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- The Journal of Physiology: Vitamin C and E supplementation hampers cellular adaptation to endurance training in humans: a double-blind, randomised, controlled trial
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Does Cardio Produce Free Radicals?
There's a lot of buzz about free radicals. These atoms form in response to oxidative stress, become highly reactive and can wreak havoc on healthy cells. Pollutants, cigarette smoke and pesticides encourage the production of free radicals.
Cardio exercise also produces free radicals, but there's no evidence that these types of free radicals are harmful to your health. With all the benefits of cardio exercise, free radicals aren't really worth worrying about.
Cardio and Free Radicals
During exercise, your metabolic rate rises. This is how you reap many of the benefits of exercise, such as improved weight management. This rise increases oxygen demands and produces free radicals.
The longer and harder you exercise, the more oxygen your cells need and the more oxidative damage occurs. Endurance cardio and very intense exercise can raise your metabolic rate up to 20 times its resting rate and significantly increase free radical production.
Antioxidants to the Rescue
If these free radicals are in fact dangerous to the body, don't worry. Your body naturally produces substances called antioxidants, which are molecules that are able to safely interact with free radicals and neutralize them before they cause damage.
Regular cardio exercise also increases antioxidant production by the body. One key to fighting off the free radicals produced during exercise is to exercise regularly and often. Eating a healthy diet is the other crucial element, as antioxidant vitamins such as vitamins E and C and beta-carotene are found in rich supply in fruits, vegetables, nuts, seeds and whole grains.
Athletes and Oxidative Stress
Many athletes who train often and strenuously take high-dose antioxidant supplements religiously because they believe it prevents oxidative damage and enhances performance. Whether or not this is true or necessary is widely debated. Extensive research has examined the subject, but the findings have been mixed.
However recent research has shown that antioxidant supplementation may even reduce some of the benefits of exercise and blunt performance. In a study published in 2014 in The Journal of Physiology, participants in their twenties who carried out an endurance training program received either supplementation with vitamins E and C or a placebo. In tests performed at the end of the 11-week program, participants who took the supplements showed some reduction in the beneficial physiological adaptations to exercise. Most importantly, they showed significant reductions in the markers of new muscle mitochondria production crucial for cellular energy production.
For the average person, a regular and balanced exercise program coupled with a nutritious diet should be enough to fight off excess free radicals from cardio exercise. Taking a multivitamin can help the body produce the antioxidant enzymes it needs to keep free radicals at bay. Athletes involved in more strenuous training can likely get all they need from a healthy diet. Talk to your doctor before you decide to take supplements.