Almost all major systems of your body depends on water to function properly. Drinking plenty of water helps the body to regulate body temperature, prevent constipation, flush waste products out of the body, and perform many other important functions.
Most people, especially those who exercise in hot climates, are more concerned about not drinking enough water. You can alter the balance between water and sodium in the blood.
When the body is unable to get rid of excess water, which is said to be water retention. This happens with various medical conditions, for example. It can be dangerous, as it sheds on the balance between water and sodium in the blood.