Thursday, July 5, 2007
Sweat it out, it's good for you!
Exercise is an important part of a healthy lifestyle, and when we exercise, our water needs generally increase. As an individual becomes increasingly fit, his or her ability to sweat improves, which is a beneficial adaptation to exercising. The ability to sweat provides a natural refrigeration system to the body, cooling the internal temperature as it begins to rise during exercise. Actually, sweating is such an important and efficient method for the body to cool itself, an active person can lose a considerable amount of water through sweating and increased breathing during high-intensity exercise. In fact, it is possible for a 150-pound trained athlete to lose as much as six cups of fluid in a single hour of exercise!
This increased sweating and cooling mechanism of the body is a beneficial adaptation to exercise if a person takes measures to ensure he is re-hydrating himself sufficiently. If a person is not sufficiently hydrated, however, when excess sweating occurs, the overall volume of the blood is reduced. This can put strain on the heart and impair both exercise performance and the body's ability to cool itself. Therefore, it is essential to focus on replenishing fluid losses during exercise for good health�with the added bonus of improved performance as well. Many studies have demonstrated that well-hydrated athletes who drink fluids before and during prolonged exercise are able to perform better.
A major factor that influences the rate of evaporation is the relative humidity of the air around you. If the air is humid, then it already has water vapor in it, probably near saturation, and cannot take any more. Therefore, sweat does not evaporate and cool your body as efficiently as when the air is dry.
Finally, when the water in the sweat evaporates, it leaves the salts (sodium, chloride and potassium) behind on your skin, which is why your skin tastes salty. The loss of excessive amounts of salt and water from your body can quickly dehydrate you, which can lead to circulatory problems, kidney failure and heat stroke. So, it is important to drink plenty of fluids when you exercise or are outside in high temperatures.