Athlete's Heart: Just for Endurance Runners or for CrossFit Athletes as Well?

Athlete’s Heart is not only for the endurance athlete!

This article is one that is kind of near and dear to me. During a recent health issue, one of the residents noticed a heart murmur when they were listening to my chest. I didn’t think much of it to be completely honest because that wasn’t the reason why I was being seen. It was also mentioned to me kind of off the cuff and the attending hadn’t said anything when she examined me at first so I let it go.

But over time, as doctors were seeing me, they kept bringing it up.
They knew my athletic history and how I stayed pretty fit now.

The doctor then came in and told me they wanted to do an echocardiogram in order to make sure that I wasn’t at risk for sudden cardiac death… um excuse me?!

Turns out I have something called Athlete’s Heart

The heart is a muscle. So just like any other muscle in the body, if you stress it, it adapts. In my training in the gym, I often push myself into higher intensities and heart rates. This in conjunction with weight training means that I make my heart work really hard.

Athlete’s heart is an enlarged heart especially in the left ventricle. My body needs to pump a lot of blood to the muscle when I’m exercising. In order to do this effectively, it has to get bigger to accommodate the demand.

Commonly this was seen in endurance athletes. Athletes that stayed in higher than normal intensity zones for long periods of time tended to show this change. Often times though, marathon runners don’t even know that they have it unless they’re being checked by their doctor for something else.

It results in an abnormal heart sound when you listen to their heart beat. This was the murmur. It was interesting though because mine was called a “dynamic” murmur. What that meant was as soon as more blood was rushing to my heart (like when I’m exercising) the murmur disappears. For most people this is completely asymptomatic. It can also disappear if you become more deconditioned.

They’re Starting to Realize there is more to this than Marathon Runners

Recent research in the area of heart changes in response to exercise show that it might not be just marathon or endurance runners who could have these changes. Strength-based sports athletes and cyclists are popping up with the same issues.

The new research is suggesting that the heart is more likely to increase in size (called cardiac myopathy) based on the interaction of the time you spend exercise times the intensity of that exercise. If you’re pushing it hard in the gym for longer periods of time, your body needs to adapt.

With the rise of high-intensity interval training and functional fitness regimes, I started to wonder if we were going to see an increased prevalence of this. I LOVE training in a CrossFit style. It is the exercise program that I have stuck with for the last five years so this isn’t a bash at all. It’s more of a questioning. There is no research on this. I am an n=1 or a single story.

For most people with athlete’s heart, this isn’t dangerous. It causes a different heart sound but there is no signs or symptoms. The important thing to know though is that if some people are starting to develop shortness of breath or chest pain when they are working out at higher intensities, it might be time to get something checked.

Recently, in marathon runners, they have started doing screens for heart issues. This has been because of some incidences called “sudden cardiac deaths”. Basically, in certain individuals who are really well-trained athletes, they have an underlying heart issue that leads to a heart attack during sport. Note… this is DIFFERENT from athlete’s heart.

The reason why this is important is that this is what your doctors need to rule out. That is why I went for an echocardiogram (like an ultrasound of the heart). It was to see if there was something else going wrong that could put me more at risk. Ruling these things out are going to be important because it might affect your ability to do your sport (or else you just know your risks). I would have been heart-broken to be honest if someone had told me I wouldn’t be able to train the way I love to.

Thankfully all is well and healthy with me even though I have a funny heart sound. I guess it just means that my heart is jacked right?!

Want to see more of our heart related articles? Check out our article on Cardiac Rehab! Or our FAQ video looking at the appropriate blood pressure numbers!


Skielboe, A. K., Bandholm, T. Q., Hakmann, S., Mourier, M., Kallemose, T., & Dixen, U. (2017). Cardiovascular exercise and burden of arrhythmia in patients with atrial fibrillation – A randomized controlled trial. PloS One, 12(2), e0170060. doi:10.1371/journal.pone.0170060 [doi]

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Christina Prevett

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