Stay Hydrated!

Sure, you know it's important to stay hydrated during strenuous workouts. But do you know why? Or how much you need to drink?

Why? Your muscle contractions generate heat when you exercise. Your body sweats to reduce this temperature. Sweating out as little as two percent of your body weight (three pounds if you weigh 150 pounds) can adversely affect your metabolism and performance. Not drinking enough is often referred to as "dehydration." Dehydration can lead to fatigue, decreased coordination, and muscle cramps. In hot weather, it can also lead to heat exhaustion.

Serious atheletes will tell you that sufficient water intake can have a significant effect on their results. To the more typical user, who may just want to lose weight, the importance may not be so obvious. When the body uses stored fat for fuel, it creates waste. The excretory system transports this waste into the blood. Sufficient water intake allows the blood to further speed the transport to this waste for elimination. Drinking water during exercise also contributes to the process through which generating heat raises the metabolism and burns more calories. A rule of thumb among long distance runners is to drink 20 - 24 ounces for each pound they lose while running.

Sufficient water intake is also necessary for your muscles to contract efficiently. With insufficient water, your strength and performance is impaired. The effectiveness of your workouts is also reduced. A drop in body water volume of only 1% can cause a reduction in performance of over 10%.

Water also helps reduce the soreness you feel after an intense workout. Muscular contractions stimulate the muscles to release a chemical called hydroxyproline. This chemical irritates the nerve endings and causes the muscle soreness you can feel the next day. You flush this out of your blood with the other waste products, but only if the blood is sufficiently hydrated. Adequate flushing also speeds recovery.

How Much? First, we are talking about water, not alcohol! Sufficient alcohol intake can actually dehydrate you by making you urinate more than you would have otherwiee. Competitive runners will often drink a commercial product like Gatorade, on the theory that they need to replenish electrolytes, sodium, and other things excreted through sweating. However, this is not necessary for the casual exerciser so neither are the drinks.

Serious runners suggest drinking 6 to 8 ounces every 20 minutes during your workout. During longer workouts or running in hot weather, more may be necessary based on how much you sweat. This amount varies greatly between people, with some sweating as little as a quart per hour and others as much as 4 quarts per hour. It is easy to underestimate this amount because small amounts evaporate quickly on contact with the air.

You probably don't need to carefully monitor your water intake if you're just running on a treadmill for half an hour in an air-conditioned room. In any case, a few cold swigs after a workout is never a bad idea. The old adage holds true; drink before you get thirsty.