Cycling Wed Exercise Healthy Living

Exercise and the heart — keep it simple

Exercise is a white-hot topic. We must talk more.

This comment on my Facebook page only strengthened my resolve to clarify things.

Not to be flip, snarky (or for that matter even just plain dense) but part of me is asking what’s the point of this? It brings up far more questions than it answers. In the end, we race bikes (with all the attendant risks whatever they may be). What am I supposed to do with _this_?”

I’m here to tell you that exercise is not confusing; it’s easy. You just can’t over-think it.

The too much exercise issue:

The now famous WSJ article, One Running Shoe in the Grave, finally succeeded in shining a light on the concerning observations made in long-time endurance exercisers. The brouhaha that emerged has been striking. Endurance exercisers, who know inflammation all too well, reacted defensively. Couch potatoes said, see…we told you so. Major media ran irresponsible headlines suggesting that running may be harmful to your heart. I hated that headline. Goofy sensationalism works against those of us who are trying.

I’m often asked why I write about the endurance exercise/heart-scar topic; what’s my agenda? Here is the comment I left on the WSJ article:

“As a heart rhythm doctor and a bike racer, the steady stream of seemingly super-healthy endurance athletes that populate my practice piques my interest. Why is it that someone so fit and so strong could develop the same diseases that sedentary overweight smokers get? Why is that heart CT scans of marathon runners look like those of smokers? Why is that Born-to-Run types suffer sudden death unexpectedly early? How do we ignore the multitude of studies on long-term endurance exercisers that show (otherwise unexpected) cardiac scars? It’s well known that scar in the heart predisposes to electrical abnormalities.

Here’s the problem for cardiologists: the overwhelming majority of the disease we see occurs in large part because of inadequate exercise. Most should exercise more. But like everything in life, too much of something is….well…too much.”

Let’s be clear about what this “new” data means: it suggests the possibility that those who exercise excessively over long periods of time may be putting themselves at risk for heart disease. This shouldn’t be controversial. It should be interesting and deserving of more investigation. Writing on his site, The Athlete’s Heart Blog, heart surgeon and triathlete, Larry Creswell said it well: “We need to keep an open mind as we continue to learn about the long-term cardiac consequences of endurance sport.” (If you haven’t already, you should read and Evernote this incredibly thorough and well-written post.)

This leads to the next question: How much exercise is too much?  I’m sorry. The answer is not knowable. That’s because humans are different. One person’s 8-minute mile is another’s 6-min mile. One person’s hour-long ride covers 25.4 miles, while another goes only 10 miles. Then there is genetics. Clearly there are varying degrees of susceptibility.

Back to my FB friend who asked about the point of all this…

Here it is friend: These revelations do not argue against exercise. They should inform patients and doctors of a POSSIBLE danger. Surely, the chance of ossifying (turn to bone) heart arteries or replacing heart muscle with scar warrants attention.

Humans aren’t newts. We have only one heart–that does not repair itself. Cell biologists remain a long way from gifting us the ultimate mulligan—stem cells.

Would being diagnosed with these afflictions cause you to make choices?

Long-time bike racer Steve Tilford answered this question well: (emphasis mine)

I am a bike racer. That is pretty much what I’ve done my whole life. It doesn’t necessarily define me, but it has molded me into who I am. I don’t plan on giving up this sport for anything. But, if someone could convince me that I might be in imminent danger, health-wise, if I keep competing, then I’d have to rethink the whole thing. I love the lifestyle, but without being alive you can’t have it either.


6 replies on “Exercise and the heart — keep it simple”

I’d like to ask you: What about the Tarahumara Indians of Mexico, who run constantly, and into their old age? They were profiled in the book “Born to Run”. They eat mainly a plant-based diet, and have no heart disease and no cancer, and live into their 80’s and 90’s. One big part of their diet is chia seeds which they eat to give themselves energy for their runs. They routinely run ultradistances. Could it be that they have some genetic immunity to the effects of overexercise that the rest of us don’t have? Or maybe something about the Western diet along with ultra endurance exercise is what’s really causing heart problems due to overtraining? Can we eat a healthy vegan diet and then run marathons or do Ironman races and have no ill effects? Maybe the problem is we use endurance exercise as a license to eat unhealthy foods.

“How much exercise is too much? I’m sorry. The answer is not knowable. That’s because humans are different.”
I understand your point; but aren’t there relative or perhaps qualitative indicators to help answer this question? For example, can’t heart rate be used to measure the intensity of exercise and indicate when someone is entering a high-risk level?

This is very well rounded and thank you for acknowledging that humans are different. I do have one question for you though, and I know that it’s not comparing apples to apples. If a patient came into your examining room who was overweight and sedentary, wouldn’t you warn him that he has a potential for damaging his heart with his lifestyle? Wouldn’t you advise him to lose a bit of weight and start to get a moderate amount of exercise? So if my pastor who is a very fit 59 year old marathoner came in, shouldn’t you mention that he has a potential to damage his heart with his 6+ miles a day of training? You did point it out as a consideration, but I’m wondering why it would only be a consideration. Again, it’s not apples to apples. A sedentary, overweight patient in your examining room would already be having rhythym problems.

Although exercise is essential to health, serious endurance training genereally isn’t pursued for “health” per se but to fulfill other goals — mostly the pride and satisfaction of being able to compete and come out on top. In fact, many people, myself included, have been willing to risk their health (and safety) for that goal. As a 61-year-old who has undergone a successful PVI ablation and thrilled to be back out on my bike, I struggle with the issue of what is “too much.” The sheer joy of being out on the road with my buddies is certainly worth a degree of risk. And just being aware of the risks (cardiac as well as texting drivers) is the key, I think, to keeping thing in some kind of balance.

Balancing benefit and risk comes in all shapes and sizes. I’ve logged 5K miles per year on the bike for the past 5 years or so, 97% of these as solo efforts. The past two years have been with a pacer in place…but recently developed Vena Cava Syndrome secondary to the leads. Do I need to learn to endure being pack fill in a peloton in 2013? 😉

I think the answer to the question about “What to do with this?” depends on: i) Whether you are one who exercises moderately on some regular basis (in which case that exercise is highly beneficial); vs ii) You exercise long hours and very intensely with little time for rest & recuperation (in which case you may be putting yourself at some increased risk from heart disease because of extra workload on the heart). Given huge variations between individuals in what is a “good level” of exercise vs what is overdoing it – our best “tool” for figuring out how much exercise is good vs how much is too much may be listening to ourselves (and to our body).

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