NASA Twin Study reveals space's effect on telomeres, bones and more

NASA's Twin Study has revealed interesting information about the effects space travel has on the human body. The study involves determining the genetic changes experienced by NASA astronaut Scott Kelly, who spent time in space, by comparing his health data with that of his identical twin brother Mark who remained on Earth. Though the project is still underway, NASA researchers recently detailed some preliminary findings, revealing that space does indeed leave a mark on human health.

NASA detailed the early results in Texas recently during the Human Research Program's Investigator Workshop. According to work done so far, Scott Kelly's time in space resulted in a lengthening in the portion of chromosomes known as telomeres. That's an interesting change given that as a person ages, their telomeres — which help protect the chromosomes — get shorter.

It's important to note that you don't have to go to space to experience this effect, though — past studies have found that fasting, for example, can have a positive effect telomeres. NASA agrees that the calorie restriction and exercise experienced during the mission may play a role in the change, but that doesn't appear to be the entire story. According to researchers, Kelly's telomeres began shortening again once he returned to Earth.

Kelly also demonstrated a slight impairment in his cognitive functions, namely his memory was a bit slower and less accurate than previously. As well, the astronaut's time in space seems to have stunted his bone formation, at least in the latter portions of the trip. These are preliminary results, however, and researchers are still working out what all has changed between the two brothers.

In a statement on the preliminary findings, NASA explained that it didn't take long after returning to Earth for Kelly's observed biological changes to start returning to normal. Some genes were able to return to normal in just hours or days, whereas other changes were found to still exist half a year later.