IT takes several years to recover from a six-month spaceflight – the average amount of time an astronaut is posted to the International Space Station (ISS).
Once-stranded astronauts Butch Wilmore and Suni Williams topped that sum by several months, spending 286 days in total on the ISS.
The pair, who returned to Earth on 18 March, are about to embark on a 45-day rehab to recover from their nine months in space.
Though there can be ongoing health concerns long after astronauts have their feet on the ground.
Squashed eyeballs
Astronauts can experience changes to their eyes during spaceflight – an impairment that can last up to 90 days post-flight.
Microgravity can cause blood and fluid to shift towards the head, which can squash astronauts’ eyeballs.
The changes in eye structure can also cause impairments to vision – although Nasa notes that fluid pressure may not be the sole cause of vision changes.
Shrinking hearts
A study on astronaut Scott Kelly, who previously spent 340 days in space, found that his heart shrank during his campaign.
Despite exercising for roughly two hours per day, the effects of weightlessness in space resulted in loss of heart mass and cardiac atrophy.
Similar effects were experienced by athlete Benoît Lecomte, who swam 2821 kilometers over 159 days, and experienced similar levels of weightlessness from water.
Increased cancer risk
In just one week aboard the ISS, astronauts are exposed to the equivalent of one year’s radiation exposure on Earth.
Nasa has warned this can increase the risk of an astronaut developing cancer later in life.
Though the space agency notes that the risk depends on how long an astronauts mission was, the solar conditions at the time, their individual radioactivity and their age at exposure.
Brittle bones
Astronauts lose between 1% and 2% of bone density for every month spent in space, according to research by Canada’s University of Calgary.
This is due to the lack of gravity taking the pressure off their legs when it comes to standing and walking.
But it can lead to brittle bones, osteoporosis and fractures.
Kyle Zagrodzky, founder of OsteoStrong, a company that treats osteoporosis, previously told The Sun that Wilmore and Williams’ could return with “the bones of an 80-year-old”.
He said their ages, 61 and 58 respectively, will influence them “poorly” even if they were exercising.
“They may have, in eight months in outer space, 10 to 20 years of bone loss even with exercise,” added Zagrodzky.
Slow brain
A study published late last year found that astronauts may also experience a temporary slowing of “cognitive performance”.
After analysing 25 astronauts, scientists found they had slower response times, working memory and attention compared to when they were on Earth.
Some of these changes did not resolve until the astronauts were back on the ground.
Baby skin
So-called ‘baby skin’ is a common phenomena when astronauts return to Earth.
As astronauts float in space, the microgravity environment means their clothing hovers slightly above the skin.
It gives astronauts a heightened level of sensitivity that humans only really experience as babies.
This, in turn, also makes clothes back on Earth feel like sandpaper, as their bodies aren’t used to the near-constant contact with fabric.