Swimming is a popular leisure activity, especially in the summer. Many people enjoy spending a long time in the pool, thinking that the longer they swim, the better exercise they get and the more they can cool off.
Experts remind us that swimming for too long can also harm our health. The ideal swimming time should be controlled between one and a half hours to two hours, and even professional athletes generally train for only about two hours. The human body easily loses heat in water, so in order to avoid excessive heat loss, the body will have a protective reflex that causes the blood vessels in the skin to contract.
Therefore, the skin may turn pale when first entering the water. After swimming for a while, the blood circulation will increase, and the heat in the body will also increase, causing the skin to turn from pale to red. If one stays in the water for too long, the heat generated by the body will be lower than the heat dissipated in the water, and the body's temperature regulation function will be disrupted. This can lead to arterial constriction and small vein dilation, causing blood to stagnate in the subcutaneous veins. This can result in purplish skin, black lips, "goosebumps" on the body, and even muscle spasms.
Once this happens, the swimmer must immediately get out of the water, dry off, sunbathe, and put on clothes as soon as they feel warm, in order to prevent colds, muscle strain, and other symptoms.
