This is a provocative post from Dr. Mercola's site. I find him a great read and an advocate of self-help via a good diet, exercise and lower stress. In his opinion:
"Exercise is absolutely necessary for high-level wellness, but if you exercise too much it is clearly harmful and cancer seems to be a possible adverse outcome. My guess is that one's antioxidant threshold is exceeded or micronutrients are consumed at a level that cannot be easily replaced"
I too agree with the latest research indicating that heavy exercise results in a pro-oxidative state in the body- when I exercise I always supplement with r-lipoic acid before and after. I believe r-lipoic is one of the most potent and effective anti-oxidants available, and that you cannot take too much. We offer a liquid that is perfect to add to your water bottle, or like I do, just take a capsule before/after exercise.
Beware unstabilized lipoics. Testing has shown that some offer no bioavailability at all. Is that a risk you want to take?