• Dr. Todd Hurst, MD

Can You Exercise Too Much?

Recently there has been a lot of media attention around the question of whether long term endurance athletic activity – like participating in marathons, triathlons, Iron Man competitions - can actually lead to a higher risk of heart disease.

In this video, I am going to answer the questions:


1. Is there such a thing as too much exercise?

2. What are the health risk of competing in an endurance athletic event?

3. Is atrial fibrillation more common in endurance athletes?


The first point I want to make is that the biggest problem in healthcare is not that people are exercising too much. Many people’s health is suffering because they are sedentary. For the most common health problems in our country like diabetes, high blood pressure, obesity and several others, the most effective treatment is more physical activity.


But the idea that if a little exercise is good for you, then a lot is going to be even better is almost certainly wrong. There is a point where too much is, well too much, even for things essential for life, such as oxygen, water or food.


Research as shown us that the relationship between physical activity and health looks more like this. As exercise intensity and duration increases, we see that the health benefits tend to become less. Most of the health benefits for physical activity happen early on just by getting up off the couch. However, the question is, is there a point where increasing amounts of physical activity can actually lead to worse health?


This is not a new question. In fact, legend has it that the very first runner of a marathon, Pheidippides, died after running from Marathon to Athens to announce victory over the Persians.


Risk of Participating in Endurance Events

And we know that participating in endurance athletic events does have a small risk of death. This recent paper looked at 31 years of triathlons and found there were 135 deaths among the almost 5 million participants.


· 47 years of age, 85% male

· Overall, 1.74 deaths per 100,000 participants

· Over 60 years of age - 18.6 deaths per 100,000 participants


Risk of Atrial Fibrillation

Long term athletic activity can also increase the risk of developing the heart rhythm problem called atrial fibrillation. Atrial fibrillation is the most common heart rhythm problem cardiologists see and it’s increasing at epidemic levels. Most atrial fibrillation is attributed to issues like high blood pressure, increasing age, obesity and sedentary lifestyle, but interestingly, long term endurance athletic activity also increases the risk of atrial fibrillation by about 2-10 times. A recent article suggested there is a threshold of about 2,000 hours of intense training needed to increase the risk of atrial fibrillation


Some interesting facts about exercise and the risk for atrial fibrillation:

· Intense exercise increases the risk in men but lowers the risk in women

· Moderate exercise reduces the risk of AF in men and women

· Some studies show a marked reduction in AF after abstinence from exercise


Back to our original question, is there such a thing as too much exercise? I thought about this question when I read an article in the New York Times about a race called the Quintuple Anvil Triathlon where participants run an Ironman length race every day for 5 consecutive days. While I admire the fortitude of these people, it does make me wonder if that is “too much” exercise.


Because my opinion is that there is a point where more exercise leads to worse health, even though there is not good research that proves this. The problem is, I don’t think we are ever going to be able to identify what that point is, because it is likely different for each of us.


And the last point I will make is that while there may be a health risk to intense exercise, that risk is likely small and you also have to weigh that against the benefits.

When I talk to my endurance athlete patients about the benefits of participating and competing in these athletic events, they often talk about benefits like a sense of purpose, accomplishment, comraderie and stress relief more so than health.


And I think that is reflected nicely in this quote from the New York Times article by a urologist who completed the Quintuple Anvil Marathon, “I know this is not good for my body, but it is good for my soul.”


And the beat goes on,

R. Todd Hurst, MD, FACC, FASE


R. Todd Hurst, MD,FACC, FASE

Center Director for Cardiovascular Health

Banner University Medical Center-Phoenix

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