Endurance sports and heart health

Recently, a regular on our local group rides past away from a heart attack that he suffered during the ride. He was a very fit middle-aged man and I had just gotten to know him, it shocked me to the core. Anecdotally, this is the 4th endurance athlete I know of locally that suffered a heart attack and the 3rd to pass away from one.

Someone in our local group shared this video from Dr. James O’Keefe, a cardiologist with a personal background in endurance sports. You can see the video here. Granted the video is with reference to marathons, but I think it can apply to any endurance sport. In summary, he suggest that you should limit strenuous exercise to no more than 7 hours a week, especially if you’re over 40 years old. Given that his basis of non-strenuous exercise is walking, I would assume strenuous is anything over an endurance zone for cycling. In another video he suggests that shorter HIIT workouts are more heart-safe than long workouts at relatively high intensity, I would assume that would be something like sweet-spot or FTP.

I’ve heard about high-level endurance athletes having heart attacks and heart problems, but I guess I never realized that it also affects your average amateur cyclist too; it was like a gut punch. 7 hours a week is basically two 50 mile group rides, so does that just go out the window in light of this information? Do I go back down to low-volume training?

I plan on pushing my doctor to let me see a cardiologist, but has the effect of endurance training ever factored into your training plan and fitness goals? Prior to the recent events, I would have never thought I might be damaging my heart with endurance training.

EDIT: I should mention that I have a family history of heart problems. I started cycling a few years ago for heart health, but it has since morphed into a desire for a high level of cycling fitness.


I’m sorry to hear about the loss of a riding pal, that would be hard to deal with, especially knowing it could happen to anyone of you or us.

With regards to myself, I was experiencing excruciating headaches after short bouts of high intensity or maximum efforts. It prompted me to see a cardiologist and undergo a stress test. Thankfully I checked out as normal, but I do think it’s something we should all do periodically.

In terms of how you let this make an affect on your training is totally up to you, but I would encourage you get cleared by a doctor for peace of mind.


What is the old saying…we may be fit, but that doesn’t mean we are healthy (or something like that).

That said, I’ll take any potential risk to heart health by being active and fit over the greater risk of being sedate and overweight.


I’d rather die with my boots on.


Pick your poison, we are all going to die someday.


There is a very good thread on this on Slowtwitch.

There are other related and useful threads on Slowtwitch.

TLDR: probably worth getting stress tests and calcium scores done once over 35 or 40 or something. Fitness can be very high with substantial high-risk blockages. The only way to find out is have a heart attack or get checked with calcium score… I believe. Don’t quote me. I’m not an MD. Just a lowly sport physiologist approaching age 35 and who is getting some heart scanning done this summer :wink:


I’m switching to a more heart-healthy sport like Wingsuiting.


No one gets out of here alive….


I’m sorry to hear about the loss of your riding mate, one of the unpleasant aspects of middle-agedness is that you are confronted with death and your own health.

I’d be cautious jumping to conclusions, though, because perception bias could be a factor here: I reckon that many of your friends and acquaintances are cyclists and athletic. So if someone has a heart attack, they are likelier to also be a cyclist.

I’m not an MD, but as far as I understand aerobic exercise is, on average, good for health in general and the cardiovascular system in particular. Athletes also tend to eat healthier, and I reckon the risk of suffering a heart attack is actually lower as compared with the general population. I reckon that statistically speaking, overuse injuries (joints, etc.) are much more significant. Perhaps there is a tipping point if you do tons of sports, but you’d likely have to do a lot of exercise. Likely, it’d also depend on the type of rides that you do — a 4-hour Z2 ride will be different than a 3-hour 90 % effort.

Nevertheless, if there is a history of heart disease in your family, I’d get regular checkups and ask an MD, preferably one with a background in sports. Individual risk is different from statistical averages, you are not a statistic.


Five to one baby, one in five


someone call the gendarmes

frequency? I’ve not heard of this, had to look it up. looks like something worth footing the bill for.

I’m not sure the “everybody dies” response is particularly tasteful here. OP, I’m really sorry to hear that- I just had a friend who got into a (fortunately non-fatal) accident and the suddenness has really shaken me as well, so I can’t imagine what that must feel like.

I also think there’s space for enjoying cycling while being informed about the potential for risk and making adjustments as you feel comfortable, and that would start with a discussion with a specialist (preferably one that has experience with endurance athletes), along with the appropriate tests. No downside there :slight_smile:


Well it’s true. And so ask yourself what and who are important. Protect that which needs protecting. And other considerations that transcend this forum. And live everyday as if it’s your last. Sounds cliche, so flame away. :peace_symbol: Ciao.


Life is a challenge and if we listen to everything out there about what may happen……we could be frozen to inaction. There is always someone out there saying something negative about positive actions. We can do too much of anything. I wouldn’t change anything except if you notice an issue get it checked. See a doctor if you are concerned.

To give you the other side of things I was in my mid 50s and doctor told me I was high risk for a heart attack. Too much weight, etc. So I dropped 30 pounds in the next four months and started to cycle every second day. Next appointment to the doctor I am asked what happened? Am I sick? Not well? I said you told me to drop weight so I did. So for roughly the last 5 years I have continued to cycle. Cholesterol counts went to next to nothing. My eyesight improved? Don’t need glasses to drive….only had them since I was 18. My chronic disease, crohns has improved as well.

Cycling led me to change many items in what I was doing and how I live. I now have more energy. Aging issues as I am now 61 seem to not be as bad for me as my friends. In effect I have a history of being sick most of my life. I now feel great. All this came from starting to cycle. No idea how long it will last but I am enjoying myself and will continue to do so.

There are always two sides to every issue. Balance is the key.


Op sorry to hear that. Your response to question what you’re doing is normal.

Having a high level of fitness substantially improves my everyday quality of life. I would not consider training less to add years to the end of my lifespan. As far as heart issues are concerned, endurance exercise (and all exercise) increases heart mass as well as other factors related to the heart. There may be some relationship btw that and risk of heart attack.

This reminds me of when people tell me some story about how they know or heard of someone who was hit by a car and died / became a paraplegic. They say it as if I should take my road cycling and go to spin class at the gym instead.

Anecdotal evidence isn’t a good metric to use to make decisions. I do not believe there exists any statistical evidence that endurance exercise (above some hours per week) is associated with increased risk of heart issues.
However, I wouldn’t be surprised pro cyclists (or any real pro level athletes) have some issues later in life (they train 30-40hpw and restrict diet - abuse their bodies pretty hard).


Last year I got “Occam’s COVID” (Had severe shortness of breath symptoms but tests came back negative, which put me through a bunch of tests for things like pulmonary embolism etc. until my wife got the same thing) Anyways they discovered I had a borderline large aortic dilation of 44mm. I got tested for all kinds of genetic factors and they’ve come back clean and since then I’ve had it monitored every 4 months or so and there is no growth. The science is still very immature with regards to athletes, but it looks like 18+ years of pretty intense aerobic exercise has increased the size of my aorta. But nobody really knows if endurance athletes have any negative long term effects of this. Studies are just starting to take shape at this time.

The main thing I took away from this is that medical science is pretty good at understanding the heart for most people, but endurance athletes are significant outliers. Still, seeing a doctor once you start getting into the “masters” category is a pretty wise idea to see if there is anything noteworthy that you should be concerned about.


You sound exactly like a younger version of me.


Not sure! I can’t imagine more than every 5 yrs but I also know almost nothing on this topic.

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Sorry to hear that OP, must be tough to have a friend and fellow rider being taken away.

I’ve read through the slowtwitch thread that @Dr_Alex_Harrison linked, pretty scary stuff in there. Key takeaway for me is that:

A. Being fit, even very fit is no guarantee to be low risk
B. Possibly very bad outcomes and surprises are preventable if we take even small symptoms seriously and take appropriate preventive / diagnostic action
C. There is no rule of thumb or general conditions to rely on. When in doubt, talk to your cardiologist