The Beverage Your Body Needs Most

By Neesha Maria Bukht Choksy
Registered Dietitian and I.S.S.A. Certified Fitness Trainer
International contributing writer from Bombay, India.

Water

When we were kids in school our knowledge about water was initially restricted to the fact that it was great fun to fill up our squirt guns with water, at least until the principal caught us. Later we went on to learn that each molecule of water is made up of two hydrogen atoms and one oxygen atom. What we really didn't learn, however, was how much water we needed in order to be healthy human beings.

Why We Need Water

Our bodies are estimated to be about 60 to 70% water. Blood is mostly water, and our muscles, lungs, and brain all contain a lot of water. Water is needed to regulate body temperature and to provide the means for nutrients to travel to all our organs. Water also transports oxygen to our cells, removes waste, and protects our joints and organs. When we exercise, we build up heat in working muscles causing our internal temperatures to rise. During hard exercise, your muscles can generate 20 times more heat than when you are at rest. We cool ourselves by perspiring. It is this evaporation of sweat from our skin that helps us maintain a lower core body temperature. When there is a lot of moisture in the air, evaporation isn't an effective cooling means and we keep sweating and losing fluids in order to try and stay comfortable. If you did not sweat, you could cook yourself to death. A body temperature higher than 106°F damages the cells. At 107.6°F, cell protein coagulates (like egg whites do when they cook), and the cell dies. This is one serious reason why you shouldn't push yourself beyond your limits in very hot weather. As a result, we have to drink more water to replenish this fluid lost in the form of sweat.

Signs of Dehydration

We lose water through urination, respiration, and by sweating. The water we lose through sweating comes from blood plasma. Plasma is the vehicle for red blood cells, which contain the oxygen that muscles need in order to perform. As you become dehydrated, your total blood volume is reduced, and the oxygen-carrying capability of your blood decreases. The first drawback to dehydration is diminished performance. If you continue to exercise without proper fluid intake, you may experience a drop in blood pressure; feel faint, dizzy or nauseous. These are the symptoms of heat exhaustion. If you keep going, your body's ability to dissipate heat is further impaired and you may suffer heat stroke.

During heat stroke, your temperature can rise above 41 degrees Celsius. At this point, you no longer sweat, and seizures, coma or even death may result. Remember, blood not only carries oxygen to your working muscles, it sends it to all of our vital organs, like the brain.

Symptoms of mild dehydration include chronic pains in joints and muscles, lower back pain, headaches, and constipation. A strong odor to your urine, along with a yellow or amber color indicates that you are not getting enough water. (Note that excess riboflavin, a B Vitamin, will make your urine bright yellow.) Thirst is an obvious sign of dehydration. The thirst mechanism governs the feeling of thirst. The sensation of thirst is triggered by the hypothalamus in the brain. It measures the concentration of salts in your blood. As blood volume decreases due to sweating, your concentration of salts goes up, and the hypothalamus sends the signal to start drinking. However, this mechanism can be an unreliable signal to drink during workouts. Don't wait until you're thirsty to start drinking. By the time you feel thirsty, you are already dehydrated, so you need water long before you feel thirsty. By the time your brain signals thirst, you may have lost 1 percent of your body weight, the equivalent of 1.5 pounds (24 ounces) of sweat for a 150-pound person.

This 1 percent loss corresponds with the need for your heart to beat an additional three to five times per minute. This contributes to early fatigue.

How Much Water To Drink

A good rule of thumb is to take your body weight in pounds and divide that number in half. That gives you the number of ounces of water per day that you need. For example, if you weigh 160 pounds, you should drink at least 80 ounces of water per day. If you exercise you should drink another 8-ounce glass of water for every 20 minutes you are active. If you drink coffee or alcohol, you should add at least an equal amount of water. Coffee and alcohol are diuretics and remove water from your system. These should not be counted towards total fluid consumption. When you are traveling on an airplane, it is good to have 8 ounces of water for every hour you are on board the plane. If you live in an arid climate, you should add another 2 servings per day. As you can see, your daily need for water can add up to quite a lot.

Drink a glass of water every fifteen minutes during your workout. This may sound like a lot, but it is necessary to keep you hydrated. If you can't drink that much water at once, take smaller amounts every ten minutes. Seemingly tough at first, once you schedule it into your regular training routine, you will quickly adapt to having fluid in your stomach. In fact, the fuller your stomach is, the faster it will empty. Gastric emptying is greatly influenced by its volume. Emptying rate decreases exponentially as fluid volume is depleted. Therefore, an effective way to speed up gastric emptying is by maintaining high fluid volumes in the stomach. When you consume fluids, the rate of gastric emptying is speedy in the first few minutes, and then steadily slows down. To prevent this, you should consume small amounts of fluids frequently throughout your workout. Large amounts of water ingested quickly (such as 600 ml) during exercise, often causes gastric and intestinal distress. Around 400 ml of water can be cleared in 15 minutes for use, so it would be best to have 200-400 ml of water every 15 minutes for ample hydration.

After exercise, drink water to quench your thirst, and then drink even more. If you weigh yourself before and after your workout, drink 16 ounces of water for every pound of weight you lose after exercise.

You should follow the same guidelines when exercising indoors. Even if the air conditioning is on, you still sweat a lot if you spend 45 minutes or more on a stepper, treadmill or stationary bike. Don't assume you have to be outdoors for serious dehydration to occur. Thirst sensations change with age and older people, even athletes, become less sensitive to thirst. For example, 56-year-old hikers can become progressively dehydrated during just 10 days of strenuous hill walking. The younger, 24-year-old hikers remained adequately hydrated. This means older people, in particular, should carefully monitor their fluid intake.

The ideal fluid replacement beverage should encourage fluid consumption and promote fluid absorption. The best source for water is plain, pure water. If you exercise less than one hour, water should be fine. If you exercise longer than one hour, the fluid should also supply energy to your working muscles. In this case, drink about two to four cups per hour of fluids with carbohydrate concentrations of from 4 to 8 percent. Most sports drinks fall in this range. Sports drinks contain electrolytes and may be beneficial just look out for added sugar and calories that you don't need. Juices and sodas have a lot of sugar in them and aren't a good source, so if you drink them, they don't count towards your daily amount. Diet sodas aren't a good choice either. Herbal teas that aren't diuretic are fine during the day.

Carry a Water Bottle

It may be difficult to drink enough water on a busy day. Be sure you have water handy at all times by keeping a bottle for water with you when you are working, traveling, or exercising. If you get bored with plain water, add a bit of lemon or lime for a touch of flavor. There are some brands of flavored water available, but some of them have sugar or artificial sweeteners that you don't need. You might find it helpful to figure out how many gulps of water equate to 16 ounces, and even set an alarm wristwatch to remind you to drink on schedule. You'll also need to plan on having the right quantity of enjoyable fluids readily available. Do not be in such a rush to start your workout that you fail to bring with you the fluid that will enhance your efforts. All of these recommendations are, of course, in addition to the eight glasses of water per day that I assume you are already drinking!!

For any questions or comments on this article contact Neesha at fitforlife@rediffmail.com

 

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Title:	The Beverage Your Body Needs Most
Author:	Choksy, Neesha Maria Bukht
Publisher:	International Sports Sciences Association
Source:	Pro-trainer Online (Santa Barbara, Calif.)
Volume (Issue):	Apr 2005
Date:	Apr 2005
Page:
SIRC Article #:	S-977520

 

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