Hydrate for Workouts

"Hydrate or Die," is the slogan of CamelBack, the company that first introduced hydration systems a few years go. Hyperbole aside, the importance of drinking enough water while exercising -- especially during the summer months -- cannot be emphasized enough.

When we exercise, we build up heat in the working muscles, causing our internal temperatures to rise. We cool ourselves by perspiring, or sweating. It is actually the evaporation of sweat on our skin that cools us, helping us maintain a cooler core temperature. That's why hot, humid conditions can be dangerous. When there is a lot of moisture in the air, evaporation doesn't occur and the sweat just runs down our arms and legs. We lose even more water and we need to drink more to keep cool and replace lost fluid.

The first drawback to loss of fluids is diminished performance. 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 work. As you become dehydrated, your total blood volume is reduced, and the oxygen-carrying capability of your blood decreases.

If you continue to exercise without proper fluid intake, you may experience a drop in blood pressure, dizziness and nausea, or even faint. These are the symptoms of heat exhaustion. Keep going, and your body's ability to dissipate heat is even further impaired, and you may suffer heat stroke.

During heat stroke, your temperature can rise above 105 degrees Fahrenheit. At that point, you no longer sweat, and seizures, coma or death may result. Remember: Blood not only carries oxygen to your working muscles, it carries it to all of your vital organs (like your brain), too.

How do you get enough water? Drink early and often during your workout. How much? How often? Six to eight ounces every fifteen minutes. That may sound like a lot, but it is only the equivalent of one large bicycle water bottle per hour. If you can't handle that much water at once, drink smaller amounts every ten minutes.

You should follow the same guidelines when exercising indoors. You can sweat a whole lot when spending 45 minutes or more on a stepper, treadmill or stationary bike.

Don't wait until you're thirsty to start drinking water. The sensation of thirst is triggered by the hypothalamus in the brain. It measures the concentration of salts in your blood. As blood volume goes down due to sweating, the concentration of salts goes up, and the hypothalamus sends the signal to start drinking. By the time this occurs, you've already lost a significant amount of fluid.

How can you be sure you're drinking enough water? When your urine is clear (meaning diluted) rather than yellow. It is important to keep drinking after your workout. Weigh yourself before and after a workout. For every pound of water you've lost (come on, you don't think you just lost a pound of fat, do you?), you need to drink one pint (16 ounces, or two 8-ounce cups) of water to replace it.

Don't forget that caffeinated beverages act as diuretics. (This means they make you go to the bathroom.) You need an additional eight-ounce glass for each cup of java you down to maintain proper fluid balance. Alcohol is also dehydrating, so for every beer or margarita you enjoy you need another glass of water to offset the deleterious effects of imbibing. This is in addition to the eight glasses of water per day that I know you are already drinking.

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