Dangers of High Intensity Training – Free Radical Production

Coach Robb

Dating back to 1775 and the research completed by a biochemist by the name of Joseph Priestly, it was discovered the importance of oxygen associated with sustaining life.  Ironically, he also discovered the dangers associated with the utilization of oxygen as it related to health and wellness.  As you breathe and your body utilizes stable oxygen (O2) molecules, and converts them to a free radical molecule.  Scientists now associate oxygen free radicals with every major chronic disease, including heart disease and even cancer.  Free radicals play a major role in the gaining process.  It is important to become aware of these potentially harmful substances, what increases their production and how to control them in order to reduce the negative effects on your health, performance and the aging process.  Increases in oxidative stress, whether from too much free-radical production, too little antioxidant activity, or both, speeds up the aging process. 

According to Dr. Maffetone, different levels of exercise intensity can produce varying amounts of free radicals.  Low intensity aerobic training (according to your personal heart rate zones), produce little or insignificant amounts of free radicals, and the smaller amount is more than likely well controlled through the body’s natural defense system, especially if enough antioxidants are present.  A well-developed aerobic system has its own antioxidant effect.  Fat burning and free radical breakdown occur in the mitochondria contained within aerobic muscle fibers.  With this in mind, people in better aerobic shape are more capable of controlling free radicals compared to those who are out of shape.  Research validates that individuals with a higher percentage of aerobic muscle fibers have more antioxidant production and therefore more antioxidant capabilities.

However, exercising at high intensity levels (above HR Z4) and lifting weights can have the opposite effect.  Such intense activity produces more oxidative stress – some research indicate as high as 120% over resting levels.  This is the result of physical damage to muscles, lactic-acid production and highter oxygen uptake, which may increase tenfold during activity.  Higher injury rates are also associated with increased free radical production.  Additionally, the development of more anaerobic muscle fibers means less aerobic mitochondria for free radical elimination.

This is (amongst others) why you will see the majority of your weekly volume based on aerobic effort.  Understanding intensity levels and their influence on your health, wellness and ultimately performance is another tool for Working Smart, Not Hard!

Yours in sport and health,

-Coach Robb 

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most studies on this have been inconclusive and need to be expanded immensely, however research also suggests that this only really applies to excessive and/or prolonged high intensity activity (60 min at 80%+ HR or Z4) which common sense should tells us is dangerous on various levels (overexertion, risk of injury, etc...) and science has already told us not to exceed 20min a day, 3-4x's per week.  Furthermore, it has been suggested that for the average athlete, a well-balanced diet and/or simply taking a multi-vitamin with antioxidants post-exercise is perfectly fine to counter act the increased production of free radicals in most cases.  advanced athletes are likely to have a higher tolerance.  

this is why legit athletes know how important pre and post workout nutrition and supplementation are.


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