Long space travel and endurance swimming have something in common. Both can make the heart shrink. That's according to a study that compared the impact of astronaut Scott Kelly's year in space with athlete Benoît Lecomte's marathon swimming. The study was conducted by Dr. Benjamin Levine, professor of internal medicine at the University of Texas Southwestern Medical Center at Dallas. But what do both cases have in common that makes them have the same effect on the heart?
As well asduring space travel, as well as when staying in the water for a long time, the attraction is missing. This weightlessness means that the organ lacks the usual stress and this leads to the heart shrinking. Even exercises couldn't reverse this. Long space travel and endurance swimming permanently shrink the heart.
“One of the things we have learned over many years of study is that the heart is remarkably plastic. “So the heart adapts to the load that is put on it,” says Professor Levine, who is also director of the Institute for Exercise and Environment. “In space travel, one of the things that happens is you don’t have to pump blood uphill anymore because you’re not pumping against gravity.”
Scott Kelly spent 340 days aboard the International Space Station (ISS), while Benoît Lecomte attempted to cross the Pacific after crossing the Atlantic. This attempt ended after over 159 days and 2821 km. If you add up the swimming time per day and the swimmer's sleep during this marathon, you get an average of 17 hours that the heart spent in a lying, i.e. horizontal, pose, instead of the usual horizontal position. The conditions are almost identical in both cases. Both men's hearts stopped pumping blood, causing it to begin losing mass.
Space travel of longer duration is unfavorable for the heart
There is also further risk to this vital organ from long space travel. The higher radiation levels in space could accelerate coronary heart disease. Astronauts are checked for arteriosclerosis. But they are mostly middle-aged when they go into space, and scientists know this is a problem that increases with age.
The Studywas published in the magazine Circulation.
