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 

free radicals.png

2 people like this

User Feedback

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.


3 people like this

Share this comment

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

  • Similar Content

    • By tg821
      I have a 2018 KTM 250 SX and I have found my way to this forum because my ktm dealer is the only one in a two hour radius and does not know a lick about their own bikes. Also all of my family and friends have never had KTM's or Husky's. 
      I race motocross and am in the Intermediate/B Class, I weight 185 pounds. 
      So I was hoping I had some KTM gear heads on here to help me answer some questions. Warning: I am about to ask a lot of information so if some threads are already created just please point me to the link.
      My main goal is kind of crazy in my mind... I need more longer wrap out time in 2nd gear but need 3rd gear to be snappy out of turns so I do not burn up my clutch.  I ask this because a lot of the tracks I ride at in Missouri have pretty good size jumps right out of a sweeper or sharp turn. I dont like to hit them in 2nd right now because I get the Ronnie mac air boner affect in the air (because 2nd gear is very snappy and short). 
      1. Does anyone have any recommended adjustments for the RED power valve spring? (turns out/turns in?) Also what is the tool/socket I need to adjust, Robertson? What size?
      2. Any recommended suspension settings other than the manual? 
      3. My manual says the bike has a Performance ignition map that can be plugged in? Is that correct or is that only for the EXC models? 
      4. What rear tire has everyone seemed to run on this bike, 120 or 110? 
      5. Hate the long silencer exhaust, Should I run the FMF Shorty or the ProCircuit Shorty? 
      6. What size rear sprocket seems to work best for motocross with this bike? 49? 
      thanks for the much needed help! 

    • By lefa25
      The first episode of my new enduro series on YouTube: Zero To Hero.
      Lot's of stuff that gets usually edited out. Hope you guys enjoy it!
    • By dingerjunkie
      Hello All...figured I'd take a break from my own bike to ask a question related to my son.
      He'll be turning seven this summer, and has pretty much outgrown the '94 JR50 I built for him.  Both feet are flat on the ground with knees bent, with the shocks and rear seat posts in their highest positions.  Now, the JR is a notoriously short bike (18" seat height in lowest setting), and I'm thinking something in the height of a CRF50 or KTM SX50 Junior would be correct for him...and I can put a "tall seat" and risers on that to keep him on the bike if he spurts before the end of a second season.
      The challenge I'm facing is finding the right bike for him with the kind of riding he wants to do in our area.
      He wants nothing to do with the track, which is fine by me.  His request is to get into single-track/GNCC/TORCS-type aggressive riding with me here in central Texas (rocky, technical, cactus needles, hand-bashing, 10+ mile loops, 100-degree afternoons all summer long).
      If I look at a CRF or TTR, I get a heavy bike (hard for an almost-seven-year-old to muscle over rocks and tree roots) with spring-only suspension, drum brakes and a 10" front wheel that stinks outside of a groomed track or back-yard trail. 
      If I look at KTM or JKS (Polini clones) in the "junior" heights, I'm looking at a bike that fits, is light, has better suspension and brakes...but that would likely overheat quite a bit in slow technical sections and has a reputation of eating clutches even on a track.  I can't imagine how they'd hold up to partial-throttle off-roading over two seasons.  We won't be able to just walk back to the truck in the pits for spare parts like in the MX world...things get serious multiple miles from camp.
      If I go with a Chinese equivalent (SSR 70C), I get slightly better suspension that can be tuned, hydraulic brakes and the ability to run a 12" front wheel for better behavior in loose rocks and roots...but I also get worries regarding durability when we get serious off-road (legends of Chinese metallurgy and QC).
      So...to the parents that "do the desert" or get serious off-road with youngsters (at least at the "family enduro" level) in hot-weather environments...  What is the best option for a bike that will last two years, has about a 24" seat height and will work with an aggressive boy who wishes to attack "hill country" the way most boys want to attack a motocross track?
    • By Whopharded
      I wanted to offer back testimony after coming back from a 25 year hiatus and riding a year with the CRF-450.  My last bike from back then was an RM-125 which my wife sold while I was on a work trip to Japan all because a close friend of ours broke his neck and back in 3 places racing CC, narrowly escaping paralysis.... A story for another day.
      In the beginning I would have liked to have started back with a used 250 4-stroke but I leaned heavily on purchasing a more reliable 450.  I located a 2008 CRF-450R from a very reliable 'senior' seller whom had performed maintenance by the book and had the records to go with it.   The test ride it was big, fast, heavy and honestly scared me.   I truly felt that I would regret buying it but like so many we all know I threw better sense into the wind, paid the man, loaded the bike and drove off.  Wondering all the way if this could have been the worst if not the fatal decision I'd made in the last 25 years.  Not to mention, me being 56, I wasn't sure if riding at all was a good idea.
      Having admitted the bike was much bigger than me and my abilities I set the plan in place that I was only going to ride within my comfort and not push things.  So for the last half of 2017 I spent riding in a friend's large pasture and some gentle trails in the woods.  After the 1st couple of rides I was already looking online and in this forum ways to nerf the 450 to make it more manageable until I could get used to it and in general, riding again.  So here are the things I found that made the re-acclimation a success.
      Throttle Tamer - a throttle cam with a flat side that reduces the acceleration in the early stage of cracking it open. One tooth bigger on the drive sprocket Ride in a taller gear, 3rd and higher.  Literally lug it everywhere and fan the clutch when I need to. Those three in combination was what did it for me.  By taking brute acceleration out of the equation I could work on the mechanics of things I'd forgotten from 25 years past, et body position, weighting the outside peg, focusing far ahead instead of down at the wheel, ... etc.  After the snow finally melted I took the nerfed 450 to the local MX track.   I had so much fun!  I rode a total of 30 laps and just couldn't get enough.  The bike was nerfed enough so that I could get used to how it handled in the corners, ruts, whoops and some light jumping.   It was great!  I thought maybe this is what it was like to ride a 250, granted a HEAVY 250.  I think the key was picking a taller gear and use a lot of clutch.  Things seemed really mellow even though I was so sore for a week and loved it.
      After about the next 4 trips to the track I was getting noticeably faster and also picking a lower gear to jump farther.  Before the 5th trip out I decided to take out the throttle tamer, going back to stock throttle.  I was so ready and didn't even know it.  I was clearing the table tops and just about clearing doubles by accident.  The fun factor was up 3x by now.   After I got home from the 5th trip I was thinking that 2nd gear on the jumps was a little too low and 3rd was a little too tall.   So I went back to stock on the drive sprocket, one tooth smaller.  Please read that at this point the 450 is totally de-nerfed!  The training wheels were officially off!  It was perfect!  3rd gear on the jumps and clearing them so smooth and clean.
      So the take away. 
      Is it heavy? Well... yeah.  I can feel it when I'm riding it an getting it loaded/unloaded.  But hey, big girls need love too. Do I ride it to it's big bore potential? No... and I probably wouldn't a 250 to it's potential either. Am I glad I got the 450?  Given the approach that I took; Ride with nothing to prove to anyone and no need to rush the acclimation.  Nerf it so I could take time to re-learn the riding mechanics while not worried about the power.   I'd say, yeah!   If I could have bought a new and fresh 250 I may say different but this 450 is bullet proof and I can work with the weight.  While I do respect the 450 I'm not where I was in the beginning fearing it.  Cheers,
    • By wachterxc
      I would like to get my forks moving faster in order to respond to the smallbump-slowspeed chatter that bothers my ride. My valving is spot on (Race Tech Gold Valve), SKF seals are pretty fresh, and oil is at a good height. Ive come to the conclusion that im probably dealing with some stiction issues. Any tips on how to reduce this? Trying to find some low-budget solutions... (PLEASE dont suggest some kashima coating /ti-nitride fancy pantsy coating because im pennyless)
      Ive read some folks "polish" the inside of their fork tubes to reduce stiction. How do you polish these? Any special tools or technique?