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Exercise and free radicals.

We've talked a lot about those mysterious "free radicals" over the last couple of years -- and about the antioxidants that combat them. As you may recall from high-school chemistry, the nucleus of an atom carries a positive electrical charge neutralized by the negatively charged electrons that surround it. Should the atom lose some of its negative charge, it becomes unstable and moves about, seeking electrons from other atoms to regain stability. Such an unstable atom is called a free radical -- and free radicals are constantly being generated in the body by normal and abnormal biochemical processes.

When these free radicals remove electrons from other atoms or molecules, the latter may themselves become free radicals -- and so the chain reaction goes on. By attaching themselves to atoms of oxygen, nitrogen, and carbon, free radicals cause damage by changing the structure and function of the molecules containing these atoms, leading to cardiovascular disease, certain cancers, and other diseases.

Because all cells require oxygen, our normal metabolism produces an abundance of oxygen-free radicals. Fortunately, the body also produces substances called antioxidants, which can give up electrons to oxygen-free radicals, without themselves becoming free radicals. This damage control system works fine as long as there is a reasonable balance between the production of free radicals and the production of antioxidants -- a balance maintained by the antioxidants in certain enzymes and other proteins, as well as those obtained from dietary sources.

Unfortunately, most of us don't consume enough antioxidant-containing fruits, vegetables, and legumes to maintain that balance properly, requiring the addition of such supplements as vitamin C and vitamin E to our diet.

So where does exercise come into the picture? Oxygen consumption increases greatly during aerobic exercise, and the production of oxygen-free radicals increases accordingly. Our normal antioxidant production is usually able to take care of these additional free radicals. Moderate exercise is helpful to the immune system. Too much aerobic exercise at one time, however, actually depresses the immune system by greatly increasing the production of oxygen-free radicals.

If you exercise regularly -- which we all should do -- it is advisable not only to enrich your diet with an abundance of fruits, vegetables, and legumes, but to take vitamin C and vitamin E supplements as well. Aerobic exercise is great -- but don't do it to the point of exhaustion. You'll not only feel better after engaging in moderate exercise, but your immune system will be much the better for it.
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Author:Brown, Edwin W.
Publication:Medical Update
Date:Apr 1, 1998
Words:406
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