When it comes to exercise, it is possible to get too much of a good thing. Regular participation in appropriate mild to moderate exercise is one of the most important habits for optimal health. The kind of detrimental excess endurance exercise I’m going to implicate includes marathon distance running, 100-mile bike rides, Iron Man/Half Iron Man triathlons, and other flat-out, pedal-to-the-metal exertions for more than an hour. Regrettably, I confess: “Been there, done that!”
Hyper-exercisers tend to be Type-A-driven individuals. This fits the profile of many of us in medicine. In case you haven’t got the moderation message, especially those of you over 40 and running more than an hour, I’m going to share my experience. I’ll include some of the research my cardiologist James O’Keefe, MD, and others have published over the past 15 years. This discourse is a personal perspective, not a scientific paper; thus, I will be using only a single reference. Relevant scientific papers can be found at this link: Missouri Medicine.
“Marathons in the Long Run Not Heart Healthy” was published in Missouri Medicine in the March/April 2014 issue just prior to the Boston Marathon. That issue elicited a significant outcry from the hyper-exercising marathon crowd. ‘Outcry’ perhaps does not do justice to the noise; it was an angry roar. What our detractors then labeled as mistaken and misleading has subsequently been proven by many published studies to be the real deal. These confirmatory studies come up easily with literature searches. Google pulled up 18,700,000 hits in 0.36 seconds for “marathons are unhealthy.”
Being of a certain age, I have seen many medical putative ‘facts’ turn into fiction. In spite of what the dogmatic Dr. Fauci says, sometimes, if you “follow the science,” it will take you over a cliff.
Here are a few select discredited shibboleths: in the 1950s smoking was good for chronic cough, calming the nerves, caused no health problems—certainly not cancer—and was a harmless makes-me-look-cool pastime; coffee caused heart attacks and ulcers, sugar was harmless, and recently shutting down schools during COVID is good science. Well, you get the idea.
My grandparents’ and my parents’ physicians felt that rest, indeed absolute rest, cured many illnesses. Doctors ordered patients “to take to their beds” for heart disease, especially after a heart attack, after childbirth, and after surgery. Vigorous activities such as walking, running, or swimming were considered dangerous. During my youth (yes, I was young once) men in their 40s had epidemic-like sudden deaths from heart attacks and other cardiovascular disease. These deaths were often erroneously attributed to exercising too much or working too hard. These were “take it easy” times.
The “exercise is bad” mantra began to fade with the seminal studies of Scottish cardiologist Jeremiah Morris, MD. The London Transport Workers Study (1948-1952) compared inactive bus drivers who sat their whole shift versus the conductors who spent their shift on their feet walking, often climbing stairs on two-deck buses. The sedentary drivers had a higher incidence of cardiovascular disease.
The second giant in this field was American cardiologist Jeremiah Stamler, MD, an active exerciser who was productive until his death at age 102. The Father of Preventive Cardiology, Dr. Stamler, introduced the concept of cardiovascular risk factors in the 1970s. These have subsequently been modified to include physical inactivity.
The third giant in the exercise as medicine movement is Kenneth Cooper, MD; he is now age 92, has run over 40,000 miles, and is actively engaged in preventive cardiology. In 1969, Cooper published the book Aerobics, which explained the benefit of regular mild to moderate exercise to the general public and quantitated healthy exercising. I read most of the important Morris, Stamler, and Cooper papers. I was beyond impressed. Exercise, something I had done mainly through sports since childhood, became my lodestar to staying healthy. The more exercise I do, the healthier I will get, or so I erroneously thought.
I began long-distance running in 1967 while a medical student at Loyola University Stritch School of Medicine. I would rarely run for less than an hour and did so with the expectation that I was building a robust cardiovascular system. An international movement of “exercise is good for you; do as much as possible” developed. Among the movement’s high priests was pathologist Tom Bassler, MD. Dr. Bassler was an esteemed poo-bah in the American Medical Joggers Association, of which I was a charter member. “The Bassler Hypothesis,” long since disproved like the flat earth theory, was that running a marathon imparted absolute immunity from coronary artery disease. Running events proliferated: 5K, 10K, half and full marathons, outlandishly difficult races like the Leadville (Colorado) 100 Mile Challenge run at an altitude of 10,158 feet. At the apex of hyper-exercise idiocy is the Self-Transcendence 3100 Mile Race. Since its inception in 1996, only 53 deranged runners have completed the entire course. How difficult is it? More than 4,000 people have climbed Mount Everest to the summit.
As an ophthalmology resident at Emory University, my first published paper of the some 225 that I have written was “The Doctor as a Coronary Candidate: Survival of the Fittest.” Published in the August 1974 Resident & Staff Physician, I urged doctors to run as far as fast as they could. Mea culpa!
Moving to Kansas City in 1975, I ran more than 30 Hospital Hill Half-Marathons, three full 26.1-mile marathons, a half dozen Baptist Hospital Triathlons, and two Half-Ironman Triathlons held at Smithville Lake. The latter was a 1.2-mile swim (my weakest event—I was usually last out of the water), a 56-mile bike ride, and a 13.1-mile run. Like many runners of that era, I often managed gratuitously to work into conversations that I was a marathon runner. When it came to talking about exercise, I was insufferable. Another mea culpa.
All was going well until age 60. While taking a shower, I felt my heart beating very rapidly. I took my pulse and found it irregularly irregular. Atrial fibrillation (AF)? How can this be? My running was supposed to make me invulnerable. A trip to North Kansas City Hospital and an extensive cardiac workup was done and normal except for the AF. Converted back to normal sinus rhythm, I started doing research and found that “lone atrial fibrillation,” AF in an otherwise normal heart was common in long-distance runners and cyclists. This was news to my former cardiologists. Undeterred, I continued to run for hours on end (six hours is my record).
I began to read in Runner’s World of marathoners dying while running, having abnormal coronary artery angiograms, and needing heart artery bypass surgery. Among the suggestions I saw several times was to have a CT coronary artery calcium score (CACS). Calcium is a surrogate for coronary artery atherosclerotic plaque burden. I asked my erstwhile cardiologist about taking that test. I was told it would not provide any useful information and was expensive. Being a compliant patient, I uncomfortably accepted.
Fortuitously, my insurance changed, and I needed to find a new cardiologist. I knew of James O’Keefe, MD, by reputation. I was extremely impressed by his emphasis on preventing cardiovascular disease. During my initial evaluation, I asked about a CT CACS. He readily agreed, and the test was easy to schedule and inexpensive. A normal CACS is zero, and less than 100 is usually non-concerning. At home, about three hours after taking the test, I got a call from Dr. O’Keefe’s office. Would I have my wife drive me now directly to his office? My CACS was 1606. Another even more thorough cardiac workup was done.
The primary abnormality was the sky-high CACS indicating coronary artery disease. I was put on statins.
“So why do I have more calcium in my heart than the water pipes of a 100-year-old house?” I asked. Dr. O’Keefe indicated it was becoming evident as a complication of excess endurance exercising, especially after age 40. Missouri Medicine, the medical journal I have edited for 23 years, received a manuscript from researchers in Minnesota that reported increased coronary artery calcium in older runners compared with matched non-runners. I intentionally scheduled this peer-reviewed paper to be published just prior to the 2014 Boston Marathon. The startling research was picked up by the national press and international running community. The response was bi-modal. The first: “Good to know, I’m cutting back on my mileage and intensity level.” The second: “Something is wrong with your studies; I’m not cutting my mileage.”
An internationally known marathoning cardiologist from Harvard (that used to mean something) called and read me the riot act. How could a medical journal from “fly-over” country make that outlandish claim? How times change. That same cardiologist wrote in the February 11, 2024, Kansas City Star that he had given up long-distance running and advised his patients to do the same. Graciously, he acknowledged that Missouri Medicine was among the very first medical journals to report elevated CACS in long-distance runners.
There is some good news for those of us who cannot undo decades of excessive endurance exercise. There is a notable histological difference in the morphology of the coronary artery plaque in hyper-exercisers and the more usual non-exercising patients with multiple risk factors for cardiovascular disease. The risk of a cardiac event varies between these two groups, even for the same CACS, being lower in runners like me. The exercise-induced atheromas are low-lying, fibrotic, and have less lipid. The high-risk CV patient has elevated, lumen-occluding, large, thrombotic-prone lipid plaques. This type of atheroma is more prone to cause sudden coronary artery occlusion. Nevertheless, a CACS of zero and no atheroma would be a happier story. As a reminder of my hyper-exercising past, I am in constant AF and on Eliquis. My treadmill stress test for my age group puts me in the top 99 percentile for the longest time to exhaustion. I’m still insufferable talking about exercise.
So, what is the takeaway here? First, do not conclude that exercise is dangerous. I disabused you of that in the first paragraph. But like the medicines we prescribe, it is important to get the dosage correct. I had hoped to get through this article without a reference, but I find this one essential. Dr. O’Keefe and colleagues have quantitated guidelines for optimal exercise. They call that exercise sweet spot “The Goldilocks Zone.”
How do I exercise now? Walking, gardening, and most importantly, swimming three times per week for about an hour. For the endurance athletes among us, recall the words of Dr. Cooper, “If you run more than 15 miles a week, it’s for something other than aerobic fitness.”
As the Greek poet Hesiod said in 700 BC: “All things in moderation.” Amen to that! Or as John Hagan, upon realizing years of running marathons are unhealthy: “My feet are killing me.”
John C. Hagan III is an ophthalmologist.
