Water: How much should you drink every day? Part 3

Dehydration and complications

Failing to take in more water than your body uses can lead to dehydration. Even mild dehydration — as little as a 1 percent to 2 percent loss of your body weight — can sap your energy and make you tired. Common causes of dehydration include strenuous activity, excessive sweating, vomiting and diarrhea.

Signs and symptoms of dehydration include:

* Mild to excessive thirst
* Fatigue
* Headache
* Dry mouth
* Little or no urination
* Muscle weakness
* Dizziness
* Lightheadedness

Mild dehydration rarely results in complications — as long as the fluid is replaced quickly — but more-severe cases can be life-threatening, especially in the very young and the elderly. In extreme situations, fluids or electrolytes may need to be delivered intravenously.

Staying safely hydrated

It's generally not a good idea to use thirst alone as a guide for when to drink. By the time one becomes thirsty, it is possible to already be slightly dehydrated. Further, be aware that as you get older your body is less able to sense dehydration and send your brain signals of thirst. Excessive thirst and increased urination can be signs of a more serious medical condition. Talk to your doctor if you experience either.

To ward off dehydration and make sure your body has the fluids it needs, make water your beverage of choice. Nearly every healthy adult can consider the following:

* Drink a glass of water with each meal and between each meal.
* Hydrate before, during and after exercise.
* Substitute sparkling water for alcoholic drinks at social gatherings.

If you drink water from a bottle, thoroughly clean or replace the bottle often. Refill only bottles that are designed for reuse.

Though uncommon, it is possible to drink too much water. When your kidneys are unable to excrete the excess water, the electrolyte (mineral) content of the blood is diluted, resulting in a condition called hyponatremia (low sodium levels in the blood). Endurance athletes — such as marathon runners — who drink large amounts of water are at higher risk of hyponatremia. In general, though, drinking too much water is rare in healthy adults who consume an average American diet.

If you're concerned about your fluid intake, check with your doctor or a registered dietitian. He or she can help you determine the amount of water that's best for you.

Source: The Mayo Clinic