Before & After Photos: What 288 Days in Space Does to Human Body

After nine gruelling months in space, NASA's stranded astronauts have finally returned to Earth.

However, experts warn that Butch Wilmore and Suni Williams' unplanned stay on the International Space Station (ISS) could have serious health impacts.

Shocking before-and-after images show the damage that months spent in the harsh conditions in space will do to you.

From 'chicken legs' and 'baby feet' to an increased risk of cancer, experts warn that the stranded astronauts could face years of health complications.

As Williams, 59, and Wilmore, 62, emerged from their SpaceX Crew Dragon capsule yesterday, medical teams rushed to help them onto stretchers.

This is a normal procedure for astronauts returning from space since their weakened muscles make it difficult to walk under the force of Earth's gravity.

The pair will now undergo several days of intensive medical checks at NASA's Johnson Space Center in Houston but health experts have already noticed signs of physical decline in the stranded astronauts.

And even while they were on the ISS, experts expressed concern over the pair's gaunt appearance and apparent weight loss.

Vision loss and cognitive decline

Beyond looking unusual, this buildup of fluids in the head can also lead to serious medical complications.

As pressure builds up in the head it presses on the eyes and on the optical nerves causing something called Spaceflight Associated Neuro-Ocular Syndrome (SANS).

Over time, microgravity even causes changes in the shape of the eye including swelling of the optic nerve, flattening of the back of the eye, and the development of folds in the retina.

SANS causes blurry or fuzzy vision in about 70 per cent of all astronauts who go into space.

Astronauts' eyes typically return to normal once they return to Earth, studies have shown, but NASA warns that some effects are permanent.

NASA also warns that the longer astronauts remain in space the greater the risk of vision damage, which will be concerning given Williams and Wilmore's exceptionally long mission.

Likewise, changing pressures in the brain, alongside the stress and lack of sleep, has been linked to cognitive decline in some astronauts.

Studies have shown that astronauts process some tasks significantly slower while in space than on Earth.

Research has also shown that astronauts have impaired working memory and attention, alongside altered risk-taking behaviour.

However, there is currently no evidence that these changes persist once astronauts return to Earth.

Muscle and bone loss

The biggest risks associated with an extended time in space come from the exposure to microgravity.

Away from the pull of Earth's gravity, astronauts' muscles begin to weaken through lack of work.

Over time this leads to muscle atrophy which leaves astronauts frail upon their return to Earth.

To combat the effects of living in low gravity, astronauts exercise for at least two hours per day on the ISS.

But this still isn't enough to stop muscle and bone loss, doctors told the Daily Mail.

Astronauts who spend long periods of time in low gravity 'lose musculature, they lose bone density,' Dr Jaquish said.

'The human body needs the Earth's gravitational pull, and in an absence of that, a lot of things are not functioning correctly.'

Research has shown that a 30 to 50-year-old astronaut who spends six months in space loses about half their strength.

As seen during their dramatic landing yesterday evening, astronauts are typically unable to walk in the crushing weight of Earth's gravity.

Despite following NASA's rigorous exercise routine aboard the ISS, both Williams and Wilmore had to be helped out of the capsule and onto stretchers.

Research has shown that the changes to bone density can be severe and long-lasting, leading to a greater risk of bone fractures or skeletal issues.

Dr Vinay Gupta, a pulmonologist and Air Force veteran said the astronauts could need up to six weeks of rehabilitation to regain their strength, which will include guided exercise and a nutritional plan.

Weight loss

The impacts of microgravity are worsened by the fact that astronauts often struggle to maintain their weight in space.

Frequent nausea and a loss of smell and taste due to pressure in the sinuses means that astronauts lose their appetites.

In November, doctors told DailyMail.com that Williams appeared 'gaunt' in a photo that was taken in September and said that she looked like she had lost weight.

Later that month, an unnamed NASA source told the New York Post that the agency was scrambling to 'stabilize the weight loss and hopefully reverse it.'

The unnamed employee who is 'directly involved with the mission' said that Williams has been 'unable to keep up with the high-caloric diets that astronauts must consume' while on the ISS.

'The pounds have melted off her and she's now skin and bones. So it's a priority to help her stabilize the weight loss and hopefully reverse it,' the NASA source said.

Later that month, Williams hit back at the weight loss 'rumours' in a live video published by NASA, claiming that she had actually put on muscle.

Fluid shift

Additionally, since the body is 70 per cent water, this fluid tends to shift dramatically when in low gravity.

Just as if you were hanging upside down, NASA says that over 5.6 litres of liquid can migrate upwards through the body.

In some cases, this leads to an issue which NASA calls 'puffy face syndrome', which causes severe swelling of the tissues in the head.

At the same time, fluid leaving the lower part of the body leads to what NASA calls 'chicken legs' and 'baby feet'.

This is a condition in which the legs appear unusually small and weakened.

While these cosmetic complications will likely clear up within about three days back in regular gravity, fluid shifting can also lead to serious health issues.

The upward fluid shift their bodies experience on the ISS also increases astronauts' risk of blood clots, specifically through the development of a condition known as Spaceflight Venous Thrombosis (SVT).

Some astronauts who develop SVT have completely recovered after returning to Earth, but others need additional treatment, according to NASA.

Radiation damage

Williams and Wilmore will also have been exposed to extreme levels of space radiation during their extended ISS mission.

In just one week on the ISS, astronauts are exposed to the equivalent of one year's exposure on Earth.

The type of radiation astronauts experience in space is also more dangerous than the common sources of radiation here on Earth.

Space radiation is made up of atoms which have had their electrons stripped away as they accelerated to nearly the speed of light.

Astronauts also have to contend with particles ejected from the sun during solar flares and galactic cosmic rays, high-energy protons and heavy ions from outside our solar system.

When these particles smash into astronauts' bodies, they destroy the chains of DNA in our cells and trigger mutations which can develop into cancers.

This may increase their risk of developing cancer, central nervous system damage, bone loss and some cardiovascular diseases, according to NASA.

'If I was their physician, I would think about a more proactive strategy for cancer screening,' Dr Gupta said.

'We want to take a different approach here, given that they had such a unique exposure history,' he said.

Heart health

It's not just their muscles and bones taking a hit. Low gravity impacts their cardiovascular health too.

This is because blood and other bodily fluids shift upwards towards the head, which means the cardiovascular system doesn't have to work as hard to maintain blood flow to the brain.

This can result in reduced blood volume and reduced function of the heart and blood vessels, according to NASA.

Skin problems

Studies have shown that spending six months on the ISS wreaks havoc on the skin.

One team of researchers found that astronauts' epidermis gets thinner by nearly 20 per cent in space, perhaps due to low gravity, which may dysregulate the skin's ability to grow and repair itself.

Another study found that skin rashes are the most frequently reported clinical symptom during six-month ISS missions, occurring 25 per cent more frequently than they do for the general US population on Earth.

These rashes may result from irritants or allergens found inside the space station, and the weakening effect that low gravity has on the immune system. Skin lesions also take longer to heal in space, according to NASA.

How do astronauts recover from their time in space?

To help the astronauts overcome these long-term impacts, NASA has a specialised rehabilitation program for people returning from space.

Examinations begin as soon as they exit the capsule before they are flown to their crew quarters at NASA's Johnson Space Center in Houston for several more days of routine health checks.

NASA astronauts who return from long ISS missions complete a 45-day rehabilitation program that requires them to exercise for two hours per day, seven days per week.

The program is tailored to the specific needs of each astronaut, according to NASA.