Are we ultrarunning to heart failure?

If you're an ultra runner, you will have more than likely read "Born to Run", Christopher McDougall's bestselling book. It's an entertaining read, and I enjoyed it very much. I wasn't sold on barefoot running to be honest, but leaving that aside the book was was hastily consumed. Micah True, or Michael Hickman, or Cabalo Blanco (white horse) as he is know in the book became pretty famous after the book was published. Invited to talk all over the world about his experiences in the Copper Caynons running with the local Indian community there. He started a race in the Copper Canyon's to help raise funds too.

You will also have read that Micah true didn't come home from a run one day in March 2012. The ultra world mobilized in the search effort; Facebook lit up with posts about his disappearance. After a couple of days I thought, it's a shame but he's dead. I wondered what could have killed him. Getting lost and dehydrated? No chance, he knew the area well. Snakebite maybe? A possibility but unlikely, he would have had time to get back and seek help. After I had dismissed those, there really was only one possibility. He'd had suffered a heart attack I thought.

6 days into the search his body was found. Christopher McDougall had gone out to search for Micah. Though he wasn't the one who found the body, he wrote a good account of the search here. The end of the article hazards a guess that he had a heart issue, called Chagas disease. I would have liked it, if that had turned out to be what it actually was. However, I just had a nagging suspicion that maybe there was something more to it. I'd been reading more recently about Athletes Heart, a condition I myself have evidenced in more than one ECG over the years. I'm not knowledgeable enough about the heart's pathology to give you a detailed description. You can find plenty of information online, probably a better source that this Wiki entry, but you'll get the idea. Essentially the heart undergoes changes in response to endurance training, including left ventricle enlargement.

A week or two after his death the coroners report was published. I was pointed at the news story about it that bothered me. I read the title, and already knew what it was going to say. "Autopsy points to heart disease as the cause of ultra runners death". Heart disease I thought? This guy was a daily runner, and no mean ultra distance athlete and he died from heart 'disease'. I read the article and came on the information I hoped not to find. The article calls it heart disease, but the devil is in the detail.

"While medical examiners couldn’t point to the cause of the heart disease, they said True’s left ventricle, which pumps oxygenated blood to the rest of the body, had become thick and was dilated."

It's at times like that when I wish I was a cardiologist. I read it as though his endurance training had caused the left ventricle enlargement, which is ultimately what had killed him, aged just 58. Did he have another condition that contributed, was it another congenital defect not related to endurance training? I don't know? does anyone?

You always get people saying to you as a runner that "you'll ruin your knees", no one says to you "you'll ruin your heart" do they? For balance you have to say to yourself, 'what it I didn't run'? I'd probably die of coronary heart disease sitting on a couch eating chocolate bars right?

I posted the link to the story on the Beyond Marathon Facebook newsfeed and it prompted replies, mostly along the lines of "when your numbers up, your numbers up". It would be lovely if this was the case, but we do make our own fate. We increase our risk of various demises in our everyday lives. Driving a car, catching a tube, being a deep sea fisherman. Essentially what I am saying is that we alone decide what risk factors we introduce to our lives. Deciding to take up free climbing, hang gliding or high altitude mountaineering are inherently going to increase the likelihood of an early death if we do them often enough. Is it the same with running? If we run to keep fit, knocking out a few 10k's a week is that the ideal? On the Facebook feed, one of the 'flipside' replies included a link to a Endurance Corner where an American Doctor writes about Athletes Heart regularly and collects the results of studies. You can read all the articles here. The last and most recent article is perhaps the most interesting. Can too much exercise harm the heart.

Knowing very little about the heart as I do, I still share his conclusion that, like anything, you can probably to do much of a good thing and cause harm.

What I'd love to know, and so would the rest of the world, is what the perfect balance is? Or, if you have endurance trained, how long does it take to become chronic and irreversable, or can you reverse it if you stop after a few years? One of the studies cited, found that 50% of lifelong endurance runners (picked from a ‘100 marathon club’) had arrhythmia, versus 0% in the control group. 50%! There is no statistical insignificance there right?

I think there is probably a "Goldilocks Zone" for endurance training. Too little and the heart doesn't get the stimulation and strengthening it needs. Too much and it overdevelops and can lead to heart failure. Just Right ;there's probably a magical amount of endurance training, that is doubtless different for different people, where we keep the heart in the happy place, dead centre 'in the green' and away from the red zones on either side.

So how does this affect my outlook on running? Well, it does in all truth worry me. I've only been running since about 2006, so maybe if I ease back in a year or so, there is still time to keep my heart "healthy". Also, I don't knock out big distances every week, so maybe I have a little longer. In short, as it stands, no one knows. For the time being all we can do is keep an eye on the research, but with such a relative new sport, and such a small number of people (in comparison to other sports) involved in ultra running, it could be decades before there is enough data to tell us what constitutes "too much of a good thing", and by then it could be too late and half the world's ultra runners are checking out aged 60 or less.

Most of us will try and push this information out of our minds, thinking it'll never happen to us. Dare I draw a comparison to smokers, thinking the same thing about lung cancer?

Make no mistake, I love running and I'm not planning on hanging up my trail shoes anytime soon, but this is food for thought isn't it.

Would love to hear some of your opinions?