While exercise may be beneficial, scientists said, dealing with the free radicals that are an ultimate result of exercise can be a crucial consideration. Free radicals are highly reactive molecules produced in the body, often derived from oxygen, that carry an unpaired electron on their surface, making them prone to causing damage to other molecules they encounter. The ongoing, damaging effects of free radicals may be involved in aging and degenerative disease. Acute exercise increases metabolism and thus increases generation of potentially damaging oxygen radicals. Of particular interest is the role of antioxidants in fighting the damage done by free radicals.
Antioxidants react with and neutralize oxygen free radicals generated during normal metabolism.
Charlotte Tate, Ph.D., professor of pharmacology at the University of Houston, and president of the American College of Sports Medicine, also touched on the paradoxical nature of this issue. We need oxygen to live, but it produces free radicals. What the body has done to combat the paradox is to design enzymes and systems to scavenge free radicals. The key here appears to be that, when you age, you lose that ability, and the free radicals start doing bad things. In Tate's view, the body's natural scavenging ability may adequately protect it from free radical damage, but with age, the body may have difficulty defending itself and thus be more prone to free radical damage.