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Space travel: Going to space is a real pain in the back


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Astronauts may temporarily gain 2 inches in height but suffer muscle loss and back pain

More countermeasures involving exercise can help alleviate pain and muscle loss



CNN

A six-month stay on the International Space Station can be harrowing for astronauts. Although they can temporarily gain up to 2 inches in height, this effect is accompanied by a weakening of the muscles supporting the spine, according to a new study.

Astronauts have been reporting back pain since the late 1980s, when space missions got longer. Their flight medical data shows that more than half of American astronauts have reported back pain, particularly in the lower back. Up to 28% said it was moderate to severe pain, sometimes lasting the entire duration of their mission.

Things don’t get any better when they return to Earth’s gravity. During the first year after their mission, astronauts have a 4.3 times higher risk of having a herniated disc.

“It’s kind of a lingering problem that’s concerning,” said Dr. Douglas Chang, first author of the new study and associate professor of orthopedic surgery and chief of the department of physical medicine and rehabilitation at the University of California at San. Diego Health. “This study is therefore the first to start from a simple epidemiological description and to examine the possible mechanisms of what is happening with the backs of astronauts.”

Much attention has been focused on intervertebral discs, the spongy shock absorbers that sit between our vertebrae, as the culprits for the back problems astronauts face. But the new study goes against that thinking. In this research, funded by NASA, Chang’s team observed little to no change in the discs, their height or swelling.

What they observed in six astronauts who spent four to seven months on the ISS was enormous degeneration and atrophy of the supporting musculature of the lumbar (lower) spine, Chang said. These muscles are the ones that help us stand, walk, and move our upper limbs in an Earth-like environment, while protecting the discs and ligaments from strain or injury.

In microgravity, the torso elongates, likely due to spinal unloading, in which the curvature of the spine flattens. Astronauts also don’t use lower back muscle tone because they don’t bend over or use the lower back to move, like on Earth, Chang said. This is where the pain and stiffness occur, much like astronauts being in a cast for six months.

MRI scans before and after the missions revealed that the astronauts experienced a 19% decrease in these muscles during their flight. “Even after six weeks of training and reconditioning here on Earth, they only recover about 68% of their losses,” Chang explained.

Chang and his team see this as a serious problem for long-range manned missions, especially when considering a trip to Mars that could take eight or nine months just to reach the red planet. This travel and the potential time astronauts spend in Martian gravity – 38% of Earth’s surface gravity – creates the potential for muscle atrophy and deconditioning.

The team’s future research will also focus on reported neck problems, where there may be even more occurrences of muscle atrophy and a slower recovery period. They also hope to partner with another university on in-flight ultrasounds of the spine, to look at what happens to astronauts when they’re on the space station.

Because no one likes back pain and muscle loss, Chang suggested countermeasures that should be added to astronauts already training two to three hours on the space station every day. While their exercise machines 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 “folded fetal” position that astronauts use in microgravity to stretch the lower back or relieve back pain, Chang suggested yoga. But he knows that’s easier said than done.

“A lot of yoga depends on the effects of gravity, like downward dog, where stretching of the hamstrings, calf muscles, neck, and shoulders is possible with gravity. When you remove that , you may not have the same benefit.

All machines on the space station must also be designed for their weight, size, and even the reverberations they might produce on the station.

Space travel: Going to space is a real pain in the back

Chang and the other researchers brainstormed with a virtual reality team about different exercise programs that would allow astronauts to invite friends, family or even Twitter followers to join them in virtual training, making the daily repetition of their workouts more fun and competitive.

One of Chang’s teammates personally felt this pain. Dr. Scott Parazynski is the only astronaut to have reached the summit of Mount Everest. He had a herniated disc after returning from the ISS to Earth. Less than a year later, when he attempted to climb Everest for the first time, he had to be airlifted. After a process of rehabilitation, he finally reached the top. Now he’s talking to current astronauts about how they can contribute to studies of their health in microgravity.

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  • Keeping astronauts healthy and fit is the least they can do, Chang said.

    “When a crew comes back, they say from one side of the space station, they see this beautiful blue planet,” he said. “Everything dear to them is on this fragile little planet. And they look out the other window and just see infinity stretching out into the darkness, and they come back with a different sense of themselves and their place in the universe.

    “All are committed to furthering space knowledge and stepping forward in every way possible for the next crew.”



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