During strenuous exercise, although the amount of perspiration will increase rapidly, and due to the acceleration and strengthening of breathing, the evaporation of water in the mouth and throat will be accelerated, and saliva secretion will be reduced, thus forming a dry throat mucosa and generating thirst, but the body is not necessarily short of water. Usually, rinse your mouth with water or drink a small amount of water.
If you drink plenty of water during strenuous exercise, it will swell your stomach, hinder diaphragm activity and affect your breathing; At the same time, it will also reduce the concentration of gastric acid and affect digestive function. After strenuous exercise, the body will consume more salt because of a lot of perspiration. At this time, drinking more water can not supplement salt, but will reduce the osmotic pressure of blood, destroy the metabolic balance of water and salt in the body, affect the normal physiological function of the body, and even cause muscle spasm.
Moreover, the heart activity is still intense after exercise, and drinking plenty of water will increase the circulating blood volume, thus increasing the burden on the heart.