Is there such a thing as too much exercise?

One question that we get asked frequently at Wisconsin Cardiology Associates is “How much should I exercise?”.

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Research has shown for decades that physical activity and exercise training are associated with a lower risk for heart attacks. In contrast, insufficient physical activity is responsible for 12% of cardiovascular disease mortality.

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And there is evidence that you don’t have to be a “gym rat” to earn this benefit. Only 15 minutes of physical activity per day is associated with a 14% reduction in all‐cause mortality! In fact, exercise improved overall survival in a dose-dependent fashion up to about 60 minutes of daily vigorous physical activity.

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Curiously, in recent years, some studies have shown that middle-aged and older male athletes who exercise frequently to a very high intensity level had increased coronary artery calcification, atherosclerotic plaques, and atrial fibrillation.

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So is there such a thing as too much exercise?

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In 2008, a researcher named Möhlenkamp studied 108 male marathon runners and compared them to 216 control subjects in a research study called the “Heinz‐Nixdorf Recall” study. They found that the German marathon runners had higher calcium scores compared to the controls, when matched for both age and risk factors.

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Similarly, in 2017, another researcher found that among 284 Dutch male athletes, the most active athletes more often had coronary artery calcium compared with the least active athletes. Interestingly, 73% of the plaques or blockages in the athletes’ hearts were calcified or “hard” plaques instead of “mixed” plaques (only 23% were a mix of soft AND calcified), whereas control subjects had fewer calcified plaques (31%) and more mixed plaques (62% of plaques). Because calcified or “hard” plaques are associated with a lower cardiovascular risk than mixed plaques, these findings suggest that even though high level athletes have more hardened plaque, they have a “safer” plaque composition than non-athletes. 

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But it’s not just plaque and blockages that we have to worry about. Almost all studies have observed a higher rate of Atrial Fibrillation amongst endurance athletes as compared with non-athletic individuals. Interestingly, this excess in atrial fibrillation has not been observed in female athletes (and the difference between genders is not simply explained by the lower proportional representation of females in endurance sports).

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The relationship between exercise training characteristics (intensity and duration) and coronary atherosclerosis has been evaluated, too. While vigorous intensity exercise was associated with a smaller increase in Calcium Score, very vigorous intensity exercise was associated with a greater increase in Calcium Score and an increased development of calcified plaques. The frequency and duration of exercise, on the other hand, was not associated with changes in coronary calcification or plaque. Importantly, in this study, while very vigorous activity was associated with prevalent CAC, it was not associated with increased mortality after a decade of follow-up, even in the presence of clinically significant coronary calcium levels.

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Running speeds of 6-7 miles/hour, running distances of about 1-20 miles/week, and frequencies of runs of 2-5 days/week were associated with lower rates of all-cause mortality. Higher weekly mileage, faster running paces, and more frequent runs diminished some of the survival benefits. 

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What does all of this tell us?

The research is very clear: the health benefits in going from unfit/sedentary to intermediate fitness are significant, and much greater than from going from intermediate fitness to extremely high fitness.  Doing up to 60 minutes each day of vigorous physical activity improved overall survival, but beyond that there are diminishing returns.

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At Wisconsin Cardiology Associates, we recommend 30 mins of moderate intensity exercise 5-7 days/week. Can’t do that right away? No problem. Start with even just 10 minutes a day of something. We know that it is better than nothing at all. 

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Come join us!

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2023 SE Wisconsin Heart & Stroke Walk 

Saturday, September 23, 2023

Veterans Park Milwaukee’s Lakefront

1300 North Lincoln Memorial Drive | Milwaukee, WI 53202

Booth Open 9:00am

Walk Begins 10:00am

Find the WCA tent for some fun giveaways, and we will donate an additional $25 for every walker who joins us.

CLICK HERE TO JOIN OUR TEAM!  https://www2.heart.org/site/TR/HeartWalk/MWA-MidWestAffiliate?team_id=801478&pg=team&fr_id=8976 

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Aengevaeren VL, et al. Circulation. 2023, Volume 147, Issue 13: 993–1003

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Wen CP, et al. Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study. Lancet. 2011;378:1244‐1253.

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Möhlenkamp S et al. Running: the risk of coronary events: prevalence and prognostic relevance of coronary atherosclerosis in marathon runners. Eur Heart J 2008;29:1903‐1910.

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Merghani A, et al. Prevalence of subclinical coronary artery disease in masters endurance athletes with a low atherosclerotic risk profile. Circulation. 2017;136:126‐137.

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Aengevaeren VL, et al. Relationship between lifelong exercise volume and coronary atherosclerosis in athletes.Circulation. 2017; 136:138–148

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Lee DC, et al. Running and all-cause mortality risk - is more better? Medicine & Science in Sports & Exercise. 2012;44(5):S699

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Photo by Josh Gordon

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