins of the lower limbs are damaged, and the venous blood return is blocked, thus causing soreness and distention of the calves. There are many other reasons for calf soreness in the heat of the day, if the calf soreness is not relieved, or accompanied by other symptoms, you should go to the hospital in a timely manner, clear reasons for targeted treatment.