Health Hazard of Space Travel: Astronauts Most Likely to Suffer Back Pain, Spinal Disc Disease

A new study revealed that astronauts traveling in space for long periods of time could most likely to suffer elevated rates of back pain and spinal disc.

The study, published in the journal SPINE, showed that astronauts who have undergone long missions in space may suffer atrophy of the muscles supporting the spine, which don't return to normal even several weeks after their return to Earth.

"We think that the neck is a part of the spine that is particularly susceptible to this loss of gravity," Alan Hargens, a professor of orthopaedic surgery at UC San Diegoand author of the study, in a report from The Verge. "So there need to be better exercises for the astronaut's necks. Right now they don't have anything as far as we know."

For the study, the researchers recruited six NASA crew members that spent four to seven months in "micogravity" conditions on the International Space Station (ISS). Each participant underwent magnetic resonance imaging (MRI) scans of the spine before their space travel, immediately after their return to Earth and one to two months after their return.

The researchers observe an average of 19 percent decrease in the mass of the cross-sectional area of the lumbar paraspinal muscles from pre-flight to immediate post-flight scans. The decrease in the muscle mass remained a month or two later after they returned to Earth, with only about two-thirds of the mass recovered.

Furthermore, the researchers discovered an even more dramatic impact on the functional cross-sectional area of the paraspinal muscles relative to total paraspinal cross-sectional area. The ratio of lean muscles was reduced from 86 percent before flight to 72 percent immediately after they returned to Earth. During the one- to two-month follow-up , the lean muscle ratio recovered to 81 percent, which was still lower compared to pre-flight.

With their findings, the researchers advise some changes to the daily routines and exercise of astronauts during their space missions. At present, the astronauts exercise about two hours each day to strengthen their muscles and bones. However, these routines could have a weakened effect due to the absence of gravity.