Is Eight Glasses Enough? How Much Water Your Body Really Needs

drinking_waterWe've all heard about how important it is to drink enough water, but few people understand why. How often do we really count the glasses of water we consume each day, and even if we did – how we know eight glasses is enough? According to the Mayo Clinic, water needs vary by individual and the question of how much to drink is not easily answered. Several studies have produced recommendations over the years, but how much water you drink will depend on other factors such as your activity level and where you live.

If you think the subject of drinking water unimportant, major U.S. healthcare organizations would disagree. On the "Nutrition and Eating" section of the Mayo Clinic's website is a section devoted exclusively to water. While even the Mayo Clinic staff says there is "no single formula" for determining your body's ideal fluid intake, it is possible to make an estimate.

Considering that 60 percent of your body weight is made up of water, it is not surprising that water performs some very important bodily functions in the body. In fact, every system in the body is dependent on water. It carries nutrients into cells, flushes toxins from vital organs and provides moisture for the ears, eyes, nose and throat. The body loses water in many different ways – through perspiration, breath and digestive functions – and this water must continually be replenished. When the body is dehydrated it can make you feel drained and tired.

How much water does your body need?

So how much water or fluid does the average, healthy adult really need? Assuming you are living in a temperate climate, The Institute of Medicine says that men need about 3 liters and women need about 2.2 liters. While it might be easier to stick with the well-known formula and drink eight glasses of water each day, it's important to remember that all fluids count toward the daily total. Not surprisingly, most health professionals would agree that water is better than sugary soft drinks and caffeinated beverages.

Which factors influence your water needs?

Runners, athletes and other active people may need to modify their total fluid intake, but there are other factors that influence the need for liquids. For example, if you live in a humid climate or take a lot of daily medications, it's always a good idea to drink more water. Pregnant women and nursing mothers should dramatically increase their fluid intake to meet the needs of the baby. Anything that causes fluid loss will require that you drink extra water to compensate. How much additional fluid you need depends on how much you sweat during physical activity, as well as the duration and type of exercise.

Is water always the best drink?

If you are engaging in long and intense bouts of exercise, it might be best to supplement your water intake with a sports drink that contains sodium. Drinks like Gatorade and Powerade contain electrolytes that help replace lost sodium during exercise, but it is also important to continue replacing fluids after an exercise session is finished.

Environmental influence on water intake

Do you sweat a lot in hot and humid weather? Does exposure to forced air heat make your skin dry in the winter? Do you breathe heavier in high elevations? All of these situations will require you to compensate by increasing fluid intake. Illnesses and other health conditions may require you to drink more water as well. Some stomach disorders, viruses, or bladder infections can require you to increase fluid intake, while many heart, kidney and adrenal conditions may require you to limit your fluid intake.

Can food be a good source of fluid?

While it's usually preferable to rely on drinking water to supply you with fluid, there is no denying that food contains water. For example, tomatoes and watermelons are at least 90 percent water by weight, but generally you can only expect to get 20 percent of your total water intake from food.

Beverages such as milk and juice are mostly water, and they also contain many valuable nutrients. However, if you are counting alcoholic and caffeinated beverages in your fluid intake remember that they can also be diuretics, meaning they can cause frequent urination. Water is usually our best bet considering it's inexpensive, calorie-free and readily available.

How to know if you're properly hydrated

Most people don't give their fluid intake much thought, but if you're wondering how much you really need, follow these tips from the Mayo Clinic. If you are drinking enough that you rarely feel thirsty and you produce about 1.5 liters of colorless or pale yellow urine each day, it's likely you are getting enough fluids. To prevent dehydration and ensure your body gets the fluid it needs, switch to water as your "beverage of choice."

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