Tip 265: Beware of Cardiovascular Damage From Intense Endurance Training

I have just come across this article via the Charles Poliquin website that provides some good information on potential negative effects of long duration cardiovascular training.  http://www.charlespoliquin.com/AboutUs/Overview.aspx

The article gives food for thought. It doesnt say not to do it - just be mindful of recovery afterwards. 
I feel runners benefit from reading this kind of research as to be aware of what the body's reaction to this kind of event could be. 

Our choice of training runs are key to how we progress. After our long weekends away we may need a week to 10 days of non running sessions to get back to normal.
As a side note this isn't intended to scare people out of running/endurance events. From my point of view I have to make sure that the training I am planning will allow for the appropriate rest times after our training so that we remain healthy and arrive at the event in tip top condition.

Beware of cardiovascular damage from intense endurance training. There is evidence that the continual stress placed on the heart during intense endurance trainingcauses acute dysfunction in the right ventricle of the heart, the part of the heart that receives deoxygenated blood from the body and sends it to the lungs to pick up oxygen to fuel the working muscles. Acute dysfunction of the right ventricle may lead to enlarging or hypertrophy of this part of the heart, placing stress on the body.

A new study in the European Heart Journal  suggests that the acute dysfunction of the right ventricle that comes from intense endurance training occurs in a dose-response relationship such that longer duration training leads to greater impairment. This dysfunction is evident with arrhythmic disorders,  which appear as a rapidly beating or racing heart rate for a period of time.

The study measured cardiovascular function in 40 experienced athletes before and after an endurance event. Participants in the study had to perform at least 10 hours of intense training per week and have performed in the top 25 percent of the field in a recent endurance event. They did not have any evidence of cardiovascular risk factors. The study included marathoners, triathletes, ultra triathletes, and alpine cyclists, and the athletes’ cardiovascular function was tested a few weeks pre-race, immediately after a race, and two weeks after the race.

Results showed that the athletes demonstrated a significant immediate reduction in right ventricular heart function following the endurance race. The longer the endurance race, the greater the impairment in function. For example, the marathoners completed their race in less than 3 hours, whereas the endurance triathletes competed for an average of 5.5 hours, the alpine cyclists for 8 hours, and the ultra triathletes for almost 11 hours. In general, right ventricular dysfunction was greatest in the ultra triathletes and least in the marathoners, suggesting that the heart has a finite capacity to maintain the increased work demands of exercise.

The acute immediate reduction in right ventricular function in the athletes correlated with increases in biomarkers of myocardial injury, providing additional data that endurance training may not provide health benefits and does, in fact, cause repeated damage. Researchers expressed concern that athletes that repeatedly place their hearts under such stress will develop myocardial fibrosis, or a hardening of the heart tissues.

In this study, left ventricular function was not changed, which is not surprising since there is evidence that the work demand on the heart with increasing exercise intensity is greater for the right side than the left. Researchers suggest this makes the right side more susceptible to fatigue. 

Ten days after their races, the athletes right ventricular function did recover almost to the baseline level that was recorded two weeks prior to the race, indicating that the impairment is short term, but the concern is that habitually stressing the heart in this way and causing dysfunction may lead to longer term poor health outcomes. This concern is supported by the fact that right ventricular function and related biomarkers were all slightly lower than baseline at two weeks, although these reductions were not statistically significant. Also, reports of arrhythmic disorders in previous studies of endurance athletes lend support to the concern.

Take away from this study the understanding that long duration, intense endurance exercise is unlikely to be beneficial for health. Shorter duration endurance or “aerobic” exercise has not been shown to cause the same damage, but it does produce oxidative stress, which will lead to chronic inflammation and may impair organ function. Researchers note that regular exercise is essential for health and well being and has been shown to improve life expectance by seven years over a sedentary lifestyle. This is true—a sedentary lifestyle is one of the worst things you can do for health and longevity, meaning that any kind of physical activity, even aerobic, is better than sitting on your couch watching TV. But, I suggest that the ideal exercise for health, well being, and cardiovascular health is a resistance training program that includes intense energy system training for conditioning and weight management. To learn more about the negatives of endurance training, read The (Many) Negatives of Aerobic Training.

References:
La Gerche, A., Burns, A., et al. Exercise-Induced Right Ventricular Dysfunction and StructuralRemodeling in Endurance Athletes. European Heart Journal. December 2011. Published Ahead of Print.

Sharma, S., Zaida, A. Exercise-Induced Arrhythmogenic Right Ventricular Cardiomyopathy: Fact or Fallacy. European Heart Journal. December 2011. Published Ahead of Print.

Copyright ©2012

Good Footwear - what I just got reminded of (NICK)

This is in fact a story of a man who wore the wrong sized ski boots.

The day was Sunday 22nd Jan 2012.
Up in the Sierra Nevada mountains of Spain there are some good wide slopes to hurtle down. The fool (lets call him Nick) in this tale is a chap that should've known better.
He went through his check list before heading up to the slopes that morning.
Ski socks  - check
Ski's - check
thermal top - check
ski jacket - check
Ski trousers- check
Ski Boots - check
It turned out that all of his ski gear was borrowed from a friend. His main decision was whether the boots he was going to use would be of any use. He squeezed them onto his feet, snapped the clips down and stood. Nick (the fool) contemplated the following things, are they too tight? when I start to ski will my feet expand too much making these too small? Will I do any lasting damage to my lower legs and feet by having boots that don't fit me properly?
The one thing that that he didn't really ask himself was 'am I just convincing myself these will be fine so that I can save a bit of money?'

There was the sudden reality check for Nick as soon as he arrived at the slopes going up in the first gondola of the morning. He tried in vain to reassure himself that it's only for the day, he is man enough to take a little discomfort. In actual fact it turned out he wasn't :-(
About an hour into the day his legs had been working hard, feet getting hot, enlarging under the constant use and rapidly decreasing space inside the demon boots. His friends asking all the while if he was fine?? quite merrily replying 'yeah I'm sound - what nice weather it is as well', all the while saying to himself that 'if it's this uncomfortable now I can't wait for the next 3 hours!'

Turn, turn, turn, woosh...... 'this skiing is great' (what I will point out is that whilst I was skiing it actually took the pain away for a brief minute.....I repeat A BRIEF MINUTE)

What started as a fun day on the slopes for Nick started to take its toll...... he didn't need to be asked again about how he was doing, it was evident. He didn't even want to acknowledge the beautiful surroundings, the witty banter from his friends, all he could do was look down at his legs and apologise for the decision he had made as they were making him pay for his frugal choice!! 'Never again I promise, just stop hurting, I can't feel my feet!'
What he could feel is the boots compressing his right medial soleus (right calf) to the point of submission.
It finally happened where the numbness in the feet, the pressing on the calf's had gotten too much 'I can't go on! leave me here, I'll be fine' (actual words)

At a chair lift he had the relief that he had craved and it's not often you will see someone taking their ski boots and socks off on the mountain-yet here sat the fool for all to look at.

The End.

To be fair I have never experienced that level of pain through skiing or running. It painfully reminded me that the choice of footwear you decide to get has to be the right one otherwise you will end up on your backside, barefoot, unable to walk, nerves shot to hell, and not wanting to move. I couldn't actually raise (dorsiflex) my right ankle as the muscle had been squashed that much. It was very tender! Seeing me hobble along would've made you laugh......I wanted to cry! haha

I am actually in the process of deciding what trail shoe will be best for me during the transalpine event. This bad skiing decision was just over the course of a few hours. I will be running for 8 consecutive days through the Alps so I had better learn from this and pick the shoes that will give me the best chance of staying pain free, safe and able to keep going.
I understand how the body should move when you run and for me picking a shoe shouldn't just be one that is just based on comfort and cushioning- something most shoe stores use as their selling point and one that in the past I have fallen for.

I actually wear my Vibram Five Fingers quite a lot for weight training, sprinting and road running as these allow my feet to move in the way they are actually designed. The are a lot of bones, tendons, muscles, fascia and the like in and around the foot and ankle which in a conventional shoe design are 'protected' by thick soles which in actual fact block the natural movement of your feet which then has a impact on how your ankles, knees, hips and lower back react and move to the demands of running. (you can also link in upper body complaints to bad footwear)
What you get then are niggling injuries such as 'runners knee' or other excess loading complaints through the ITB, deep hip rotators, 'shin splints'.....the list goes on.
As much as I like and endorse barefoot shoes such as Vibram Five Fingers I know for my event that they won't be viable due to the terrain I will be running along. I need to find a shoe that won't affect my technique, is lightweight, doesn't impair my body's movements too much and one that protects my feet for my event.


The morale of the story - try not to borrow all of a friends gear as no persons body is exactly the same as another's. Also don't let the price of  footwear lead you into a bad choice. If it costs more than you have then save up the extra money to get the right shoes for your feet. Protect your feet otherwise you won't be out running at all.

Oh one more thing - learn how to run correctly, build up muscle through strength conditioning work and keep your muscles adhesion free and mobile (Sports massage, ART etc)


Don't be a fool...have the right tools (this is shockingly bad but it does rhyme! haha)

Training record - Dave

Have done 30 miles this week (Saturday to Saturday) - so just need to increase this to 200!

Not fit - (JK)

Last night saw me drag myself along for another run with the club. Luckily for me they had a ‘steady’ 5 miler on the cards. This suited my empty legs and gave the opportunity for the faster runners to increase the distance. I was somewhere in the middle!

The proof of me being worn out from Tuesday night was when the cycle home, which is downhill, turned out to ache my legs and that the nuun drink actually tasted good!

Roll on Saturday morning’s muddy run.