Is Distance Running Healthy for Your Heart?

The effects of long distance running is debated regulary by medical experts. While it is true that long-term endurance athletes have had some scarring noted in the heart muscle, it is at this point an association and not a causation. There is concern because if scarring of the heart muscle (fibrosis) becomes severe, it can lead to thickening of portions of the heart which can impact heart functioning. The discussion really hinges on two articles.

In a study by Matthew Wilson, which was published in the Journal of Applied Physiology, advanced imaging techniques were used to look at the hearts of three groups of people: 12 lifelong 50- to 67-year-old athletes, 20 age-matched control subjects, and 17 younger (26- to 40-year-old) athletes. Heart-muscle scarring was detected in four of the lifelong endurance athletes and was not found in any of those in the control group nor in the younger athletes. So, the association of heart scarring and endurance running is there. But additional research is needed to draw a conclusion that endurance training causes the scarring and is therefore bad for you.

Another study, conducted by Begona Benito and published in Circulation, was based on rats. Researchers noted changes in rat hearts similar to those seen in exercising humans. Interestingly, the findings resolved after an eight-week rest period (half the exercise period). Still, it is difficult to make the jump to humans.So what does this mean for those of us who participate in endurance training and events? It is hard to say. People who run an occasional marathon and spend the rest of their lives staying fit with 30 to 60 minutes of exercise most days of the week are not likely to be affected. A percentage of people who spend a lifetime training hard for marathons and other strenuous endurance events may be at risk for some heart-muscle scarring. Even so, we are not sure what that means in terms of outcomes.

I would recommend backing off on training when you have a viral illness. A viral infection causes inflammation in your blood vessels, and there is potential to cause scarring in the vessels.

From my personal knowledge, many involved in this research are endurance athletes who have not stopped training. As always, if you have concerns about your heart or if you experience chest pain, unexpected fatigue, shortness of breath, racing heart, or feeling like you are going to black out during or after exercise, you should see your physician.

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