Water is essential to good health, but everyone’s needs are different. PHW researched some guidelines that can help ensure you drink enough fluids. How much water should you drink each day? It is a simple question with no real easy answer. Over the years many studies have produced recommendations but the truth is that your water intake depends on may factors, including your health, how active you are, and where you live. Although there is not an exact formula that fits everyone, it is important to know more about your body’s need for fluids and will help you estimate how much water you drink each day.
Water makes up about 60 to 70 percent of your body weight and is the body’s principal chemical component. Every system in your body depends on water! A prime example is how your body flushes toxins out of the organs, carries nutrients to your cells, and provides moist environments for your ears, nose and throat tissues.
Water is so important that lack of water leads to dehydration and is extremely harmful to your bodies overall health. Mild dehydration can drain your energy and make you feel tired.
Every day you lose water through your breath, perspiration, urine and bowel movements. In order for your body to function properly you must replenish its water supply by consuming beverages and foods that contain water. (PHW recommends fruits that are high in water like watermelon and strawberries).
So how much water does the average, healthy adult living in a temperate climate need? In general, doctors recommend 8 or 9 cups. Here are the most common ways of calculating that amount:
- Replacement approach. The average urine output for adults is about 1.5 liters (6.3 cups) a day. You lose close to an additional liter (about 4 cups) of water a day through breathing, sweating and bowel movements. Food usually accounts for 20 percent of your total fluid intake, so if you consume 2 liters of water or other beverages a day (a little more than 8 cups) along with your normal diet, you will typically replace your lost fluids.
- Eight 8-ounce glasses of water a day. Another approach to water intake is the “8 x 8 rule” — drink eight 8-ounce glasses of water a day (about 1.9 liters). The rule could also be stated, “Drink eight 8-ounce glasses of fluid a day,” as all fluids count toward the daily total. Although the approach really isn’t supported by scientific evidence, many people use this easy-to-remember rule as a guideline for how much water and other fluids to drink.
- Dietary recommendations. The Institute of Medicine advises that men consume roughly 3 liters (about 13 cups) of total beverages a day and women consume 2.2 liters (about 9 cups) of total beverages a day.
If you drink enough fluid so that you rarely feel thirsty and produce 1.5 liters (6.3 cups) or more of colorless or slightly yellow urine a day, your fluid intake is probably adequate. 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.
You may need to modify your total fluid intake depending on how active you are, the climate you live in, your health status, and if you’re pregnant or breast-feeding. All of these factors determine the amount of fluid your body is loosing by perspiring. Adding an additional 400 to 600 milliliters should be sufficient.
It’s generally not a good idea to use thirst alone as a guide for when to drink. By the time you become thirsty, you may already be slightly dehydrated. Further, as you get older your body is less able to sense dehydration and send your brain signals of thirst. On the other hand, excessive thirst and increased urination can be signs of a more serious medical condition. Talk to your doctor if you experience either.
- 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.
Although 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 low sodium levels in the blood, a condition called hyponatremia. 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 eat an average American diet.
There are several tools online to help you calculate and determine the appropriate amount of water intake that is right for you body weight and lifestyle. Take this short quiz! Or take a look at this easy Human Water Requirement Calculator!