
Long spaceflights and endurance swimming can ‘shrink the heart’
SPLSpending very long periods of time in space has something in common with extreme endurance swimming: both can cause the heart to shrink.That's the conclusion of a study that compared the effects of astronaut Scott Kelly's year in space with a marathon swim by athlete Benoît Lecomte.Both remove the loads on the heart that are usually applied by gravity, causing the organ to atrophy.Exercise wasn't enough in either case to counteract the changes to the heart.The study was led by Dr Benjamin Levine, professor of internal medicine at the University of Texas Southwestern Medical Center in Dallas, and is published in the journal Circulation.The research has implications for very long-duration journeys in space - such as the expeditions to Mars which Nasa plans to mount in coming decades.Histo...