This is going to scare you. Free radicals, molecules created by the breakdown of oxygen during metabolism, can wreak havoc by attacking cells. They’re linked to diseases and aging. Damn you, radicals! Because exercise requires increased oxygen consumption, it also frees those radicals. So, wait, exercise is bad now?
No, of course not. Research has shown that your body figures this out, and, effectively fights off the free radicals as it adapts to workouts. In other words: You got this. In fact, artificially suppressing free radicals via antioxidants may harm your ability to adapt to workouts as well as your insulin sensitivity, a benefit of exercise. So, wait, antioxidants are bad for exercisers now?
Not necessarily. Previous research utilized chemicals and moderately-high vitamin doses. There’s another approach. ‘‘Eat well,’’ the co-author of the original study told the New York Times. “Although this is not yet proved, it seems likely that antioxidants from foods, like blueberries, green tea, and carrots, may work in tandem with the body’s natural antioxidant defenses better than those from supplements.”
That brings us to the most recent study, which combines two of this century’s hottest fitness trends: CrossFit and green tea extract. (A previous study concluded, as if there was any doubt, that CrossFit elicited acute blood oxidative stress.) Sixteen physically active males were randomized into two groups. For six weeks while doing CrossFit (50-minute workouts, five days on, two days off), eight swallowed green tea extract, eight swallowed a placebo. Via blood tests before and after, various factors were measured.
Green tea extract had marginal benefits for aerobic capacity and brain health and a moderate advantage in reducing oxidation. It had a large benefit in boosting blood antioxidant capacity: 44% versus 24% for the control group.
It appears green tea boosts antioxidation in high-intensity exercisers without the downsides (though insulin sensitivity was not measured). Green tea, which is loaded with immune-improving polyphenols, seems, as the doctor hypothesized, to work in tandem with your body and not override it. We recommend 400-500 mg. of green tea extract, taken 2-3 daily, with meals. In addition to its many other health benefits—including reduction in the incidence of some diseases and a hike in metabolism—its teamplay in fighting free radicals let loose by exercise is yet another reason to go green.