VIP Sport Club

Water : Essential Nutrient

Healthy Tips

When you think about nutrition, what comes to mind? Most people think of vitamins, minerals and protein, getting enough calcium and iron, and not eating too much fat. Because it is so commonplace, it's easy to forget the most important nutrient of all: water.
Fifty-five to 60 percent of the body's weight is water. There's water in and around every cell, providing the perfect environment for cellular function. Water participates in many of the metabolic reactions that occur in the body. While we can survive for weeks without food, we can only survive a few days without water.

Our need for water increases when we exercise. During exercise, water is lost through increased rates of perspiration and respiration. It's important to replenish this water to avoid dehydration and possible heat stress.

Why is dehydration harmful?
Dehydration is especially dangerous during physical activity because it causes a decrease in blood volume and reduces the body's ability to get rid of excess heat, thus leading to possible heat exhaustion or even heat stroke. Dehydration certainly hurts sports performance, since it decreases maximal aerobic capacity. It also inhibits proper digestive function and is hard on the kidneys.

How much water should I drink?
Nutritionists advise that most people can meet their fluid needs with 6 to 8 cups of water, juices and milk daily. Alcoholic beverages increase fluid needs; one ounce of pure alcohol requires eight ounces of water to be metabolized.

A hot climate and physical activity also increase fluid requirements. A good way to see how much extra water you need when you exercise is to weigh yourself before and after your workout. (Sorry, the weight loss is not fat, but water.) Drink 2 cups of fluids for every pound lost. Urine should be pale yellow; the darker its color, the greater your need for water.

It's important to space out your fluid consumption throughout the day. Drinking a large amount of fluid at one time actually causes the kidney to excrete water, even though you may still be dehydrated.

Drinking a few extra glasses of water a day won't hurt you, so it's better to err on the side of generosity when it comes to water intake.

Don't you get enough water if you just drink when you're thirsty?
Unfortunately, thirst is not a reliable indicator of dehydration. When thirst strikes, most people drink just enough to relieve their parched throats. Your body may still need more water even though you are not thirsty.

Our sense of thirst becomes even less sensitive as we age. It is very common for older adults to experience chronic dehydration, with one symptom being constipation.

Are sports drinks better than water?
Sports drinks are helpful if you have become dehydrated. If you have lost more than 1 or 2 percent of your body weight during activity, then you are definitely dehydrated. For example, if a person who weighs 150 pounds loses more than 1-2 pounds during a workout, he or she is dehydrated. In this case, a sports drink helps a person rehydrate more quickly and more completely than just plain water. The reason for this is that sports drinks contain salts, which help your body hold water; they prevent the kidney from excreting water before you are dehydrated.

This sodium is of concern, however, for people who are on sodium-restricted diets. While some sodium is lost in sweat, the amount is quite small, especially if the person is acclimated to the heat. A typical sports drink contains about 50 to 100 mg of sodium. The National Research Council recommends a daily sodium intake of 1,100 to 3,300 mg for most adults. Some nutritionists have expressed concern that since most Americans consume 10 to 60 times this daily sodium requirement, sports drinks add insult to injury. They certainly aren't necessary for the recreational athlete who plays a leisurely doubles tennis game or a person who walks briskly for half an hour.