# Does cycling increase the size of the heart? and if so, is it bad long term?



## aclinjury (Sep 12, 2011)

Cyclists have large hearts. But what does the medical world say about a large heart? Is this a bad thing as you get older? say in your 50 and 60?


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## bikerjulio (Jan 19, 2010)

I don't know the answer, but have a similar interest. I have been a serious runner, then cyclist for many years now. No obvious problems. My reading of the literature is a inconclusive.


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## sdeeer (Aug 12, 2008)

I am not trained (formally) in cardiac physiology. 

O'keefe recently published this: http://download.journals.elsevierhealth.com/pdfs/journals/0025-6196/PIIS0025619612004739.pdf

There was (obviously) some back lash about it.

I can't find the others but this is one: James O?Keefe on exercise: prescient or premature? « Alert & Oriented

And more here: The Athlete's Heart Blog: Don't Stop Running Yet!

My bottom line take home point....If you are doing it simply for the health of it, taking it to the extremes is not optimal.

But if you are like me....The limits of human physiology are there to explore. And I am competitive, so I will do what it takes (within reason) to show up on race day at my best.


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## Kerry Irons (Feb 25, 2002)

aclinjury said:


> Cyclists have large hearts. But what does the medical world say about a large heart? Is this a bad thing as you get older? say in your 50 and 60?


Enlarged heart in a non-athlete is generally a bad thing. Enlarged heart in an athlete is generally a good thing. Nothing is 100%.


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## aclinjury (Sep 12, 2011)

Kerry Irons said:


> Enlarged heart in a non-athlete is generally a bad thing. Enlarged heart in an athlete is generally a good thing. Nothing is 100%.


But the body of an athlete in his 50s/60s can't have capacity to compensate and resiliency as when he was in his 20s. I wonder if the heart will also shrink to match his decreased workload. If the heart stays enlarged, then is this something to be concerned about?


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## nOOky (Mar 20, 2009)

I have a history of heart issues and have cycled through all of them. What Kerry said is basically it. If you are concerned your doctor can tell a lot from a simple exam, if you're really concerned a treadmill test and an echo-cardiogram can tell you much.
You can do damage to your heart and body of course from too much exercise, especially if you do it repeatedly and don't allow your body to ever recover. I think most recreational cyclists are probably safe. The heart is a muscle, and being enlarged from exercise like any other muscle is good, being enlarged from having to beat rapidly to feed an overweight out of shape body is bad.


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## aclinjury (Sep 12, 2011)

According to the article by Sdeeer, the "athlete's heart" (enlarged heart) may not regress once the athlete stops competition



> _in elite athletes, cardiac__dimensions do not completely regress to normal levels_
> _even several years after the athlete has retired from_
> _competition and heavy ET._


I know a guy here who has a very good cyclist, has a very high VO2max, basically his heart seems healthy based on his cardio. Then one day he developed some sort of irregular heart beat. He went to the cardiologist, they ran all sort of tests on him over period of weeks. Nothing came back conclusive. The tests did indicate that there some sort of damage to his heart as blood biopsy showed something in the blood related to the heart being repaired (hence it was damaged). I dont' remember the exact detail. The cardiologist never gave him a definite causal, and just told him to take 2 months off training completely. He did that, and now he's back to training hard again. But he's always wondering if the condition would come back because they never figured it out why it happened in the 1st time around.


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## David Loving (Jun 13, 2008)

I'm not a racer. I'm 69 years old and cycle as a fitness thing - and for recreation. I've been a rider a long, long time. I had a gall stone attack last week and have to have an EKG before they can take the gall stones, and the gall bladder that makes, them out. So I had an imaging clinic do one - an RN who had not done one in a year did mine and they sent it to my primary care physician. Turns out something is "abnormal" and I see a cardiologist tomorrow. I'm praying that the RN caused the "abnormality". I'll ask him if cycling and working out for a lifetime has finally caught up with me, and report back. At my age one must expect the unexpected with health issues.:frown2:


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## Dave Cutter (Sep 26, 2012)

Between medical studies funded by pharmaceutical company's, well meaning believers in certain diets and or exercise routines, and out right snake oil salespeople.... even medical professional have a hard time sorting the science from... the rest.

I love cycling! Cycling gives me joy. And between quitting cigarettes, eating less fat and more fresh foods, of course... cycling near daily and just a tiny bit of jogging... I think I am healthier. I am NOT immune from heart disease. 

If you think you might be pushing too hard... you probability are. If you think your routine is OK... but your doctor thinks it's too much... your doctor is probability right.

If you (or I) do everything by the book and tests show the heart of a youngster athlete. Yet the heart fails while asleep... who would really be surprised.


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## plx (Mar 28, 2011)

Cyclist have the biggest hearts of all endurance sports
As long as you keep exercizing is no problem but if you stop all of a sudden i think it can be a problem. Try do reduce the load gradually


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## love4himies (Jun 12, 2012)

This is very interesting. Not everybody is cut out to do endurance sports. I've always wondered if those who just can't seem to do them have something different than those who find it easier???

Does anybody know if larger than normal lung capacity goes hand in hand with a healthy, enlarged heart?


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## plx (Mar 28, 2011)

It's proven that the exercise does get bigger with endurance exercise
People area always blaming poor genetics bla bla, everyone can get to the top if they have passion for it


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## aclinjury (Sep 12, 2011)

plx said:


> It's proven that the exercise does get bigger with endurance exercise
> People area always blaming poor genetics bla bla, everyone can get to the top if they have passion for it


you are correct to a great extent. Everyone can get to the top if they work hard. 

However, to win at the top will require some genetics though. Like they say in basketball, you can't teach a guy how to be 7'0". Lung capacity is also largely genetic.


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## aclinjury (Sep 12, 2011)

love4himies said:


> This is very interesting. Not everybody is cut out to do endurance sports. I've always wondered if those who just can't seem to do them have something different than those who find it easier???
> 
> Does anybody know if larger than normal lung capacity goes hand in hand with a healthy, enlarged heart?


I think everyone can do endurance sport. It's the "winning" that that everyone can't do.


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## Kerry Irons (Feb 25, 2002)

plx said:


> People area always blaming poor genetics bla bla, everyone can get to the top if they have passion for it


Sorry but this is pure nonsense. I certainly don't possess any hard data but I would be surprised if 1% of the population had the genetic potential to reach the top levels of any endurance sport (cycling, running, XC skiing).


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## bballr4567 (Jul 17, 2012)

A large heart in non-athletes is generally a symptom for another disease like COPD. If you see someone who is 400lbs and they really have n reason to have an enlarged heart. 

A large heart in an athlete is just a sign that the heart has grown due to use. Your heart is a muscle and has the ability to build new muscle although at a much slower rate than skeletal muscle. It can be cause for worry if its abnormally large (4-6 cm larger) but generally its not excessive enough to notice. Im talking maybe 1-2cm larger than normal. 


I say this as a radiologic technologist. We do 90% chest xrays so we are trained to know what to look for but cant diagnose anything.


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## OldZaskar (Jul 1, 2009)

I read some of those studies a few months ago. Not happy. Ended up "ignoring" them, e.g. not going let it impact my activities, etc. It came down to a simple idea...

"I do not seek to maximize the duration of my life...
... I seek to get the maximum from the duration of my life"


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## arai_speed (Aug 19, 2003)

OldZaskar said:


> It came down to a simple idea...
> 
> "I do not seek to maximize the duration of my life...
> ... I seek to get the maximum from the duration of my life"


Luv it!


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## sdeeer (Aug 12, 2008)

OldZaskar said:


> "I do not seek to maximize the duration of my life...
> ... I seek to get the maximum from the duration of my life"


By and large....your quote seems to be mostly true. While the amount of endurance exercise and dietary means we employ are not optimal for health (absolute longevity), they allow most of us to live longer and with better quality of life than our sedentary counterparts. 

I think most draw the line at factors that are known to reduce longevity substantially.

But many, as your statement illustrates, are willing to sacrifice some longevity for enjoyment of a particular activity.

The conflict in the policy making is prescribing the appropriate dose (of exercise or nutritional recommendations) that will increase the longevity and quality for the most individuals. 

Unfortunately, the data is a bit conflicting and is lost on the lay population. A part of me wishes that they were kept more in the dark or educated in the process of science and data to a greater extent.


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## aclinjury (Sep 12, 2011)

bballr4567 said:


> A large heart in non-athletes is generally a symptom for another disease like COPD. If you see someone who is 400lbs and they really have n reason to have an enlarged heart.
> 
> A large heart in an athlete is just a sign that the heart has grown due to use. Your heart is a muscle and has the ability to build new muscle although at a much slower rate than skeletal muscle. It can be cause for worry if its abnormally large (4-6 cm larger) but generally its not excessive enough to notice. Im talking maybe 1-2cm larger than normal.
> 
> ...



The real question is, once we stop or scale down our endurance activity, does our heart also now reduce in size? Preliminary data appears to say no, i.e., the heart stay enlarged (this is unlike skeletal muscle that under atrophy once we stop/reduce the exercise).

Another issue that interests me is the calcification of the aorta. Seems to me that this process is also irreversible.

What I do know is that when you do endurance sport, your heart does undergo some damage (like your skeletal muscle) and it also undergo fibrosis over time. The question is how much of this should we care to know about. Seems to me that the "athletic world" (especially the endurance folks) are not wanting to even know about what science has to say about it. For many endurance athlete, they just want to hear "more is better" (as in the more I exercise, the better it is for my heart).


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## tom_h (May 6, 2008)

Kerry Irons said:


> Sorry but this is pure nonsense. I certainly don't possess any hard data but I would be surprised if 1% of the population had the genetic potential to *reach the top levels of any endurance sport *(cycling, running, XC skiing).


I think you're being too generous , 0.1 - 0.01% might be more like it ;-)


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## JasonB176 (Aug 18, 2011)

sdeeer said:


> By and large....your quote seems to be mostly true. While the amount of endurance exercise and dietary means we employ are not optimal for health (absolute longevity), they allow most of us to live longer and with better quality of life than our sedentary counterparts.
> 
> I think most draw the line at factors that are known to reduce longevity substantially.
> 
> ...


Surely the obese/very fat among the sedentary population are at greater health risk than cyclists who are at their optimum weights. The percentage of obese at least in America is continually going up and the accompanying health risks and premature death. 

I think all this about exercise supposedly being bad for you is very dangerous information for the vast majority. I'm sure some sedentary people seize upon it to justify their laziness. Even *if* there is some truth to the idea that there is a possibility of negative health consequences for extreme athletes, leading an active cyclist's lifestyle must be far preferable to the average American's non-active one.


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## OldZaskar (Jul 1, 2009)

JasonB176 said:


> Surely the obese/very fat among the sedentary population are at greater health risk than cyclists who are at their optimum weights. The percentage of obese at least in America is continually going up and the accompanying health risks and premature death.
> 
> I think all this about exercise supposedly being bad for you is very dangerous information for the vast majority. I'm sure some sedentary people seize upon it to justify their laziness. Even *if* there is some truth to the idea that there is a possibility of negative health consequences for extreme athletes, leading an active cyclist's lifestyle must be far preferable to the average American's non-active one.


I think that's one of the points that Jason was making: Even if what we're doing - very intense endurance training - isn't the absolute optimal means toward optimal health/longevity, it's still much (!) better than what the vast number of Americans are doing... which is very little.


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## jspharmd (May 24, 2006)

This thread is mixing all sorts of medical conditions. The article cited by sdeeer suggests that cardiac remodeling secondary to repeated endurance events could increase the risk of arrhythmia development. This is completely different from dilated cardiomyopathy (heart failure with the observation of an enlarged heart). 

I also think that saying you ride a bike, so you should be healthier is oversimplifying the issues at hand. Intense and/or excessive exercise causes muscle damage. The idea that your skeletal muscle gets stronger after exercise is related to the body's adaptation to that previous damage. So, it makes sense that the myocardium (heart muscle) will be stressed (and damaged) with significant exercise. However, it doesn't seem that we have come anywhere close to understanding the consequences of long-term strenuous exercise. Most of the large epidemiological studies only provide correlations, they don't provide cause/effect data. 

So, read the studies with interest, take them with a grain of salt, and enjoy your cycling. I'm sure we will all be told when there is conclusive evidence that cycling is bad for your health. However, it will likely be too late for most of us, and we won't stop anyway because we love the sport.


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## tom_h (May 6, 2008)

Article appeared in NY Times's health section today,
_Can You Get Too Much Exercise?
_http://well.blogs.nytimes.com/2013/07/24/can-you-get-too-much-exercise , 
and it summarized a long-term study of 53,000 race participants in a 56-mile, cross-country ski marathon in Sweden.

Also compared & contrasted to some other human & rat research. Rodent research often won't directly predict human results, but enables invasive experimentation which for obvious reasons cannot be done on humans.

The full journal article on the x-country skiers is _not _behind a paywall,
_Risk of arrhythmias in 52 755 long-distance cross-country skiers: a cohort study
_Risk of arrhythmias in 52 755 long-distance cross-country skiers: a cohort study

Unsurprisingly, it's complicated:

" ... Kasper Andersen, a professor at Uppsala University and co-author of the Vasaloppet study points out, 'although we observed an increased risk of arrhythmias in the more trained athletes, physical activity and exercise have positive effects on the risk of other diseases' ... "


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## Sean.B (Jul 20, 2012)

I'm kind of surprised resting heart rate hasn't been mentioned at all in this thread. Maybe in all the articles posted that I didn't read, I'll just throw my .02 in. As your heart gets bigger from exercise, it's stroke volume also increases. Which is why you hear things on the news about people like Phelps, where they say his heart pumps twice the amount of blood as a 'normal' person. His resting heart rate is probably half that of the same 'normal' person as well. 

For what it's worth, my brother only does about 5 minutes total of 'cardio' a week, (He's a powerlifter), in the form of 20-30 second max effort prowler sled pushes. His resting heart rate is something like 50-52, I can't remember exactly. But that's 20-30 beats slower than whats considered normal, which again I'm not a doctor, but I'd like to think that means his heart is larger than a normal persons.


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## JasonB176 (Aug 18, 2011)

Sean.B said:


> I'm kind of surprised resting heart rate hasn't been mentioned at all in this thread. Maybe in all the articles posted that I didn't read, I'll just throw my .02 in. As your heart gets bigger from exercise, it's stroke volume also increases. Which is why you hear things on the news about people like Phelps, where they say his heart pumps twice the amount of blood as a 'normal' person. His resting heart rate is probably half that of the same 'normal' person as well.
> 
> For what it's worth, my brother only does about 5 minutes total of 'cardio' a week, (He's a powerlifter), in the form of 20-30 second max effort prowler sled pushes. His resting heart rate is something like 50-52, I can't remember exactly. But that's 20-30 beats slower than whats considered normal, which again I'm not a doctor, but I'd like to think that means his heart is larger than a normal persons.


I thought one of the main benefits of being fit is that, while intense exercise generates a heartrate with far more beats per minute, in the long run the fit person's heart will beat far less than his out-of-shape couch potato counterpart's. Because of this, on average, the fit person's heart will outlast the non-fit person's.


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## Herninscki (Jul 24, 2013)

That's it! I'm not riding anymore. After today.


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## velodog (Sep 26, 2007)

We all gotta die of somethin'.

And like OldZaskar said, quality is more important than quantity.


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## nOOky (Mar 20, 2009)

I have a history of arrhythmia and have had 3 ablations for atrial fib. I'll keep exercising as long as I can regardless of the studies.

Simple math says if I exercise 2 hours a day (pretty close) at 150 bpm and the rest of the time my resting heart rate is 60 bpm that's 97,200 beats a day. Assume I do nothing and my resting heart rate is 80 bpm that's 115,200 beats a day. That quickly adds up to 18,000 extra beats a day, or 6.57 million extra beats a year.

That is pretty typical for me right now as I'm training for a marathon and continuing to bike when I can, and it best resembles my actual values. I would assume even moderate exercise is going to save you _millions_ of heart beats in a single year.


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## Sean.B (Jul 20, 2012)

nOOky said:


> I have a history of arrhythmia and have had 3 ablations for atrial fib. I'll keep exercising as long as I can regardless of the studies.
> 
> Simple math says if I exercise 2 hours a day (pretty close) at 150 bpm and the rest of the time my resting heart rate is 60 bpm that's 97,200 beats a day. Assume I do nothing and my resting heart rate is 80 bpm that's 115,200 beats a day. That quickly adds up to 18,000 extra beats a day, or 6.57 million extra beats a year.
> 
> That is pretty typical for me right now as I'm training for a marathon and continuing to bike when I can, and it best resembles my actual values. I would assume even moderate exercise is going to save you _millions_ of heart beats in a single year.


Repped for math + science


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## phoehn9111 (May 11, 2005)

The primary actual cause of hypertrophy is transitory induced high blood pressure.
For instance if you are bearing down, tensing your core, and most significantly
if there are any periods of holding ones breath while straining. This causes to heart
to expand and adapt by thickening of the muscle walls to resist. Obviously most prevalent in weightlifting related athletics but to a fair extent cycling would not
be totally immune from this effect. My cardio said that in old age a hypertrophied
heart is more susceptible to heart disease and heart attack.


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## Pete_G (Oct 2, 2011)

This blog and website makes for good reading. A cyclist and heart doctor in one.

The Mysterious Athletic Heart

The detrimental cardiac effects of ultra-endurance exercise


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## looigi (Nov 24, 2010)

Pete_G said:


> The Mysterious Athletic Heart
> 
> The detrimental cardiac effects of ultra-endurance exercise


Sobering.


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## Mace2180 (Nov 12, 2012)

Well after all this learning I'm doing I have an answer. When it's time for a dirt nap it's time. I just hope heaven has clip less pedals. I was riding my schwinn super le tour today and it has standard pedals on it. I forgot how bad they suck!


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## Cableguy (Jun 6, 2010)

plx said:


> People area always blaming poor genetics bla bla, everyone can get to the top if they have passion for it


If this were a Disney movie, you might be right... but in reality, no. The difference between the performance the average person can attain, and that of a world class athelete, is staggering. In cycling this is probably something along the lines of a 50% difference in w/kg. 

I think generally speaking most people who watch sports fail to appreciate how superhuman and epic the performances of their sports heroes are. It always looks easier than it is, especially while sitting back in a lazy boy snacking on food. I guess it's a means of coping, the reasoning, "I could do that if I was paid to do it and I trained a lot". No, and even if your life depended on it in all likelihood you couldn't even come close.


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