Long distance running: safe for women’s hearts?

by Carolyn Thomas   ♥  @HeartSisters

Eighteen years ago, when my YWCA running group completed our very first Half-Marathon event, we all crossed the finish line together holding hands. And weeping. Tear-streaked race number bibs are how you can spot first-time distance racers.

There was interesting news for distance runners last month from the European Society of Cardiology meetings in Stockholm: distance runners appear to develop some transient heart changes during races, but overall these activities don’t seem to mean long-term cardiac harm for the vast majority of runners.

But there do seem to be some gender differences in heart changes, particularly among black women.  

For example, Dr. Sanjay Sharma, professor of cardiology at Kings College in London, reported in Stockholm that about 3% of black women athletes actually have a heart muscle wall thickness greater than 11 mm — a level that’s not exceeded by white women athletes. In black elite women athletes, the left ventricular wall thickness can reach as much as 13 mm — a level of heart enlargement that would be considered abnormal for white women. Dr. Sharma suggested:

“If sports policymakers used data derived only from white athletes regarding what constitutes ‘normal’ heart function, it could unfairly discriminate against black athletes by leading to unnecessary investigation or even race disqualification.”

In a series of several research reports presented in Stockholm, doctors found:

• Older runners — those over age 50 — developed some cardiac changes after running a marathon, but the changes did not exceed normal ranges.
• There are ethnic and sexual differences in changes in heart muscle that should be recognized before athletes with enlarged hearts are disqualified from competition.
• No significant cardiac changes occurred among participants who were engaged in a week-long overland and water endurance exercise program.
• Ultra-endurance running — races of 50 to 100 miles — resulted in elevation of cardiac enzymes called troponin-1 which could be related to heart muscle damage; many of these runners also developed EKG changes.

Aside from those ultra-distance studies, the lack of longterm damage to these runners’ hearts may point to human genetic makeup. Germany’s Dr. Stephen Gielen of the University of Leipzig and a spokesman for the European Society of Cardiology, told MedPage Today:

“In evolution, we were selected out as hunter-gatherers where we would run and hunt miles from home to find enough food for the day. It is astonishing the enormous exercise that the human heart can endure.”

And speaking of ‘enormous exercise‘, if you’re a triathlete, there may be even more good news. Apparently, the hearts of triathletes adapt to the rigors of training and competition by becoming more efficient at achieving optimal heart health, researchers in Germany reported.

Triathletes are the elite jock chic of the sports world compared to the rest of us lazy dolts. They believe that running a puny little 26.2 mile marathon is not hard enough. Triathlon is a multi-sport competition involving swimming, cycling and running in succession. Compared to the German control group studied who were recreationally active no more than three hours per week, the study’s triathletes had resting heart rates that were 17% lower than those in the control group. This lower resting heart rate is associated with greater heart blood supply and more efficient heart function.

Lead researcher Dr. Michael M. Lell of the University of Erlangen-Nuremburg explained that the way triathletes train combines both endurance training (running and swimming) and resistance training (weightlifting and cycling). Excessive training in either resistance or endurance pursuits leads to specific heart adaptations. His study was published online and in the October 2010 print issue of the journal Radiology. He adds:

“The hearts of the triathletes in our study are stronger and able to manage the same workload with less effort.”

Meanwhile, Dr. Gielen added that those of us who decide to take up long-distance running and are over age 40 should undergo cardiovascular screening before hitting the road.

According to a small study of 20 low-risk runners presented at the Canadian Cardiovascular Congress 2010 in Montreal, marathon running can cause temporary increases in swelling and inflammation of the heart muscle, as well as decreases in blood flow, and the less physically fit the runner, the more widespread this damage. Cardiologist Dr. Eric Larose of the Quebec Foundation for Health Research in Quebec City explained:

“There is no permanent damage to the heart, but there is some temporary, reversible damage that occurs during the run. Heart function returns to baseline in three months.”

Cardiologist and marathon runner Dr. Paul Thompson of Connecticut told The New York Times recently that running’s health benefits outweigh the cardiac risks, but they do not absolutely inoculate anyone against heart disease:

“Genetics, viruses, bad habits from the past, bad diet or plain bad luck can contribute to the development of plaques within the coronary arteries or of heart damage like cardiomyopathy, an unnatural enlargement of the heart muscle, which running simply cannot prevent.“

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See also:

• The Haywire Heart: (a book about the link between endurance sports and heart disease by cardiologist/athlete Dr. John Mandrola with journalist Chris Case and cyclist Leonard Zinn)
• Returning to Exercise (and Training) After Heart Surgery (THE best and most comprehensive overview on this topic I’ve seen yet, written by cardiologist and triathlete Dr. Larry Creswell; especially useful for heart patients who have been regular exercisers before their cardiac event and are wondering how to safely resume their routine)
• Can Exercise Trigger a Heart Attack?
• Too Cold to Walk Today? Take a Heart-Smart Mall Walk!
• Women’s Heart Health Advice: “Walk Far, Walk Often!”
• Why Your Heart Needs Work – Not Rest – After a Heart Attack
• What Prevents Heart Disease “Better Than Any Drug”?