You’ve heard it a thousand times: Drink eight glasses of water a day. Even though this is just an estimated amount for most people, you don’t do it. You’re drowning in excuses–you don’t like the taste, it’s not convenient, you never remember. No big deal, you think–it’s not affecting your health. To understand why water is so important, you have to know what it does for your body. So grab a tall glassful, and read on.
Your body is one–half to four–fifths water, depending on how much body fat you have. Water makes up nearly 85 percent or your brain, about 80 percent of your blood and about 70 percent of your lean muscle. (because there are a lot of tissues that have less water, the average is about 50 percent.)
Every system in your body depends on water. Its roles are impressive. Water:
- regulates your body temperature.
- removes wastes.
- carries nutrients and oxygen to your cells.
- cushions your joints.
- helps prevent constipation.
- lessens the burden on your kidneys and liver by removing some of the toxins.
- helps dissolve vitamins, minerals and other nutrients to make them accessible to your body.
Besides helping your body run smoothly, there’s some evidence that water helps prevent certain diseases. People who have had kidney stones can prevent further stones from forming by drinking lots of fluid. And in one study, women who drank more than five glasses of water a day had a risk of colon cancer that was 45 percent less than others in the study who drank two or fewer glasses a day.
You lose about 10 cups of fluid a day through sweating, exhaling, urinating and bowel movements. Drinking water isn’t the only way to replace those fluids. You also get water from other beverages and even from foods. In an average diet, it’s estimated that solid foods provide between three and four cups of water a day. But because it’s difficult to estimate the amount of water solid foods contribute, it’s recommended that you only count fluids towards meeting your goal of eight glasses a day. But that’s only a ballpark estimate.
To better determine how much water you specifically need each day, divide your weight in half. Your answer is the approximate number of fluid ounces you should drink daily. Eight glasses is the average. Some people need more, while others can get by on less. Exercising or engaging in any activity that causes you to perspire and dehydrate increases your water requirement, as do hot, humid or cold weather and high altitudes. Keep in mind that sports drinks are better than water if you’re exerting yourself for 90 minutes or more at a time, 60 minutes if the activity is particularly intense or temperatures are very hot. Some beverages, such as those with caffeine and alcohol, are dehydrating, so if you drink them, you need even more water to compensate.