Astronauts have been reporting back pain since the late 1980s, when space missions became longer. Their medical flight data show that more than half of American astronauts have reported back pain, especially in the lower back. Up to 28% said it was moderate to severe pain that sometimes lasted during their mission.
Things don’t improve when they return to Earth’s gravity. In the first year after the mission, astronauts have a 4.3 times higher risk of a herniated disc.
“It is a kind of permanent problem that is significant and causes concern,” said Dr. Douglas Chang, the first author of the new study and associate professor of orthopedic surgery and head of the Department of Physical Medicine and Rehabilitation at the University of California, San Diego Health. “So this study was first taken from just an epidemiological description and an overview of possible mechanisms for what happens to astronauts’ backs.”
Much attention has been focused on the intervertebral discs, the spongy shock absorbers that sit between our vertebrae, as the culprit for the back problems faced by astronauts. But the new study contradicts that thinking. In this research, funded by NASA, Chang’s team noticed little or no change in the disks, their height or swelling.
What they noticed in the six astronauts who spent four to seven months on the ISS was massive degeneration and atrophy of the supporting muscles in the lumbar (lower) spine, Chang said. These muscles help us stand upright, walk, and move our upper extremities in an Earth-like environment, while protecting discs and ligaments from strain or injury.
In microgravity, the torso lengthens, most likely due to spinal unloading, in which the spine curves. Astronauts also do not use muscle tone in the lower back because they do not bend or use the lower back to move, as on Earth, Chang said. Pain and stiffness occur here, much like astronauts have been in a severed body for six months.
MRI scans before and after the missions revealed that the astronauts had a 19% reduction in these muscles during the flight. “Even after six weeks of training and repairing one Earth here, they only recoup about 68% of their losses,” Chang explained.
Chang and his team consider this a serious issue for long-term missions, especially when considering a trip to Mars that could take eight or nine months just to reach the Red Planet. That journey and the potential time astronauts spent in Martian gravity – 38% of Earth’s surface gravity – creates the potential for muscle atrophy and deconditioning.
Future research by the team will also look at reported neck issues where there may be more muscle atrophy and a slower recovery period. They also hope to participate in another university on inflammatory spinal ultrasounds, to see what happens to astronauts while they are on the space station.
Yoga in space?
Since no one likes back pain and muscle loss, Chang suggested countermeasures to which should be added the already two- to three-hour exercises that astronauts have on the space station every day. Although their exercise devices focus on a range of issues, including cardiovascular and skeletal health, the team believes space travelers should also include a spine-focused core strengthening program.
In addition to the “fetal crease” position, astronauts use microgravity to stretch the lower back or relieve back pain, Chang suggested yoga. But he knows it’s easier said than done.
“A lot of yoga depends on the effects of gravity, like dogs down, where stretching is possible through the knee muscles, the muscles of the muscles, the back of the neck and the shoulders due to gravity. When you remove that, you may not have the same benefit.”
All machines on a space station must also be designed with respect to weight, size, and even echoes that could be produced on the station.
Chang and other researchers came to life with a virtual reality team about various exercise programs that would allow astronauts to invite friends, family or even Twitter followers to join them in a virtual exercise, making daily repetitions of their exercises more fun and competitive.
Keeping astronauts healthy and healthy is the least they can do, Chang said.
“When the crew comes back, they say on one side of the space station, they see this beautiful blue planet,” he said. “All they like is on this fragile little planet. And they look out the other window and just see infinity stretching into the darkness, and they come back with a different meaning to themselves and their place in space.
“They are all committed to further learning about space and taking steps forward in any way possible for the next crew.”