The fluid in our bodies contains not just water but also various ions. When we sweat, for example, we lose water and ions from our bodies. POCARI SWEAT ION WATER contains a balance of water and ions that is close to that of body fluid, enabling smooth replenishment of lost moisture and ions. If you just drink water after sweating a lot, your body fluid becomes thin and diluted. In order to stop this trend, the body causes thirst to disappear, and sometimes stops absorbing water.