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They called it the “perfect nature versus nurture” experiment: astronaut Scott Kelly was sent to the International Space Station for nearly a year, while his identical twin, astronaut and now Senator Mark Kelly, remained on Earth. When Scott Kelly returned home in March 2016, scientists compared his DNA and body makeup to that of his twin and found that Scott was 5cm taller than he had been and had a lower body weight, among other changes (most of which have since changed) . reversed). Now, according to a study published Monday in the journal Circulationannounced another major shift: The mass of Kelly’s heart shrank from 6.7 ounces to 4.9 ounces, or about 27%, during his travels to the cosmos, although the astronaut did not appear to be experiencing major repercussions. “He did remarkably well for over a year,” said study co-author Benjamin D. Levine, a professor of internal medicine at the University of Texas Southwestern Medical Center. New York Times
CNN’s explanation: When humans are dealing with Earth’s gravity, the heart has to work harder to pump blood. With weightlessness, however, the heart does not have to work as hard and so it atrophies. Levine tells Times that Kelly’s heart did that without becoming “dysfunctional.” The study also looked at Benoit Lecomte, an endurance swimmer who attempted to cross the Pacific in 2018. size almost as fast. While Kelly did well, he also worked out quite a bit in space using exercise equipment – which probably didn’t weaken his heart any further. Scientists are concerned that astronauts on future missions could be prevented from training due to injury, illness or broken equipment, and that they could suffer more serious consequences. NASA is funding further heart research involving astronauts on both long and short journeys. (Read more discovery stories.)