Your body needs a certain amount of water to survive and function properly, but diet, illness, medications and underlying medical conditions can all cause your body to retain too much fluid, which is called edema. Edema can occur occasionally or be a constant symptom due to an illness. Once your physician properly diagnoses the cause of your fluid retention, recommendations can be made as to how much water is safe to consume. Some medical conditions require that you restrict water intake to prevent complications.
Daily Water Needs
Water plays many vital roles in the body. It keeps your temperature normal, lubricates and cushions your joints, protects your spinal cord and other sensitive tissues, and gets rid of wastes through urination, perspiration and bowel movements. Your body's need for water increases when you are fighting off an illness that causes vomiting, diarrhea or a fever; when you perspire during exercise; or when you are exposed to hot or humid weather. You can meet your daily water needs by drinking throughout the day and increasing your intake before and after exercise, or when exposed to hot weather, notes the Centers for Disease Control and Information. You want to drink before you feel thirsty, and your urine should be light yellow to clear in color. Dark-yellow urine might be a warning sign that you are not drinking enough. A general goal is to get about six to eight 8-ounce glasses of water each day.
Edema or fluid retention occurs when fluid gets trapped in the tissues in your body. Edema can be temporary due to the effects of gravity; after sitting, standing or being inactive for a period of time; during pregnancy; or a response to too much salt in your diet. Edema can also be a symptom of a serious medical condition such as heart disease, kidney disease, lung disease or a thyroid condition. In cases when edema is temporary, treatment involves limiting salt and alcohol intake, as well as elevating the area and using compression. In these cases, you do not need to restrict water intake unless your doctor recommends it. However, if the cause is an underlying medical condition, you might be told to limit how much water you drink each day.
Heart failure is diagnosed when your heart is no longer able to pump enough blood to meet the body's needs. This can occur when the heart is unable to fill with enough blood, or it is not strong enough to pump enough blood out. Heart failure can also involve a combination of the two and means fluids are not being pushed through the body normally, which can allow fluid to accumulate in the feet, ankles, chest, face and other areas. If you have heart failure, it is very important to follow your doctor's guidelines as to how much fluid you should drink each day because consuming too much can make your condition worse, says the National Heart, Lung and Blood Institute. No one set amount of fluid intake exists for all heart-failure patients, as the amount depends on your overall health, the severity of your heart failure and other treatments you might be receiving.
The kidneys have many jobs -- one of which is to control the balance of fluids in the body at all times. Fluids are constantly entering the kidneys, where they are filtered and either returned to the bloodstream or excreted. If the kidneys are not able to filter fluids properly, edema can develop. In the early stages of kidney disease, it is usually not necessary to restrict your fluid intake, but in later stages, your doctor might recommend restricting your intake, according to the National Kidney Foundation. Each case is different, so follow your physician's guidelines because getting dehydrated can be just as problematic.