|MadSci Network: Medicine|
Dear Harbour School,
Do swimmers Sweat? That certainly is a good question, the question however is very dependant on the environment that one is in, so, keeping that in mind lets turn our attention to finding out just what sweating is and the role the environment takes.
Some of the information was taken from the site Understanding The Science Of Sweat.
Sweating is the primary means for the body to cool during exercise. Skin blood flow increases significantly during exercise. Blood flowing near the surface results in cooling by both conduction and convection.
Sweat glands become active as body core temperature rises. One liter of sweat is generated during the expenditure of about 500 kcal. Studies have shown that training increases both sweating and skin blood flow. Humans generally produce 200 milligrams of sweat through their underarms in one hour at room temperature. This can increase to 700 milligrams during strenuous physical exercise, at times of emotional stress, or in warmer climates.
An individual who is heat acclimated may perspire almost twice as much as an un-acclimatized individual. One of the effects of acclimatization is to allow an individual to begin perspiration earlier in the course of exercise, this allows for a quick, effective and efficient beginning to heat dissipation and alleviation of early heat buildup. Each gram of perspiration that evaporates cools the body by 0.6 kcal. Acclimatized individuals may produce up to 30 g/minute of perspiration. This would allow for considerable cooling.
As we noted, the environment has a major impact on heat loss. Humidity, playing the largest role, but temperature, of course, also plays a major factor. These both impact upon heat loss via conduction and convection, besides the impact on evaporation of perspiration. The worst possible conditions would be a hot, humid, windless day, following a cool spell.
So now that we know the background of sweating we can utilize this information to determine If "swimmers sweat ?", the first part of your question. From the information we have gleaned it makes sense to say with some certainty that the degree of sweating experienced by a swimmer is determined by the temperature of the water. If the water is sufficiently cool enough then the sweating would be very minimal. However, if the water approaches body temperature than it would not sufficiently cool the body and the swimmer would experience a great deal of perspiration. Remember, that a study was done to show that the body will produce 200 milligrams of sweat through the underarms in one hour at ROOM TEMPERATURE and this will increase to 700 milligrams during strenuous physical exercise.
We can now answer the second part to your question, "And if so, where does the sweat go?
The sweat is obviously going to go into the environment, if you are out of the water then it will evaporate due to the cooling effects of the air, or it will end up on a towel or some other article of clothing. Since you are still in the water then it will end up in the water, this sound pretty gross but the amount you are perspiring is certainly very minimal in relationship to the body of water you are in.
So there you have it, you will probably not want to go swimming in a tiny pool with a bunch of other people now that you have the facts concerning perspiration and swimming, but remember, a pool is treated with chemicals to minimize problems associated with contamination. So, forget the perspiration and take a dip.
I want to thank you for taking the time in sending the Mad Sci a question and I certainly hope I have answered your question sufficiently.
June Wingert Baylor College of Medicine Department of Comparative Pathology Houston, Texas
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