Even With Regular Exercise, Astronaut’s Heart Left Smaller After a Year in Space
upstart writes in with an IRC submission for c0lo:
Even with regular exercise, astronaut's heart left smaller after a year in space:
DALLAS - March. 29, 2021 - With NASA preparing to send humans to Mars in the 2030s, researchers are studying the physical effects of spending long periods in space. Now a new study by scientists at UT Southwestern shows that the heart of an astronaut who spent nearly a year aboard the International Space Station shrank, even with regular exercise, although it continued to function well.
The results were comparable with what the researchers found in a long-distance swimmer who spent nearly half a year trying to cross the Pacific Ocean.
The study, published today in Circulation, reports that astronaut Scott Kelly, now retired, lost an average of 0.74 grams - about three-tenths of an ounce - per week in the mass of his heart's left ventricle during the 340 days he spent in space, from March 27, 2015, to March 1, 2016. This occurred despite a weekly exercise regimen of six days of cycling, treadmill, or resistance work.
Journal Reference:
James P. MacNamara, Katrin A. Dias, Satyam Sarma, et al. Cardiac Effects of Repeated Weightlessness During Extreme Duration Swimming Compared With Spaceflight, Circulation (DOI: 10.1161/CIRCULATIONAHA.120.050418)
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