Endurance Exercise, Cardio, and Heart Damage - Update

(Bob ) #1

I tried to start a conversation in the cycling forum to talk about the effects of chronic cardio on heart problems, particularly Afib, atrial fibrillation. No one had anything additional to contribute.

In the last week, I’ve been reading this book:

If you’ll pardon the pun, I heartily recommend it to anyone with concerns.

Co-written by this MD, Dr. John Mandrola.

Dr. Mandrola is a competitive cyclist (or has been) as well as a cardiologist and specialist in cardiac electrophysiology. He’s the guy who shoves tubes into your heart and burns dead spots into it to stop arrhythmias.

Briefest brief summary. Yes, chronically overstressing your heart can damage it. Yes, too much cardio can cause Afib and more serious problems. Yes, some exercise has been conclusively proven to be good for your heart. The problem is in finding and living in that “Goldilocks zone”: not too little, not too much.

(KetoQ) #2

A few years ago I had an afib episode during a coronary stress test. It hasn’t been a problem since. I mean, I’m still here.

Remember how cautious I felt about stressful exercise after my heart attack, but my doctor told me to go as hard as I felt comfortable going. At times when I had to run to get my train, I did feel short of breath.

However, since I have lost weight on low carb eating, this past Saturday I ran for 10 minutes at a 4 mile pace, which is very encouraging. I haven’t run like that in years.

Will say that low carb, along with a lot of the other physical activity I have been doing, appears to have hugely improved my cardiovascular health. No chest pain, shortness of breath.

Used to be a track and cross country runner in high school. I’m more concerned what lots of cardio, such as running, will do to my knees, which is why I prefer biking and weight training.

Do think about the effects of HIIT training on my heart. But it appears HIIT has been improving my cardiovascular fitness. As long as I don’t go overboard with it.

(Bob ) #3

I had an episode the day after my birthday when I turned 60 in 2014. I had never had sensations like that, and (very thankfully) haven’t had them since. I eventually saw a cardiologist to wear a Holter monitor overnight and was told I had Afib. They also said the monitor showed all sorts of rhythm problems. Compared to other symptoms and descriptions of Afib I’ve read, I don’t think I had that. They put me on a beta blocker and an aspirin a day.

They did a “nuclear stress test” (I love that name!) and an echocardiogram. Both said I had a normal looking heart. 2-1/2 years later I had emergency gall bladder surgery and supposedly my heart did something funky. The discharge papers said, “see your cardiologist! Right now!!” My cardiologist looked at the paper and muttered, “why do they send me :poop: like this?”. So he repeated the nuclear stress test and echocardiogram. Again, both said I had normal looking heart.

In the nearly 5 years since my first incident, I’ve only had what I thought were arrhythmia episodes a few times, The most recent was last February or March. Strangely, every time has been in the early morning hours and went away in half an hour or maybe an hour. The cardiologist says if I get short of breath, or chest pain, or any of the serious symptoms to get to the ER, but otherwise says there’s nothing to do.

I had stopped riding not long before that, but have been slowly getting back to it over the last month or so. Probably naturally, I’ve been concerned about making it worse. I’m deliberately taking it easier than I used to. I will be stretching out my ride times in the coming months, with a loose goal of wanting to “ride my age” in miles in February when I turn 65. I don’t intend to push high heart rates, which was always easy for me.

In the last few years, I’ve lost 60 pounds on keto and I’m hoping the fasting and autophagy are helping to clean out any wayward cells in my heart.

(KetoQ) #4

Good luck and be well.


Bob, similar situation here. I’m 68 and 15 years ago I had a nasty heart attack that only did minor to medium damage because I got to hospital immediately.

But it left me with “sick sinus syndrome” which means I have a short history of Afib (under control with beta blocker and aspirin), and have bradycardia (slow heart rate 45-50 resting), and have regular bouts of PVCs (premature ventricular contractions or skipped beats) which can really be annoying when you have a slow heart rate. The PVCs tend to be seasonal, such as around the equinoxes like now.

My cardiologist, who is big on low carb and fasting, says I’m not ready for a pacemaker and he’s not keen on ablation. My heart ejection fractions are still at a near-normal 50 percent. So he wants me to lose weight (have lost 37 lbs in six months on LCHF and fasting) and stick to walking regularly. I can still do vigorous cardio but he says to take it easy and cautious. Walking is good enough and my dog loves it.

And, yes, they cut my gall bladder out a few years ago (full open surgery) and my PVCs kicked in while the ER prior to surgery. It was nasty until they hit me with dilaudid.

Oh, and, yeah I had a total knee replacement 7 years ago and have suffered through 43 kidney stones. (The mountains of Vietnam and Agent Orange exposure we’re not kind to me.)

So, all said, my exercise regimen is limited but lo-carb and fasting have helped greatly. Sticking with ketogenic type eating should buy me plenty of time for medicine to patch me back together.

How I am not diabetic is a bit of a miracle. Whacked metabolism is a given but fasting BG is now down to mid-upper 80s with ketones at .5. I don’t go full Keto because of the really high fat requirements.

I could go on forever but this type of eating has been successful and encouraging as the weight falls off. Started at 255 on April 8, now 219. Only 20-25 pounds to go.

(Bob ) #6

Hi, Ben. There’s a very strong similarity between our cases, although you’ve been through more of a wringer than I have.

The first time I had the symptoms back in '14, I was in the men’s room at work. I felt like I had been punched hard in the chest. I took my pulse and it was 34. I’ve always heard or read that Afib felt like your pulse is racing, not bradycardia.

The way my MTFN (middle of the night ) episodes feel is like I have two separate pulse rates going. On one of those episodes, I checked my pulse on one of those pulse oximeters and I could see it get slower and faster (I’m a gadget freak - couldn’t resist picking one up for a couple of bucks on Prime Day a month after my gall bladder surgery). I don’t recall it going as low as it did that one time.

Right now, on a normal morning, after 2 mugs of coffee, my pulse is around 58 or 60 and steady.

I started going keto to prevent diabetes. My mom had it and my brother does now. I had an A1c done about 10 years ago that came back at 5.8. “Pre-diabetic”. Just had it checked in August and it’s 4.8. I’ve dropped around 60 pounds since that episode in '14. My cardiologist has never talked about diet in any way. Never said to eat low fat, keto or anything. He did tell me to lose weight, but that was 60 pounds ago, so not an outrageous suggestion.

One of the messages out of that book is that the repetitive stress of always pushing yourself to go faster and pushing well beyond being comfortable is the cause of heart trouble in athletes. With a goal of riding my age by February, it means adding 15 miles/month. On one hand, it doesn’t seem like that much, but I also need to work that message of reducing the stress deep into my head. I don’t want to make this worse by effectively saying, “I’m going to ride 65 miles on my birthday no matter what! If it kills me!”.

Back when I was more of a runner (like many cyclists, I switched because my knees were bothering me after years of running) there was a Tee shirt that said, “Joggers jog for their health. Runners run if it will kill them” and that machismo is probably what causes the athletic heart syndrome.


My heart problems began on two fronts — my own doing (eating high carb for decades) and my Vietnam experience (significant PTSD and Agent Orange exposure.

My family history and poor eating habits were aggravated by drinking out of, bathing in and swimming in dioxin-laced streams, not to mention sleeping on the ground of defoliated forests for months on in. It has been found that dioxin (a prime ingredient in Agent Orange) is linked to ischemic heart disease. It can also cause Type 2 D and numerous other cancers and neurological disorders. I can’t believe my 43 kidney stones are not Agent Orange related.

By the way, dioxin affects the DNA and most of the damage was done to our systems in the first few decades and symptoms did not appear until our 50s or so.

Add to that the fact that PTSD can lead to overeating because it is a coping strategy.

Enough with reasons and excuses, my Afib was several bouts of wild palpitations into 120+ range usually normalizing and subsiding suddenly within an hour. Very disconcerting. However, fortunately, beta blockers, aspirin and an anti arrhythmia med has calmed that problem leading to my bradycardia. Sitting and relaxing I stay around 45-50. Walking around the house and yard I respond well and reach the 70s and 80s. While walking my dog, 80s and 90s are attainable.

But it is when the skipped beats join the 40s is when it gets distracting. Cardiologist says as long as I’m not fainting (I do get light headed on Keto) and my ejection fractions remain strong I’m ok. He just wants me at or below 200 pounds but I want to get to 180 or less. (Started at 255 on April 8, now at 219).

So losing weight is imperative, not just a wish. Eating low carb (under 20-25) with IF (22/2 and 36/2) and some 3-day EF has been most successful and I intend to continue like this. I also briskly walk my dog 2 mi/day, 4 days a week.

Full Keto for so many of you is great. I just don’t think my body can tolerate it but it surely is a great guide and teacher.

(Tamela Robinette) #9

This is all very interesting to me. I’ve been a hard core runner for years and have done a ton of damage to my body with this mindset that I must go further and I must go faster. Last year I started feeling really run down, no energy, couldn’t think, couldn’t function. After a week or so of feeling that way I went to the doctor. He listened to my heart and checked my heartrate and immediately sent me to a cardiologist. My heartrate was in the 30s! I had no clue! The cardiologist did all the tests they do and told me I had “athlete’s heart.” Basically my heart was enlarged from all the stress I was putting on it running. I am 47 years old for reference. I took some days off but went right back to my usual running routine and did not give it much thought, but I have been seeing a lot information lately about the damage endurance athletes are doing to their hearts. I only run half marathons! That being said, I have developed chronic tendonitis in my right foot and after my last race, which was in early April, it flared up again and I’ve been unable to run. I have dialed back my miles in the last year due to the tendonitis and my resting heartrate has settled in the low 50s range. I’ve picked up weightlifting and have fallen in love with it. I have only been running on the treadmill at a very slow pace for one to two miles a day just to get some cardio in. I have decided with much agonizing to give up my halves. My body just can’t handle them. I am happy that I read this thread. It confirms the little nagging thought I’d been having that I could be doing permanent damage to my heart by pushing so hard. From now on I will only do 5k’s or 10’ks.

P/S my father served in Vietnam and has hypoglycemia, liver issues and lots of mental health issues. The doctors say his hypo and liver issues are definitely related to agent orange.

(Bob ) #10

Very interesting, Tamela. Still a subject I try to keep on top of.

My arrhythmia bouts are either very intermittent or I just don’t feel them (ignoring the little flutter feelings of PVCs which I get a few times a year). I’ve had none of the problems that wake me up in the middle of the night or bad feelings in over a year, now.

As strange as it sounds, it seems like the root cause is really being pushing too hard, being unwilling to quit. We all seem to feel we push through the bad feelings.

I’m back to riding three or four times a week and I make myself take it easy. If it’s a nasty day, I don’t make myself go out, like I did in my 40s. I don’t train hard every time, more interval than sustained. I’ve also started weightlifting again (we have a Bowflex), although I can’t say I love it like you say.

I do recommend reading the Haywire Heart if you’re interested, though. Scary in places, but still worthwhile.

(Tamela Robinette) #11

I certainly will! Added it to my reading list.


I am a retired professional runner, and was given “The Haywire Heart” by my my cardiologist (who is also a runner). When I went keto a year and a half ago, many of my chronic “running” conditions - inflammation, constant hunger, slightly elevated BP (for no reason), etc. - went away. But, I have to say, my other “off” conditions such as elevated pulse and high TSH (indicative of a thyroid problem) did not normalize until I stopped training hard. I’d had a few isolated bouts of "wonky heart rhythm (not sure if it was Afib), but have not had any since I moderated my training.

All this to say, I think heavy, prolonged training is hard on the ENTIRE system - cardiovascular, muscular, skeletal, and endocrine.

*my endocrinologist was amazed that my TSH dropped to normal AFTER middle age, as that is rarely the norm for women

(Tamela Robinette) #13

Agreed! I have 7 inch screws in my hip and permanent nerve damage in my foot and who knows what else will pop up. Hopefully nothing since I have become acutely aware of the damage I was doing to my body.