Your Personal Fitness Plan
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Sweat: Your Natural Cooling System
Deodorant manufacturers would have us believe that perspiration ("sweat" to the rest of us) is the bane of polite society and is to be avoided at any cost. But as any active person can tell you, "working up a sweat" is a natural by-product of physical activity. Sweat is your body's natural cooling system. If you're active and you sweat, chances are your cooling system is doing its job -- if you don't sweat, it's time to watch out.
Sweat and Body Heat
At rest, normal body temperature is about 98.6 degrees Fahrenheit or 37 degrees Centigrade. When you engage in muscular activity, your body temperature rises (as much as 3 degrees during intense activity). Sweat (a combination of water, salt and trace amounts of iron) helps cool your body and prevent you from becoming overheated. When your body temperature rises, small blood vessels in your skin widen and draw heated blood to the surface. As the sweat evaporates, it draws heat away from the superficial blood vessels. The cooler blood then recirculates throughout the body, lowering internal body temperature.
Dehydration
Needless to say, if you fail to replace the water you lose in the form of sweat, you run the risk of becoming dehydrated, which literally means to become "dried out." Dehydration due to water loss during activity can have a significant effect on the body's performance. Since the body's energy production takes place in a fluid environment, the blood, muscles and organs all need water balance to work effectively. When water is drawn away from the working muscles, blood volume is decreased so the heart must pump harder to supply the same amount of energy.
Water Replacement
Water is better than any other fluid for keeping you adequately hydrated. The best way to avoid dehydration is to drink plenty of water, especially during long-term activity. Thirst alone may not be the best measure of your body's fluid needs. You may quench your thirst and still not have fully replaced your fluid loss. Generally speaking, two eight-ounce glasses of water two hours before, and one eight-ounce glass a half hour before exercise can keep you adequately hydrated. During extended activity, or if exercising in extreme heat, it's wise to drink at least three ounces of water every 20 minutes or so. It's also a good idea to weigh yourself before and after prolonged activity, and to drink 16 ounces of water for every pound lost. Even if you are not active, your body will sweat to regulate internal temperature, so be sure to drink at least six eight-ounce glasses of water daily.
Sweet Sweat
So, the next time you see an advertisement decrying unsightly perspiration stains or watch your carefully coiffed hair turn to frizz during your daily workout, your body's cooling system is doing its job.