Spending an extended period of time in microgravity environments such as those found aboard space stations and other spacecraft can wreak havoc on an astronaut’s spine, new research reveals. Appearing in the journal Spine, the study indicates that the muscles supporting the spinal column often waste away over several months in space, and that they can take a long time to recover after returning to Earth.
The study involved six astronauts, all of whom spent between four and seven months aboard the International Space Station (ISS). Before heading into orbit, the researchers used MRI to examine the astronauts’ lumbar paraspinal muscles, and then took another reading immediately after they returned home, as well as another 33 to 67 days later.
These scans revealed that the cross-sectional area of these muscles decreased by an average of 19 percent over the course of the astronauts’ missions. Even by the time the follow-up scans were taken up to two months after re-entry, only 68 percent of this loss had been recovered.
Furthermore, while the cross-sectional area of the lumbar paraspinal muscles had equaled 86 percent of the total paraspinal cross section pre-flight, this dropped to 72 percent immediately after the mission.
The results of this study indicate that long missions in space carry a significant risk of muscle atrophy, and could well explain why over half of all NASA astronauts complain of back pain while in orbit. Returning astronauts also face an increased risk of slipping a disc during their first year back on Earth, and are 4.3 times more likely to do so than the average Earthling.
On top of this, spaceflight has been found to make people between 3 and 5 centimeters (about 2 inches) taller, as the low gravity causes “spinal unloading”, whereby the spine becomes less curved and compact as the weight of the body is not compressing it.
As a remedy to this, the study authors recommend astronauts do regular space yoga in order to exercise their back and core muscles while on missions.