If we could do without O2, we could then live without antioxidants. Still, on this best of all possible earths, our cells demand oxygen and we have to live with the reactive consequences. Similar to the fire in your home, oxidation in your body can spring out of control. But instead of burning holes in your house's walls, metabolic oxidation can burn holes in your cell structures. Metal turns to rust via oxidation.
Muscles get their get-up and go from oxidation.
When a sliced apple turns brown-that, too, represents oxidation. Under most circumstances an atom of oxygen possesses two electrons that contentedly circle its nucleus. These free radicals contain an uneven number of electrons and, like drunk cowboys on Saturday night, are looking for trouble. As soon as free radicals are formed, the unleashed electrical forces can react with cell membranes and other cell parts, warping their structures, often destroying cell pieces in the process. To make matters worse, these free radicals may bond with other atoms or molecules, forming more free radicals in a chain reaction of microscopic havoc.