Astronauts have reported back pain since the late 1980s, when space missions grew longer. Their aeromedical data show that more than half of the US astronauts reported back pain, especially in the lower back. Up to 28% indicated there was moderate to severe pain that sometimes lasted the duration of their mission.
Things don't improve when they return to Earth's gravity. In the first year after their mission, astronauts are 4.3 times more likely to have a herniated disc.
"It's a kind of persistent problem that gives cause for concern," said Dr. Douglas Chang, first author of the new study and associate professor of orthopedic surgery and chief physician for physical medicine and rehabilitation at the University of California San Diego Health. "So this study is the first that only deals with an epidemiological description and examines the possible mechanisms for the processes on the back of the astronauts."
Much attention has been paid to the intervertebral discs, the spongy shock absorbers that sit between our vertebrae, as the cause of the back problems that astronauts face. But the new study contradicts this idea. In this NASA-funded investigation, Chang's team found little or no changes in the intervertebral discs, their size, or swelling.
What they observed in six astronauts who had spent four to seven months on the ISS was tremendous degeneration and atrophy of the supporting muscles in the lumbar spine (lower spine), said Chang. These muscles help us to stay upright, walk, and move our upper extremities in an environment like the Earth, while protecting intervertebral discs and ligaments from stress or injury.
In weightlessness, the trunk lengthens, probably due to the relief of the spine, which causes the spine to flatten. Astronauts also don't use the muscle tone in their lower back because they don't bend over the earth or use their lower back to move like on earth, Chang said. Pain and stiffening occur here, much like when the astronauts were cast in a body for six months.
MRI scans before and after the missions showed that the astronauts experienced a 19% decrease in these muscles during their flight. "Even after six weeks of training and maintenance on Earth, only about 68% of the losses are recovered," Chang said.
Chang and his team consider this a serious problem for long-term manned missions, especially when considering a trip to Mars that could take eight or nine months to reach the Red Planet. This journey and the potential time of astronauts in Mars gravity – 38% of surface gravity on Earth – create the potential for muscle atrophy and conditioning.
The team's future research will also address reported neck problems, which may result in muscle wasting and a slower recovery period. They also hope to work with another university to investigate what happens to astronauts on the space station.
Yoga in space?
Since no one likes back pain and muscle wasting, Chang suggested countermeasures that should be added to the space station's two to three-hour workout astronauts every day. Although their exercise equipment focuses on a number of issues, including cardiovascular and skeletal health, the team believes that space travelers should also include a core strengthening program that focuses on the spine.
In addition to the "fetal tuck" position, astronauts use zero gravity to stretch their lower back or relieve back pain, Chang Yoga suggested. But he knows that it's easier said than done.
"A lot of yoga depends on the effects of gravity, like down on the dog, where stretching through the Achilles tendon, calf muscles, neck and shoulders is possible due to gravity. If you remove this, you may not have the same Use . "
All machines on the space station must also be designed in terms of weight, size, and even the reverberation that they could produce on the station.
Chang and the other researchers discussed various exercise programs with a virtual reality team that astronauts could use to invite friends, family members, or even Twitter followers for virtual training to make the daily repetition of their training more entertaining and competitive.
Keeping the astronauts healthy and fit is the least they can do, Chang said.
"When a crew comes back, they say on one side of the space station that they see this beautiful blue planet," he said. "Everything that is close to their heart is on this fragile little planet. And they look out of the other window and see how infinity expands into the dark, and they return with a different feeling for themselves and their place in the world Universe back.
"They are all committed to improving space knowledge and making incremental progress as best as possible for the next crew."