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Butch Wilmore and Suni Williams may face health changes after 9 months in space. Learn about the main physical and physiological impacts that weightlessness can cause
After nine months on the International Space Station, the astronauts Butch Wilmore and Suni Williams finally returned to Earth. The mission, which was supposed to last only ten days, ended up lasting almost a year.
Now, the two are facing the physical effects of a long stay in space. Spending so much time in microgravity causes several changes in the human body.
These changes in the human body range from temporary growth in height to vision problems, loss of bone and muscle mass. NASA already has experience dealing with these consequences, but each mission brings new observations.
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Temporary increase in height
One of the most curious changes is the increase in height. Without Earth's gravity compressing the spine, the spinal discs expand. As a result, astronauts grow up to five centimeters in space.
But this effect doesn't last long. As soon as they return to Earth, their spines return to normal. Astronaut Scott Kelly, for example, lost his extra height in just two days. Wilmore and Williams are expected to go through the same process.
More fragile bones in astronauts' bodies
The absence of gravity also affects the bones. In space, the bones do not need to support the weight of the body. This causes a loss of density, especially in the hips and legs, causing important reactions in the astronauts' bodies.
According to NASA, astronauts lose between 1% and 1,5% of their bone density per month in microgravity. This loss can lead to chronic pain, reduced mobility and a risk of fractures. After returning, recovery is gradual, but it can leave after-effects.
Weakened muscles
The weightless environment also causes muscle atrophy. Without the effort to move or keep the body upright, muscles lose strength over time.
Shenhav Shemer, a biology professor at the Technion in Israel, explained that the effect may be more pronounced in women, like Suni Williams. This is due to hormonal factors and lower muscle mass.
For this reason, NASA requires astronauts to exercise for at least two hours a day during their missions. Exercise bikes and treadmills are used to reduce the negative effects. According to the agency, without them, they would not even be able to walk when they return to Earth.
Vision problems
Another common side effect is Spaceflight Associated Neuro-ocular Syndrome (SANS). This condition affects the vision of more than half of astronauts.
The change in fluid distribution in the body is thought to increase pressure on the optic nerve. This can flatten the eyeball and swell the nerve, affecting vision and blood flow.
Despite the symptoms, there are no records of permanent vision loss after space missions. Still, scientists continue to investigate the causes and ways to prevent it.
Less efficient heart
In the absence of gravity, the heart works less hard. It doesn't have to pump blood against the gravitational force, which can make it smaller and less efficient.
Upon returning, astronauts may experience low blood pressure and dizziness. These effects, however, are usually temporary. Studies show that, over time, the cardiovascular system recovers well. Some astronauts even have better heart health than the average person.
Compromised balance in the astronauts' bodies
The vestibular system, which helps with balance, also suffers in space. Without gravitational reference, the astronauts' bodies adapt to a new pattern of movements.
When they return to Earth, this readaptation causes instability and disorientation. Astronauts call this “space legs.” It takes a while before they can walk steadily again.
Radiation and cancer risk
Outside the protection of the Earth's atmosphere, astronauts are more exposed to radiation. This increases their risk of cancer.
NASA monitors this exposure with specific equipment, such as dosimeters, and sets limits. The goal is to keep this risk to a maximum of 3% above what an average person on Earth would face.
Changes in the Human Body: The Little Things
Even with so many studies, not everything is predictable. Some changes in the human body only appear over time, and each astronaut reacts differently.
Matthew Dominick, who also spent months on the Space Station, commented that small, everyday things become challenges. “The big things you expect, right? Getting disoriented. Getting dizzy. But the little things, like sitting on a hard chair, right? My back hasn't sat on a hard thing in 235 days."
Fellow missionary Jeanette Epps reinforced this idea. “Everyone is different. And that's the part you can't predict.. One problem that Matt may have, I may not have, but I may have several things that he doesn't have. And so, and we've done different experiments on board. So we don't know how we're going to respond when, when we return and how quickly. And each day is better than the day before.. "
Despite the difficulties, the astronauts returned and are undergoing an intense phase of readaptation. Wilmore and Williams now face the challenge of returning to their Earthly routine after nine months floating in space. Their experience will help NASA better understand the effects of space and changes in the human body — and prepare for future long-duration missions.
With information from New York Post.
