Technical FAQ: Cyclists and heart issues

Lennard Zinn includes many of the notes he's received in response to his column on the heart issues endurance athletes can face.

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Dear Readers,
Since writing about it in my column three months ago, I have received much mail from other cyclists who have experience with heart issues. I have not known what to do with it all, as it’s way more than could fit in a normal column. However, it seems that the sheer volume of it and variation of experience might be of interest to a lot of people who are passionate about riding bikes.

We all know that on a very basic level, riding a bike is super good for us, and we also all have had the experience of overdoing it from time to time. And we may never know at what point we might be doing irreversible damage. But given that most of these writers first experienced these issues while riding, that certainly at least points to some relationship between cause and effect. And the letter from a cardiologist and bike racer is a word of caution against extrapolating too far about cause and effect.
— Lennard

Dear Lennard
Thank you so much for the great article you wrote on the Heart. I think this will finally make me stop trying to ride like I did when I was younger.

Two years ago at age 67, I had a heart attack whilst riding. Fortunately for me, I did not go into cardiac arrest and I was very near to a great hospital in Arlington, Virginia. Within 20 minutes, I was having a stent installed. At the time, just like you, I was incredulous that this could happen to me. I thought I was so fit for my age and only six months prior to the attack, I was on my vacation in Boulder doing all the favorite climbs: Lee Hill, Superflag, Ward; during the climbs my heart was up in the 190s, and it felt great. I always thought this was a good stress test and felt that if there was a problem it would certainly show up under fire, not during an easy ride to coffee!

Two months after the heart attack, I retired and moved to Loveland, Colorado. I feel sad that I can no longer attack the climbs but I am grateful to still be able to get up them. I keep trying to go harder but I am definitely not the same rider I was three years ago.

Your article will change the way I ride. I will accept my age and my 150 BPM max and just enjoy being on the bike.
— Gary

Dear Lennard,
I’ve read with heightened interest your cardiac issues and would hope you could shed some light on the issue. I am a 56-year-old ex-competitive road cyclist, skate skier, and until recently I competed in endurance mountain biking competitions. After an incident during training of an extended elevated heart rate during a rest phase, I was diagnosed with “athlete’s enlarged heart” that was observed with a chest scan. I also see a traditional Chinese doctor who has her western medical degree, and she feels it’s a compression of the cardiac nerve from an enlarged heart. The only advice I have been given is not to exercise so much. I know you are not a medical professional and would not misconstrue your advice as medical advice and each case is different, but what are your thoughts on exercising at lower heart rates? Utilizing my AT number and a monitor, I’ve continued to exercise three times a week. I’ve read that anything over two hours could also be a risk factor. This is a point of contention between myself and my wife.

Without the extensive medical resources and having a high deductible health plan, I’m limited in my ability to pursue an in-depth analysis.

I apologize for the length of this email but I’m interested in your thoughts and experiences, beyond what I have read, in dealing with this issue. Thank you for your time.
— Jeff

Dear Jeff,
My thoughts on exercising at lower heart rates is that it can be done and can be quite satisfying. And focusing on technical aspects can keep it interesting. For instance, I still do group ’cross training rides, but since I’m now slow on the pedaling sections, I work on my technical skills. I’m constantly improving my cornering to try to close gaps that open on the pedaling sections, and I’m improving my bunnyhopping (my goal is to be able to clear two successive 40cm barriers consistently by the time I’m 60 — three more years).
— Lennard

Dear Lennard,
I thought you’d be interested in my situation from a long-time fan and owner of your books! The first time I experienced 240 bpm tachycardia was in 1988 as a 19-year old at CC doing Captain Jacks in Cheyenne Canyon of Colorado Springs. Since then I’ve not really medically addressed this at all.

Before and after my first problem episode (all of which have been almost identical to each other now this 29th year of having these episodes about monthly or two times per month or more!), I raced USCF and collegiate nats and did Cat 2 Superweek a few years. I trained and raced very hard as a teenager in 1985 — until as a collegiate racer, I first experienced the symptoms. I remember clearly thinking that my own very hard effort caused my heart to malfunction temporarily. I quit racing and riding hard from 1990 until I took up riding and some racing again in 2003. I still continue to ride and I can still go hard.

Since that day I have had hundreds of episodes of 200+ bpm tachycardia. Here is what I’ve learned:

— My tachycardia symptoms are temporary, they come on very quickly without warning basically, although you can set conditions where it will be more likely to occur. You know what it feels like. Suddenly your heart starts superficially going haywire, but then you realize its a rhythmic, super fast fluttery rhythm.

— After years of inaction, at age 47 (a year ago) I had a painful episode that failed to stop after a couple hours so I went to an ER. They put all the sensors on you and make a big fuss. They inject something and say it will feel like a horse kicked you. But it doesn’t feel like anything (to a cyclist) … It seemed like the same feeling I would get when it abates on it’s own… there is a big heartbeat — like a “mega beat” that stops the superficial, fluttery, ineffectual and annoying tachycardia feeling. The big beat feels like a rush of relief and a very good feeling. In my unscientific way, my felt observation was that the electrical impulses coursing around right themselves … and that finally a gush of oxygen rich blood is getting pumped.

— After the ER visit, of course I was referred to a cardiologist. A very accomplished surgeon, Dr. Westby Fisher recommended the arthroscopic ablation surgery, but he said I could choose not to do it and instead go on without it with relatively no risk of any problem. He did say that my heart could eventually “wear out,” He did recommend I get this surgery. I believe he gave the following statistics regarding the procedure which weighed very heavily on me and still does — he said there was a 5 percent chance of death, a 20 percent chance I’d need a pacemaker, and also a pretty big chance they would not find the right ablation point. I think they had a general site in mind for where the ablation was going to happen and the risk lay in damage to tissue close to this critical point. I’m clearly not a doctor … I weighed all the years of having had this damned problem and did not do the surgery.

— Symptoms: I get very fast heartbeats up to 254 that I calculated with my HR monitor. Try as I might I could not trigger my symptoms when I was prescribed the big bulky take home hospital monitor thing. But when I went to the ER it was at 210. Way back I had HR monitors that would not register as high as my HR got and the HR monitor just went blank. I sometimes would feel feint and need to stop my cycling effort. I felt general weakness in my legs. During tachycardia you can see my heartbeat on my sternum, in my neck veins and it was apparent that my heart was going nuts, even to the naked eye. There was a certain mild angina accompanying the fluttery, but usually very fast rhythmic beating of what felt like the outer skein of my heart muscle itself, not just a vague feeling in the chest- rather, “hey, I can identify the perimeter of my heart in there… wow!” So the symptoms were freaky I guess, but now it’s de rigueur. Episodes typically last 45 minutes, but it could be 5 minutes or 1.5 hours. The beats generally are very fast like 230 bpm, and they do not gradually go slower and return to my normal 60 bpm resting HR. Instead, it is this tremendous, sudden return to normal with a big BABOOM corrective heartbeat, then… back to normal, all systems go… Symptoms also include pain in the neck, stiffness in the neck and torso. Pain down the arm. Of course, the scary pain down the left arm confirming to yourself that you are having a cardiac problem to help scare the shit out of you more.

— Onset: 90 percent of the time extreme physical efforts. For me, cycling sets it off. But here are my prevention secrets: regular training prevents episodes, as does generally better fitness levels (mine vary as I put on weight often in the off season). A good warm up is critical. Tachycardia is ALWAYS triggered by doing a very intense maximal effort, then sitting completely up and resting. When this happens, for example, guys in front of you sit up unexpectedly, or racing up to a stop light and not making it (if you’re a city rider like I am now) it feels like your very fast, well-trained heart immediately wants to rest and so your heart gets a breather and immediately tries to enter it’s well-deserved slow down, because you’re fit and you are able to recover like this as a cyclist. Especially the more sudden the stop, it feels as if electrical impulses kick in to tell your already racing (160-180+bpm) heart, “oh no you don’t,” you have to keep beating fast because what if this guy starts going hard like that again. So the prevention secret is… don’t sit up… if you do a TT effort, even really intense, and you just do not slow down, then you will be OK. So that’s how I need to ride, or literally my group ride is over. A million times on group rides I have been pulling and killing it at very high paces and then just gone to 7mph, goodbye.

— Problems- Beer the night before = increased risk. Any coffee = increased risk. Heat = increased risk. Burping triggers tachycardia.

— Dealing with it: After years of kind of figuring out this heart problem, I can finish a hard group ride during an episode, as long as it’s not over 25 mph (it’s all flat here). I can do 300 watts, but never 400 or any jumps with it. I can put it in the biggest gear and force my body to grind it and ignore the other symptoms. I use my respirations to help my blood circulate and keep my heart beating in an underlying way, while all the weak fluttery surface beats are figuring themselves out. Interesting the tachycardia episode ends when it wants to, regardless of whether I keep pushing on a long ride or not. So I can kill the first hour of a 60-mile group ride, get tachycardia for the middle 60 minutes and somehow suffer through that, then I can feel like a MILLION bucks and kill the last hour. Having the weird, very fast heart beats kind of makes me feel like I just never feel like I am tired really during riding and I think it kind of makes me stronger because I’m not suffering or concerned when my HR is at 186 from an actual effort.

— Outlook: This goes away when you don’t exercise, but not really. I can get tachycardia now when I’m sitting at the computer, and the old ticker just goes off sometimes. Sadly, as I get older I think it is happening more. Of course, I know I sound foolish. But I have to be honest — cycling is my complete and utter joy in life like no other, so I selfishly cling to it despite this condition (and other responsibilities more pressing and precious).

I learned that Bobby Julich has my kind of tachycardia and he got the surgery.

I think you are wise and properly careful (making me a little bit feel like I’ve been a fool for 28 years); however, my doctor really did say I could probably continue with no problem based on my history.

I think the heart is a very vibrant and smart creature that is trying to keep up with the hard work we cyclists (and other endurance athletes) inflict on it, and I think this problem is linked to intervals.
— Ted

Dear Lennard,
We had a brief discourse a year ago, after I was diagnosed with SVT. I’d like to update you on my condition.

I went in for an ablation on April 24 of [2015]. I was very, very scared, and thought about pulling out on several occasions leading up to the event. In the end, I made my peace with God and settled in for the ride. Lucky for me, I fit the “normal” statistical model and everything went wonderfully. As it turns out, my arrhythmia was actually WPW and could have killed me. I used Dr. Francis Gno, and the procedure was completed in a few short hours.

I never knew what a heart should feel like.

I rarely notice my heart these days, and I never think of it while exercising. While I certainly don’t go as hard as I used to, I still managed a fifth place in the Laramie Enduro this year. The year before I finished an hour slower. Occasionally, I catch myself doing something that used to cause a potential episode, and I marvel at how I feel so … normal.

For me, the ablation was a complete success. I still don’t go “all out” on the bike that often — I’m not sure if I ever will. The memory of an arrhythmia is slow to fade. I do, however, enjoy living my life not worrying about my heart. Not listening to every beat — not waking in the night after turning over wondering if these few skipped beats will lead to another episode.
— Drew

Dear Lennard,
I’m sure I’m not the first person to say this in response to your answer to Frank on 10/20, but the second paragraph… it is exactly what happened to me.

Crazy arrhythmia, ER, treadmill stress test, then angiogram. I now quote the doctor, “I wish I had your coronary arteries!” No shit, those were his exact words!

I’m 49 going on 50 and I’m super worried. I didn’t even really do any racing from 20s through 40s though — just started riding a little seriously in the last two years. Not even racing! Yet these arrhythmias are really freaking me out.

One thing I noticed is that for me (and we’re all different), alcohol really exacerbates it. I went no beer/no wine for two months, and the arrhythmias pretty much went away. Then turned alcohol back on with a little red wine with dinner a few nights a week, and pretty soon the arrhythmias were back. I’ve now cut alcohol out completely, and they haven’t returned. Maybe for me this is the answer.

Anyway, one last point. One reason for me I was in denial is that when I’m on the bike, hitting 180+ heart rate, crushing a climb, getting a new PR, I feel great! I think, “How can I have a heart problem?” It’s hard to square having a heart problem when the heart is not holding me back when I turn up the watts.

Also, it’s been helpful for me to check my HRV every morning. If it’s in the 5-6 range (either sympathetic or parasympathetic), I take it easy, but still ride. 5 and lower is right out! 7-10 means that if I’m otherwise ready (legs feel good, etc.) I can light it up.

Anyway, thanks for your great article!
— Jonathan

Dear Lennard,
Thanks for sharing your experience and very clear reflections on it. FYI, as you may know, Sean Yates in his book, “It’s All About the Bike,” writes about his similar experience. Lifelong rider, former pro. Heart problems later in life. See chapter 15.
— Walter

Dear Lennard,
I read your recent article in VeloNews about the aging heart of endurance athletes. While I didn’t cycle at your level, I raced both mountain (expert) and road bikes (Cat. 2) for over 25 years. I too experienced cardiac issues that were never explained. For instance, after a short hard effort (mile climb) my heart rate would begin a normal decrease from about 165 to under 100 in about a minute. Then, it would suddenly spike to almost 200! I kept records of this for years with a heart rate monitor and was examined in a cardiac lab several times. None of the cardiologists I saw could explain it. One said it was likely due to a sudden decrease in BP. I always suspected an electrical issue, similar to the ones you described. I quit cycling rather suddenly at 59 because of severe neck pain after just minutes on either bike.

Not only do I believe that years of training and competitive cycling has affected my heart, I am now experiencing a degenerating cervical spine. My neurosurgeon said I simple wore my neck out cycling. The odd neck position, constant vibration, and many crashes have worn my neck out. I have looked for research on this to no avail, but maybe you have an insight. Have you heard of other competitive cyclists developing spinal disease in later life?
— R.H.

Dear R.H.,
Yes, I have.
— Lennard

Dear Lennard,
Have you looked at your diet regarding heart arrhythmia? Reason I am suggesting is that several years ago I was drinking a lot of Gatorade and not exercising much when my heart started racing up and down. I concluded the electrolytes were interfering with the impulse signal to control my heartbeat and as soon as they were purged from my system, I was fine.

I also know that potassium can have the same effects on me and cause arrhythmia after eating a meal with foods high in potassium like spinach. Also, my mother recently had an arrhythmia issue when the doctor tested her with an EKG and was about to put in a pacemaker when I told her to wait a week and back off on the spinach, cantaloupe, and watermelon (high potassium foods). She is perfectly fine now. She also has backed off on taking vitamin supplements since she has been eating a lot more green, leafy vegetables than prior with her diet.

Hence, potassium can really mess up your system as well as electrolytes.

Anyway, just FYI, regarding what I know. The doctor didn’t even figure this out, I did! And I am not even a doctor. Scary how little doctors know about nutrition or foods/vitamins impacting normal heart rhythm.
— David

Dear David,
Yes; trying to figure out if things I’m ingesting are helpful or hurtful to my heart is a constant for me and seems to be for the majority of the people I know who have experienced exercise-related heart issues.
— Lennard

Dear Lennard,
Just read your article. I think you are on to something.

I am lying in a hospital bed here in the Mayo Clinic hospital post heart ablation for extreme Atrial Tachycardia (SVT or supra ventricular tachycardia).

At rest minus beta blockers, my heart rate was pre-ablation 180-190.

I have freaked out many cardiac nurses with this heart rate but EKG is always normal as was blood pressure and no chest pain. No history of heart issues in my family.

But wrestled in high school, then I was a runner until knee issues stopped that, then for the past eight years, I’ve done hard cycling. I took pride in beating the younger guys in the sprints! Even though my heart rate went to 220.

I had an errant initial trigger point just outside the sinus node which was ablated. Now resting heart rate is 80-85.

I am going to show your article to Dr. Kusumoto, my electrophysiology cardiologist, tomorrow when he discharges me.

I think maybe I should start riding with guys my age (I’m 66) and not push so hard. I have a 20-month-old and still need to practice dentistry for awhile.
— Jim

Dear Lennard,
You mentioned training 700 hours per year, is that a long-term average, or was that your peak years? I know one person who has similar issues and he was a pro cyclist, so I assume he also put in big hours. Have you heard any estimates on what level of training it takes to put yourself at risk for arrhythmia?
— Rob

Dear Rob,
700 hours of training was not uncommon for me. I think I had a run of almost 10 years where I cross-country skied over 100 days, year, with average duration being over two hours. Then figure in a lot of riding on the remaining 265 days in the year, and it gets to 700 hours easily.

No, I have never heard any cardiologist give an estimate of what level of training it takes to put yourself at risk for arrhythmia. I don’t expect to, either. It’s just not one of those questions that there is likely to be a universal answer to, at least not one where there is enough data for a cardiologist to say, “here is the line; don’t cross it.”
— Lennard

Dear Lennard,
I am a long-time fan of your column and highly respect your opinions on all things bicycles and training. However, after just reading your response to a question “the heart and masters cycling,” I am concerned about the inaccuracies in your response, and I want to provide some clarity if you’d allow.

I am a competitive cyclist and board certified cardiologist on staff at the University of Pennsylvania. This is a niche interest of mine and I regularly consult with patients on this very question.

By the way, the “Cycling to Extremes” article by Chris Case is breathtakingly well researched and on-target. Mr. Case should be commended for his work. I have referred patients to this for further reading.

The short answer to your reader’s question is that myocardial fibrosis is not a normal response to exercise. The Pheidippides myopathy that you mention is not normal, but in the minority of people who have Pheidippides, the resultant scarring can lead to an increased risk of ventricular arrhythmias and death. This is probably a heterogeneous condition, meaning that the cause and appearance is not uniform. In some it may be a mild version of a rare disease called “ARVD” but more often it’s probably due to underlying, “garden variety” coronary artery disease, which is very common. Many more people, however, have scar than have sudden death.

Atrial arrhythmias, especially atrial fibrillation, is entirely distinct from this. This is not an arrhythmia that predisposes to sudden death. Athletes are probably at higher risk for it for several reasons, but chief among them is left atrial enlargement. To simplify somewhat, heart chamber enlargement is an appropriate, physiologic adaptation to endurance exercise, but a larger left atrium is more apt to fibrillate and cause this chaotic heartbeat. The older you are, the more likely you are to have atrial fibrillation in general. Combine exercise and age, and masters athletes are likely going to have an increased risk of Afib compared to their otherwise healthy non-endurance athlete age-matched peers (but probably lower risk than their obese, hypertensive, diabetic peers). Afib can completely undermine aerobic performance and it predisposes to a higher risk of stroke. There are many treatments for it, however.

Finally, the biggest risk to the masters athlete is still probably good old coronary artery disease. Endurance athletes are not immune to coronary disease or plaque buildup in the heart’s own arteries. Genetics can certainly trump good habits.

This is a complicated question your reader asks and there is no way to address all the possibilities and nuances in a website question and answer column. I encourage masters athletes to have a conversation with their doctor about heart risk in general and especially as it pertains to training vs. the usual exercise most Americans do. I also urge readers to seek the opinion of a board certified cardiologist if uncertainty/questions remain.

Myocardial fibrosis and cardiomyopathy certainly overlap in a Venn diagram type of way. Cardiomyopathy specifically indicates a dysfunction and/or structural abnormality of the cardiac muscle. Myocardial fibrosis is a more specific term (used either with microscopy or sophisticated imaging techniques like MRI), which indicates replacement of cardiac muscle cells by collagen or scar tissue. You can have a cardiomyopathy without fibrosis. You can have fibrosis on a small scale at least without cardiomyopathy.

I think a lot of the confusion about exercise and its effects on cardiomyopathy, myocardial fibrosis, and sudden death comes from the fact that this is not a homogenous population or process. You have the extreme athletes like the one in the study that you mention and then you have the typical weekend warrior. There are many more weekend warriors or working cat 4s/Masters than there are ultramarathoners.

I would caution generalizing the findings of retrospective studies of niche populations with small sample size is to a more general population. I think one of the dangers especially in the lay press is scaring people away from exercise. There is a very clear benefit of non-extreme exercise in reduction of “bread and butter” cardiovascular disease (lower MI, stroke, diabetes, etc.).

In some people (and not everyone it seems), higher volumes of exercise seem to increase risk of arrhythmias and sudden death. The effect is probably small and there is probably a dose-response effect. But again, this is heterogeneity. It seems that cyclists may be at lower risk for sudden death compared with runners/triathletes. There are theories as to why, but they’re just theories. And then there’s data about retired professional cyclists living longer than the general population, so again, this effect is not found in everyone it seems. And I’ll point out that fibrosis by MRI certainly exists without sudden death.

It’s a fascinating area and poorly understood. It’s unlikely to be clarified soon. I’m gonna keep riding my bike, watching my weight and racing ’cross because I feel better when I do. I wish my patients could find something they have as much fun doing that keeps their weight and fitness at a good level.
— Carl

Editor’s note: Lennard Zinn is not a medical professional, and this article should not be construed as medical advice.