Medical research shows that after sweating a lot, the blood flow to muscles increases and the heart rate accelerates. If you take a bath with overheated water, hot water will speed up the blood flow, expand the swollen blood vessels and pores of the body, and increase the blood flow of the skin and muscles, so that the remaining blood is not enough to supply other important organs such as the heart and brain, leading to hypoxia in the body. Because hypoxia will have a great impact on the blood circulation of the heart and other parts of the body, it will bring greater danger to patients with heart disease and diabetes. If it is in hot weather, bathing with cold water after sweating will also harden the blood vessels and capillaries of the body. The correct way is to take a short rest and wait for the sweat to drip down before washing.