From shrinking hearts to squashed eyeballs – horrors of how space affects human bodies revealed

TIME in space could shrink your heart, squash your eyeballs and cause your blood cells to destroy themselves.

These are just some of the health conditions astronauts face and scientists worry that longer space travel could cause more issues.

From heart shrinking to kidney stones, we’ve rounded up five quite concerning things that space can do to your body.

Heart shrinking

Time in space can shrink your heart, according to a fairly recent study on a Nasa astronaut.

Last year, it was revealed that Nasa astronaut Scott Kelly’s heart shrank during a 340-day stint on the International Space Station.

Researchers monitored his heart remotely from Earth and noticed it shrink despite the astronaut exercising regularly.

His heart did return to normal size when he came back to Earth.

The researchers concluded that space shrinks hearts because the heart doesn’t have to pump against gravity.

This is said to take some strain off the heart and causes it to lose mass.

Space anemia

Space causes the human body to destroy its own red blood cells and scientists don’t know why.

The strange phenomenon is called space anemia and new research suggests it plagues astronauts even when they return home.

A new study published in Nature Medicine found that space causes the human body to destroy red blood cells at a faster rate than on Earth.

Researchers worked with 14 astronauts over a period of six months.

Their results showed that astronauts were destroying around three million red blood cells every second.

That’s 54% higher than the average rate here on Earth.

Five out of the 13 astronauts who had blood drawn when they landed back on Earth were still anemic.

After a year, their red blood cell destruction was still found to be higher than in people who hadn’t been to space.

According to the study, the longer a person stays in space, the longer they will be anemic on land.

Squashed eyeballs

It’s not uncommon for astronauts to suffer from an array of vision and eye problems after spending a certain amount of time in space.

This is due to the zero-gravity conditions of spaceflight, which can cause body fluids to build in the head.

That puts pressure on the eyeballs and causes a condition called spaceflight-associated neuro-ocular syndrome (SANS).

Other eye issues can range from flattened eyeballs to swollen optic nerves, and bad eyesight.

The risk for these issues is especially high for astronauts who spend more than six months at a time in space.

A body sucking sleeping bag that pulls fluid away from the head and down towards the feet is one potential solution for this issue.

Wasting bones

Time in space can also weaken human bones.

The Nasa website explains: “Nasa has learned that without Earth’s gravity affecting the human body, weight-bearing bones lose on average 1% to 1.5% of mineral density per month during spaceflight.

“After returning to Earth, bone loss might not be completely corrected by rehabilitation; however, their risk for fracture is not higher.”

There’s concern that bone loss could be even worse on longer missions, like those planned for Mars.

Kidney stones

Astronauts are prone to kidney stones because of issues with how bones demineralize from the weightlessness of space.

If a kidney stone gets into the urinary tract it can obstruct it and cause debilitating pain.

It can also result in kidney infections and swelling so a lot of Earth based kidney stone sufferers end up in hospital.

Astronauts don’t have the option

Increased hydration can sometimes help to prevent the problem but scientists are also working on other potential therapies.

In other news, Nasa has its eye on eight asteroids that are all set to make a ‘close approach’ to Earth in January.

Ancient life on Mars is one possible explanation for a recent discovery by Nasa’s Curiosity rover.

And, China has built an ‘artificial moon’ to train its astronauts for future missions.