By [1] Tom Dell

For years, many of us have heard the oft-repeated advice of various experts: Drink at least eight glasses of water, eight ounces each, daily. Commonly referred to as the “8X8″ rule, this advice is well-intentioned. Upon closer examination, however, it would appear that consuming only 64 ounces of water might not actually be enough.

Your body is composed of between from 55 percent and 78 water, depending on your size. Water helps you maintain a normal body temperature, lubricate your joints, and eliminate wastes through sweat, urination, and bowel movements. When dehydrated, you can experience muscle weakness, cramping, lack of coordination - and potentially - heat stroke. While people can survive weeks without food, most only last a few days without water.

Water is lost from our systems through sweat, urination, sweating, and even breathing. Excessively warm weather, vigorous physical activity, or illnesses that involve vomiting or diarrhea can increase this normal loss. So, to be healthy, we all need to replenish water at a baseline rate and increase water consumption to compensate for above average depletion. For many years, that baseline was defined uniformly with the 8X8 rule at about 64 ounces, or two liters, a day for everybody. While the rule is widely accepted, however, it has proven hard to verify.

In his American Journal of Physiology article Drink at least eight glasses of water a day. Really? Is there scientific evidence for 8 × 8?, Heinz Valtin of Dartmouth Medical School states:

“Despite the seemingly ubiquitous admonition to ‘drink at least eight 8-oz glasses of water a day’ (with an accompanying reminder that beverages containing caffeine and alcohol do not count), rigorous proof for this counsel appears to be lacking. This review sought to find the origin of this advice (called ‘8 × 8′ for short) and to examine the scientific evidence, if any, that might support it. The search included not only electronic modes but also a cursory examination of the older literature that is not covered in electronic databases and, most importantly and fruitfully, extensive consultation with several nutritionists who specialize in the field of thirst and drinking fluids. No scientific studies were found in support of 8 × 8.”

How Much Water Is Enough?

So, if the 8X8 rule is unproven, how much water should we really be drinking? The answer depends on the source, but most seem to agree that the answer is more than 64 ounces a day.

According to a 2004 recommendation by the Institute of Medicine’s Food and Nutrition Board, women should actually consume 91 ounces of water daily and men should consume 125 ounces. This finding agrees with the United States National Research Council, which identifies the Reference Daily Intake (RDI) for water as 2.7 liters daily for female adults and 3.7 litres daily for male adults.

That might seem like a lot of water to drink every day, but bear in mind you can consume water in other ways besides drinking it. Food, for example, contributes from one-half to one liter to your daily intake. The metabolism of protein, fat, and carbohydrates adds another one-fourth to about one-half a liter.

The newest commonly accepted guideline for how much water you should drink takes into account your body’s size. Simply stated:

Daily Consumption = .5 to 1 ounce water X 1 pound body weight

So, if you weigh 120 pounds you would want to consume between 60 and 120 ounces of water daily. If you weigh 200 pounds, 110 to as much as 220 ounces. Obviously, that’s a big range. What should determine how much you actually consume within that range is how warm the weather is, how physically active you are, and whether or not you are losing additional water through sickness.

If in doubt, trust your own body. If you find yourself thirsty, drink more! Also pay attention to your urine. It should be light yellow in color and have little odor.

Water and Weight Loss

One of the benefits of drinking sufficient amounts of water is that doing so makes your metabolism run more efficiently, and therefore burn more fat. Sufficient stores of water also improve your kidney functions. According to various studies, some other ways in which water can help you lose weight include:

• Grabbing a glass of water instead of a snack. Your body can’t always tell the difference between hunger and thirst, so when you first feel hungry, try drinking water first.
• Drinking a glass of ice water before a meal. Studies have shown that this makes people feel more full and therefore consume fewer calories.

Water and Working Out

When you work out, you water consumption needs increase dramatically as you lose water through sweat and heavier breathing. Symptoms of workout-related dehydration include dizziness, lethargy, muscle fatigue, muscle cramping, and a loss of mental clarity. In contrast, if you consume sufficient water your workouts might seem easier. This is because your heart will not have to work as hard to pump blood and can more efficiently distribute oxygen and nutrients to your muscles.

Many sport authorities agree that drinking water before, during, and after a workout is essential to exercising effectively.

How Much Additional Consumption is Too Much?

It is not easy to do, but you can drink too much water, creating a condition called hyponatremia. In this case, the blood becomes excessively diluted, causing sodium levels drop. This might lead to confusion, fatigue, headache, and nausea. In rare and extreme cases it can result in coma and death. You would have to drink gallons of water to face this risk, however. To avoid it, simply make sure you drink small amounts of water throughout the day rather than all at once.

copyright©2009 [2] Scion Networks. All rights reserved. [3] Terms and Conditions | [4] Privacy Policy