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Who has a bigger heart: a 150-lb marathoner, or a 300-lb World’s Strongest Man competitor? And more importantly, whose heart is healthier? Believe it or not, this is an actual study just published in the Journal of Strength & Conditioning Research by scientists in Lithuania. They studied 8 Strongmen, 10 marathoners (nationally or internationally competitive in both cases), plus 9 controls.
In general, you wouldn’t expect strength training to do much for the heart — but these competitors are so extreme that you might expect to see some differences, the researchers argue:
Strongmen with their Herculean strength conduct extremely arduous exercises such as lifting, holding, carrying (hundreds of kilograms), pulling, and pushing (tons) during training and competitions, and such tasks trigger a pronounced cardiac pressure overload and, when conducted over an extended period of time, might be expected to impact cardiac size and function to a greater extent than participation in other types of resistance sport.
The results shows that the Strongmen do have big hearts, but pretty much exactly in proportion to their bodies, whereas marathoners have big hearts but small bodies. For example, the thickness of the posterior wall of the heart was, on average, 11.81, 11.82 and 10.99 mm in the Strongmen, marathoners and controls; but when adjusted relative to body surface area, the values were 7.50, 8.56 and 7.50. More to the point, the hearts of the Strongmen don’t appear to function quite as well (the “E/A” column is a measure of diastolic function):
The Strongmen also fared worse on measures of plasma lipids. What does this all mean? None of the results are particularly surprising. But I suppose if you’re a skinny little marathoner, it’s kind of cool to know that your heart is just as big as the dude twice your size single-handedly hauling an 18-wheeler up a hill on TV.