Is Running Fast Hard on Your Heart Health?

June 16, 2012

The popular press weighed in this week on the timely controversy about the cardio-health benefits of exercise – think running. Does exercise provide cardio-protection or as the new provocative research reports(1) suggest that in some 10% of the participant exercise increases the risk factors of heart health more than it helps to reduce them.

I asked three different authorities and runners to weigh in to answer the question “Is running fast hard on your heart health?” Their responses below come from three different perspective – the scientist, the medical doctor, and the veteran ultramarathoner.

(1) From medical doc and ultra-marathon researcher, Martin Hoffman, MD*
“I don’t think the “body stress”2 is a cardiac stress. It can certainly stress the kidneys though. The prolonged low-intensity probably fatigues the heart (as for skeletal muscle) which is what our studies have shown. My thought is that the low intensity exercise, even if prolonged, is likely to be cardio-protective. But we don’t know with certainty.

I basically agree with Carl Foster, Ph. D. (see below) that probably the high intensity stuff has the most likely serious long-term consequences, and the data are clear that high intensity exercise is associated with a higher risk of acute cardiac event. While that risk is higher during the exercise, the overall risk of cardiac event from regular exercise is lower than if one didn’t exercise.

One question that hasn’t been answered is “what is high intensity?” I would argue that the way I used to run (whether it was a 5K or a marathon) was high intensity, but I’ve never run 50+ miles (perhaps even 50K) at a high intensity. The longer the distance, the lower the intensity has to be. So perhaps marathon running can cause some cardiac damage if you are racing, but perhaps a 100 mile won’t because even the best runner must be at a lower intensity. So far, our studies of ultrarunners only show transient dysfunction as would be expected from a tired muscle, and as far as I know, the credible work showing long-term cardiac issues have been in “marathon” runners.

I’m off to run my tenth 100 mile ultra this weekend so that should tell you how much I am worried about cardiac consequences of exercise.

Marty Hoffman, MD, Chief of PM&R, Veteran’s Administration, Northern California Health Care System

(2) From 30-year running advocate and ultra-marathoner Bob “Diesel” Crowley
My experience is some of this “body stress” must translate into incremental heart stress due to the trauma. I average during marathons running moderately at a 75% of maximum heart rate pace during marathons, 70% of max for a 50 mile ultra, and 60-65% of max HR for a 100 mile race. So as the distance goes up the high intensity goes down putting the heart under less stress but the muscles, joints and tendons under more stress. As distance goes up, I accommodate the trauma with decrease in intensity. My guess is that this accommodation might reduce the risks of cardiac events during running.

University professor and skater Carl Foster, Ph. D. co-author of BE A BETTER RUNNER
There has been evidence for many years associating very heavy exercise with a variety of cardiac conditions.  From my standpoint, the basic answer is that racing isn’t good for you.  If you believe Loren Cordain’s work, beyond his paleo-diet (which I know Sally Edwards, my co-author doesn’t concur but in my opinion is the best answer out there relative to nutrition), humans evolved as hunter-gatherers. This means that our ancestors spent a long time at relatively modest efforts, and then brief periods at very high efforts.  What we probably didn’t do was go long periods at relatively hard effort, so we didn’t evolve bodies well designed for that kind of activity.  Mother Nature didn’t anticipate the evolution of sport (a surrogate for hunting and for warfare).  In terms of the concepts you talk about, the high zones have their risk.  High intensity exercise, while very effective, is also somewhat more dangerous.

The basic epidemiologic evidence also suggests that active people are much healthier than inactive people, but while they are active they are at an increased risk of cardiovascular events, although still lower than when inactive people exercise.  If you have underlying cardiovascular disease, which most people beyond their 20′s do, there is a certain risk of heavy exercise, particularly when inactive people are beginning exercise programs. Sally and I have had healthy discussions, well positive arguments, about high zone training in relatively untrained individuals.  Although it adds interest, it definitely adds risk.

From Sally: Just to provide my perspective on the answer to the title of this article and question: Is Running Fast Hard on Your Heart Health? The answer is – it depends.

Sally Edwards, Founder and Developer of HZT, the Heart Zones Training – Max and Threshold patented training systems.


*Martin D. Hoffman, MD, FACSM
Marty is the Chief of PM&R, VA in the Northern California Health Care System. He is the Professor of PM&R, University of California – Davis. He currently works for the Department of Veterans Affairs in the Nor Cal Health Care System with the University of California Davis Medical Center, Sacramento, CA. He is the principal researcher publishing his results of runner participation in races like the Western States 100 Miler.

** Bob Crowley, Founder, Trail Animals Running Club
Bob was a late bloomer, running his first 10K in 1987at age 30 and his first marathon a year later. A proud husband and father of two sons, Bob affectionately nicknamed “Diesel” has since successfully run in over 60 ultras (50 Kilometer to 100 Mile events), continuing to run some of his best times at various distances into his 40s. A Villanova University graduate and veteran CEO in the high-tech sector, Bob’s experience and passion have driven him to found the Boston, MA based running club: Trail Animals Running Club.

***Carl Foster, Ph.D., FACSM
Carl is a researcher and professor of exercise science at the University of Wisconsin-La Crosse in the Department of Exercise and Sport Science. He has published over 300 peer reviewed original research articles, co-authored Be a Better Runner, and is a fitness runner. He is considered by many as one of the best applied exercise physiologists in the world and was elected to be the President of the American College of Sports Medicine in 2005.

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