Free radicals, forms of oxygen that are missing an electron, are actually not all bad.
Although they can destroy cell membranes and DNA, scientists have also discovered that they are also “good,” said Dr. John McDonald, a neurologist at the Kennedy Krieger Institute and Johns Hopkins. For instance, they help with cell signaling, the process of chemical communication that tells a cell, among other things, when to activate certain genes.
Exercise does generate free radicals but it also boosts production of molecules that sop up free radicals, said William J. Evans, an exercise physiologist at the University of Arkansas for Medical Sciences in an email.
In other words, regular exercise actually “trains the anti-oxidant system,” boosting production of natural anti-oxidants such as SOD (superoxide dismutase), catalase and glutathione, said Dr. David Systrom, Director of the Cardiopulmonary Exercise Laboratory at Massachusetts General Hospital.
Which leads to one of the hottest questions in exercise research: Should athletes take extra anti-oxidants, particularly vitamins C, E and beta-carotene? Some data suggest that performance and muscle recovery are enhanced with the supplements. But other data suggest that “anti-oxidants can become pro-oxidants – in other words, free radicals – when taken to excess,” said Systrom. “Nobody knows where to draw the line.”