Marathon training 'may pose a heart risk'


  • The study looked at people training for triathlons and "extreme alpine cycling events" and they headline it as "marathon training...". I don't know about you, but I don't train "11 hours a day" for anything, even a marathon.


  • I train 11 hours a day on Facebook. image
  • "Conclusion Intense endurance exercise causes acute dysfunction of the RV, but not the LV. Although short-term recovery appears complete, chronic structural changes and reduced RV function are evident in some of the most practiced athletes, the long-term clinical significance of which warrants further study."

    I think the jury is still out...

  • Rubbish utter rubbish, the media have misrepresented the results again. After reading the study what it shows is that if you excerise flat out for over 10hrs (think Iron Man) then in a small percentage of people there may be an increased risk...but this is far outwieghed by the health benefits of excercise!
  • I guess the adage of excess in anything can be harmful can even apply to exercise but as most of us on here will read into the article it increases a risk for a small number of people who put in an incredible amount of hours of hard effort.  Unfortunately for all non runners/non exercisers this will be the newest article to quote at the Fish & Chip shop when they see one of us run past!
  • I spend all my daylight hours thinkin about the ladies.

    The ladies and the lovin'.

    The relevant muscle hasn't noticeably expanded in size, however.
  • Not an article drafted by one of the marathon or ultramarathon or triathlon participants at the Beeb, obviously, but by one of their jealous colleagues perhaps image
  • Dog in a hat AND a wig! Very swish... image
  • I wonder if the five athletes who showed "more permanent damage" also had other contraindications that would affect the health of their hearts?

    I'm just waiting for someone at work to point this out to me, "look, running IS bad for you. I will just sit here, munching my way through a packet of Hobnobs, smug in the knowledge that I'm not going to damage my heart by exercising too much" (or, in fact, at all) image

  • I'd like to see the actual research rather than the "soundbite" sensationalism in todays Mirror and the BBC site.

    I do recall a similar story a year or two back that centred on the ultra end of the scale rather than just marathons.

    My understanding was that it wasnt the training, it was the all out effort of the race itself that caused some changes.. in some people...

  • The research on this may actually be quite sound, it's just unfortunate headline-grabbing by the news. Most research on endurance sport has focused on the left ventricle, but recent studies in rats have shown the right ventricle to be the most affected. This latest study seems to be kind of a pilot study to see if there is any evidence of it in humans. I am going to sit down tonight and look through the paper and see what the numbers actually say.

    Straight off the bat, there are a few issues with the study. It is very small for one (40 individuals spread over 4 sports) - although they claim that this has 90 % power to detect a 10 % change. Also, it would have been interesting to include non-endurance athletes as a control group. There is also a large amount of ambiguity to the different time points; the "baseline" time point is 2-3 weeks before the event, so whilst some individuals may be tapering (and thus at a more "normal" level), some may be still training hard; and the "after event" readings were taken between 6 and 11 days post event - that's a big time window in this situation! Also, the differences shown between the groups are not entirely compelling to be honest - I am hoping to get hold of the raw data myself to have a play (this is kind of my field).

    But the authors have been very careful to make the point in all of the press-releases that this study does not say "marathon running is bad for you" (although that is unsurprisingly the message that the media are taking). They are simply saying that this indicates that right ventricular degradation is a novel effect to look into in endurance athletes in a clinical sense. Some people likely have a predisposition for it, so it would be good to know who those people are so that any necessary intervention can be taken. As it stands, no clinical outcome can be taken from this, it is merely the precursor of a much more in-depth longitudinal study that will shed more light on the situation. As the author says, some people are susceptible to tennis elbow, but people still play tennis.

    Incidentally, xine267 I believe that the five athletes who showed more permanent damage seem to be those who are older and have trained in endurance sports for the longest, although it is possible that there is some other confounding factor at play.

  • Sam, would be very interested to hear what conclusions you may be able to come to.

    Kicked it- there was someone who posted a link to sudden cardiac death in swedish orienteers a couple of months ago, in that case IIRC it found that training through illness was found to exacerbate heart problems. 

  • I'd be interested to read your findings too Sam.

    its an interesting area of research.

    We already know that intense endurance and aerobic training has an effect upon the heart and lungs, (which is kind of the point of doing it), so anything that sheds light on exactly what is happening I find illuminating.

    It is curious though that anyone could seek to draw even tenuous conclusions from such a small sample. I know the authors themselves are not making any great claims for this work, but why even bother releasing any findings at this stage?

    I am aware that there is other ongoing research being undertaken at various ultra races, (UTLD being one), with a larger sample of endurance athletes

    It amazes me how little we still know conclusively about the physiology of running.

  • Incidentally, the actual paper that the news report is citing is here. Unfortunately you have to have a subscription, but you can at least read the abstract.

    You may also be interested in the ULTRA (Ultrarunner Longitudinal TRAcking) study at Stamford, which I have participated in. It will not be studying things in quite so much detail on the clinical side of things as it is all based on surveys, but it should be quite illuminating if they are able to reach large numbers.

    I'll publish my findings this evening in case anybody is interested.

  • Kicked-It wrote (see)
    It is curious though that anyone could seek to draw even tenuous conclusions from such a small sample. I know the authors themselves are not making any great claims for this work, but why even bother releasing any findings at this stage?

    Time? Money? Although it is a fairly small study they have undoubtedly spent a notable amount of their own time and that of the athletes carrying out this research. They've have a duty to publish the work they have produced to the research body who funded the work.

    Whilst it is only a small study, and there is a large variation between the athletes they do nevertheless find a statistically significant difference which would be of interest to other researchers in the field. By publishing the work they are allowing others to follow it up in whatever way they see fit, that's how science works. If they had just sat on the work and didn't publish until they had generated a much larger data set it might of taken decades until the work saw the light of day and substantially inhibited any analysis of the work by others.

    As far as I'm aware the media aren't under any duty to publish cack though.

  • There is good evidence that endurance training increases your chance of certain heart problems. I know because I discussed it at length with the cardiac specialist who was trying to diagnose my heart problem. My eventual diagnosis was exercise induced atrial tachcardia, most likely caused by endurance training.

    Having had it treated by radio frequency ablation (that's up there on my list of freaky things that have happened to me) I'm back in training. I clearly don't learn image
  • Thanks for the additional info, Sam. I will have to see if I can get hold of the full text of the article from somewhere.

  • Having read the paper, I've written a post on this topic on my blog if anybody is interesting in reading it:

    As M.ister W says, evidence of endurance training affecting cardiac function isn't new, but the sensationalism of the media does not match the actual conclusions of the paper (surprise surprise...). I'm interested to hear anybody elses thoughts on this.

  • Excellent blog, Sam! Thanks very much for posting the link. I would love to see the same study done with a bigger sample size, and a control group of non-athletes.
    I also clicked on the DM article ... I wish I hadn't! Are there are people who actually believe that their heart only has an allocated number of beats for their lifetime and that exercise will "use them up quicker"?!
  • Unfortunately, yes, people do believe that xine267, Somebody goes even further and suggests that you only have a certain number heartbeats, breaths, steps, elbow bends, knee bends, etc in you. I stand by the way argument that, even if the heartbeat thing is true, our resting heartbeats are pretty damn low compared to most people's, so it probably all evens out...

    I just updated the blog to add in another study that I found quite interesting. This study suggests that smoking is beneficial for endurance athletes. It's lucky the media never got hold of that one! Just so you know though, this is in no way a study by a scientist claiming that endurance athletes should smoke. The author is "proving" an intentionally controversial point to show that if you do science badly then you can prove anything. In this case he has cherry picked a couple of example studies that show potential benefits of smoking to runners (loss of weight, increased lung volume, increased serum haemoglobin levels, etc.) and used them to argue an obviously incorrect hypothesis. But let's be honest, most people are going to read the title and make their judgement from that. 

  • NIce review Sam, cheers for that image

    I'm however not going to look at the DM site, as I prefer my blood pressure at it's current level. 

     My A level Biology teacher had a heart attack whilst I was at school. When he returned to work he said he wouldn't start exercising because of the limit number of heart beat argument. I'll however quote the 1st sentence from the editorial on the 'heart risk' article;

    "The cardiovascular benefits of regular exercise are established; individuals exercising regularly have an average life expectancy of 7 years longer than their sedentary counterparts. "

    Sarna S, Sahi T, Koskenvuo M, Kaprio J Increased life expectancy of world class male athletes. Med Sci Sports Exerc 1993;25:237-244

    Case closed.

    I like the smoking study too. Completely unrelated but my favourite academic paper is this one. linky

Sign In or Register to comment.