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Did Astronaut Scott Kelly’s Heart Shrink From Space Travel? | Snopes.com

In spring 2021, news headlines claimed that American astronaut Scott Kelly’s coronary heart shrank in mass by greater than one-quarter when he spent about one yr on the Worldwide House Station in 2015 and 2016.

The information tales have been purportedly based mostly on a examine printed within the journal Circulation, a analysis arm of the American Coronary heart Affiliation (AHA) that publishes peer-reviewed analysis about cardiovascular well being and ailments.

Utilizing the journal’s web site, we decided the analysis to be genuine. We obtained a duplicate of the examine’s abstract, titled “Cardiac Effects of Repeated Weightlessness During Extreme During Swimming Compared With Spaceflight,” which was printed on March 29, 2021, and defined the important thing findings of the analysis venture trying to find out the impact of Earth’s gravitational pull on the human cardiovascular system.

Led by Dr. Benjamin Levine, a professor of inside medication on the College of Texas Southwestern Medical Heart and Texas Well being Presbyterian Dallas, the researchers analyzed the left ventricle (LV) of two individuals’s hearts: Kelly’s and that of Benoît Lecomte, a long-distance endurance swimmer who tried to cross the Pacific Ocean in 2018. (Observe: The left ventricle is the most important and strongest of 4 coronary heart chambers, pumping oxygenized blood all through the physique.)

The experiment checked out Kelly’s coronary heart earlier than, throughout, and after his area journey — he exercised virtually daily in area to keep away from dropping muscle mass — in addition to studied Lecomte’s cardiovascular system over the course of his 159-day swim. The researchers concluded:

“LV mass declined at comparable charges in each people. B.L.’s mass dropped by 0.72 g/wk (95% CI, −0.14 to 1.58) and S.Ok.’s mass dropped by 0.74 g/wk (95% CI, 0.13–1.34) when linear regression is utilized.” 

In different phrases, regardless of each males’s bodily exercise, their hearts shrank at price of about 1/40th of an oz. every week (0.72 g/wk for Lecomte and 0.74 g/wk for Kelly). 

For the astronaut, that meant for a 27% decline in mass general, as proven by way of the examine’s graph documenting the sizes of the 2 males’s left ventricle over time (displayed beneath). Kelly’s left ventricle went from 6.7 ounces to 4.9 ounces after the area journey, in response to the experiment.

“His coronary heart tailored to the lowered gravity,” Levine informed The New York Times. “It didn’t grow to be dysfunctional, the surplus capability didn’t get lowered to a important stage. He remained fairly match. His coronary heart shrank and atrophied sort of as you’d anticipate from going into area.”

Contemplating that proof, we price this declare “True.”

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