Because the metabolic rate increases relatively during exercise, peripheral circulation increases capillary dilation.

At this time, going swimming and touching cold water caused the capillaries to contract suddenly, and the blood volume soared, which increased the burden on the heart.

However, decreased blood supply to muscles can cause cramps and other symptoms, and cramps are also very dangerous when swimming.

At the same time, the sudden contraction of skin pores caused by cold stimulation can also cause skin diseases.