Why doesn't your body swell if you drink a lot of water ?

You can overdose on water and once you past the point of taking too much water it makes you want to drink even more

Drinking too much water can result in a condition called ... When the body can't rid itself of excess water, cells swell to ... You may also feel nauseous if your body's water-to-sodium ratio is out of ... “Fluid doesn't just come from water, but from any beverage you drink, as well as many foods,” Every part of your body needs water to function. When you are healthy, your body is able to balance the amount of water that enters or leaves your body. A fluid imbalance may occur when you lose more water or fluid than your body can take in. It can also occur when you take in more water or fluid than your body is able to get rid of. Causes Your body is constantly losing water through breathing, sweating, and urinating. If you do not take in enough fluids or water, you become dehydrated. Your body may also have a hard time getting rid of fluids. As a result, excess fluid builds up in the body. This is called fluid overload (volume overload). This can lead to edema (excess fluid in the skin and tissues). Many medical problems can cause fluid imbalance: After surgery, the body usually retains large amounts of fluid for several days, causing swelling of the body. In heart failure, fluid collects in the lungs, liver, blood vessels, and body tissues because the heart does a poor job of pumping it to the kidneys. When the kidneys do not work well because of long-term (chronic) kidney disease, the body cannot get rid of unneeded fluids. The body may lose too much fluid due to diarrhea, vomiting, severe blood loss, or high fever. Lack of a hormone called antidiuretic hormone (ADH) can cause the kidneys to get rid of too much fluid. This results in extreme thirst and dehydration. Often, a high or low level of sodium or potassium is present as well. Medicines can also affect fluid balance. The most common are water pills (diuretics) to treat blood pressure, heart failure, liver disease, or kidney disease.

It is used to during sexual reproduction between humans