After nine grueling months in space, NASA’s stranded astronauts have finally made their way back to Earth.
However, experts caution that Butch Wilmore and Suni Williams’ unexpected extended stay aboard the International Space Station (ISS) could have significant health repercussions.
Stunning before-and-after images highlight the alarming toll that months spent in the harsh environment of space can take on the human body.
From “chicken legs” and “baby feet” to a heightened risk of cancer, experts warn that the stranded astronauts could face long-term health complications.
When Williams, 59, and Wilmore, 62, emerged from their SpaceX Crew Dragon capsule yesterday, medical teams quickly assisted them onto stretchers.
This is standard protocol for astronauts returning from space, as their weakened muscles make it challenging to walk under Earth’s gravitational force.
The two astronauts will now undergo several days of thorough medical assessments at NASA’s Johnson Space Center in Houston, but health experts have already observed signs of physical decline.
Even during their time aboard the ISS, experts voiced concerns about their noticeably gaunt appearance and apparent weight loss.
After nine grueling months in space, Suni Williams (pictured) and Butch Wilmore have finally returned to Earth. However, shocking before-and-after images reveal the toll their unexpected time in space has taken on their bodies.
Even while in space, health experts expressed concern that Butch Wilmore (pictured) and Suni Williams were experiencing significant weight loss and muscle atrophy.
Throughout their nine months on the ISS, health experts voiced concerns about Williams’ “gaunt” appearance. A loss of appetite, often caused by frequent nausea in space, is common and can result in astronauts losing dangerously high amounts of weight.
The most significant effects of time in space result from exposure to microgravity and intense radiation. The absence of Earth’s gravitational pull causes astronauts’ muscles to weaken, leading to difficulties with walking when they return.
Vision Loss and Cognitive Decline
Beyond the unusual appearance, the fluid buildup in the head can lead to serious medical issues.
As pressure increases in the head, it compresses the eyes and optic nerves, resulting in a condition called Spaceflight Associated Neuro-Ocular Syndrome (SANS).
Over time, microgravity causes structural changes to the eye, including swelling of the optic nerve, flattening of the eye’s rear, and the formation of folds in the retina.
SANS affects around 70% of astronauts, leading to blurry or fuzzy vision.
While astronauts’ eyes generally return to normal after returning to Earth, studies have shown that some effects can be permanent.
NASA cautions that the longer astronauts spend in space, the greater the risk of lasting vision damage, a concern for Williams and Wilmore given their exceptionally long mission.
Similarly, changes in brain pressure, along with stress and sleep deprivation, have been linked to cognitive decline in some astronauts.
As microgravity causes fluid to shift into the head, it not only alters appearance but can also result in vision loss due to a condition known as Spaceflight Associated Neuro-Ocular Syndrome (SANS).
Approximately 70 percent of astronauts experience some degree of vision loss, with symptoms worsening the longer they remain in space. This is a particular concern given Suni Williams’ exceptionally extended time in space.
Along with physical challenges, Williams and Wilmore are also at risk of cognitive decline. Studies have shown that astronauts experience slower processing speeds and weakened short-term memory while in space.
Although low gravity, stress, and sleep deprivation contribute to cognitive decline while astronauts are in space, research indicates that these symptoms typically subside once they return to Earth.
Studies show that astronauts perform some tasks significantly slower in space compared to Earth. Additionally, astronauts experience impaired working memory, reduced attention, and altered risk-taking behavior while in space.
However, there is no evidence to suggest that these changes persist after their return to Earth.
Muscle and Bone Loss
The greatest risks of prolonged time in space stem from exposure to microgravity.
Without Earth’s gravitational pull, astronauts’ muscles weaken due to lack of use. Over time, this leads to muscle atrophy, leaving astronauts physically frail upon their return.
To counteract the effects of living in low gravity, astronauts exercise for at least two hours each day aboard the ISS.
Time spent in microgravity results in a significant loss of muscle and bone mass, which can be both severe and long-lasting.
Research has shown that an astronaut aged 30 to 50 who spends six months in space can lose about half of their strength.
But this is still not enough to prevent muscle and bone loss, doctors told the Daily Mail.
Astronauts who spend extended periods in low gravity “lose musculature and bone density,” Dr. Jaquish explained. “The human body relies on Earth’s gravitational pull, and without it, many bodily functions don’t work as they should.”
Research shows that an astronaut aged 30 to 50 who spends six months in space can lose about half of their strength.
As demonstrated during their dramatic landing yesterday evening, astronauts typically struggle to walk under the intense force of Earth’s gravity.
Despite adhering to NASA’s strict exercise regimen aboard the ISS, both Williams and Wilmore needed assistance to exit the capsule and were carried onto stretchers.
Research indicates that changes in bone density can be severe and long-lasting, increasing the risk of fractures or other skeletal issues.
Dr. Vinay Gupta, a pulmonologist and Air Force veteran, stated that the astronauts may require up to six weeks of rehabilitation to regain their strength, which will include guided exercises and a tailored nutritional plan.
The effects of microgravity are compounded by the fact that astronauts often have difficulty maintaining their weight in space.e
Weight Loss
The effects of microgravity are exacerbated by astronauts’ difficulty in maintaining their weight while in space.
Frequent nausea and a loss of smell and taste due to sinus pressure lead to a decreased appetite among astronauts.
In November, doctors told DailyMail.com that Williams appeared “gaunt” in a photo taken in September, noting that she seemed to have lost weight.
Later that month, an unnamed NASA source informed the New York Post that the agency was working urgently to “stabilize the weight loss and hopefully reverse it.”
The source, who was “directly involved with the mission,” stated that Williams had struggled to keep up with the high-calorie diet astronauts must maintain 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 insider said.
However, later that month, Williams addressed the weight loss rumors in a live video published by NASA, claiming that she had actually gained muscle.
Fluid Shift
Since the body is made up of 70 percent water, this fluid shifts dramatically in low gravity.
Similar to being upside down, NASA explains that over 5.6 liters of liquid can move upwards through the body.
In some cases, this causes a condition known as “puffy face syndrome,” which leads to severe swelling of the head’s tissues.
At the same time, fluid leaving the lower body causes what NASA calls “chicken legs” and “baby feet,” where the legs appear unusually small and weakened.
Although these cosmetic issues typically resolve within about three days after returning to regular gravity, the fluid shift can also lead to serious health problems.
The upward fluid shift experienced on the ISS also increases astronauts’ risk of blood clots, specifically through a condition called Spaceflight Venous Thrombosis (SVT).
Suni Williams’ “gaunt” appearance raised concerns that she might be experiencing severe weight loss. However, Williams insists that the change in her appearance was due to fluid shifting into her face in microgravity.
Months spent in low gravity cause fluid shifts in the body, leading to health issues ranging from “chicken legs” to vision loss.
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 were also exposed to extreme levels of space radiation during their extended ISS mission.
In just one week aboard the ISS, astronauts receive the equivalent of one year’s worth of radiation exposure on Earth.
The radiation astronauts face in space is far more dangerous than the common sources of radiation on Earth.
Space radiation consists of atoms whose electrons have been stripped away as they accelerate to nearly the speed of light.
Astronauts also contend with particles ejected from the sun during solar flares, as well as galactic cosmic rays—high-energy protons and heavy ions from outside our solar system.
When these particles collide with astronauts’ bodies, they damage the DNA in our cells, triggering mutations that can lead to cancer.
While in space, astronauts experience heightened exposure to dangerous space radiation, which means that Butch Wilmore (pictured) now faces a significantly higher risk of developing cancer.
This increased exposure may raise their risk of developing cancer, central nervous system damage, bone loss, and certain cardiovascular diseases, according to NASA.
“If I were their physician, I would consider a more proactive approach to cancer screening,” said Dr. Gupta.
“We need to take a different strategy here, given their unique exposure history,” he added.
Heart Health
It’s not just their muscles and bones that take a hit—low gravity also affects their cardiovascular health.
Blood and other bodily fluids shift upwards towards the head, reducing the workload on the cardiovascular system to maintain blood flow to the brain.
As a result, this can lead to reduced blood volume and decreased function of the heart and blood vessels, according to NASA.
Skin Problems
Despite leaving Earth in good condition, NASA’s astronauts now require months of health checks and rehabilitation to recover.
Studies have shown that spending six months aboard the ISS can significantly affect the skin.
One team of researchers discovered that astronauts’ epidermis thins by nearly 20 percent in space, possibly due to low gravity, which may disrupt the skin’s ability to grow and repair itself.
Another study found that skin rashes are the most commonly reported clinical symptom during six-month ISS missions, occurring 25 percent more often than in the general U.S. population on Earth.
These rashes could be caused by irritants or allergens inside the space station, as well as the weakening effect 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 astronauts recover from these long-term effects, NASA has a specialized rehabilitation program for those returning from space.
Examinations begin immediately after they exit the capsule, followed by transport to their crew quarters at NASA’s Johnson Space Center in Houston for additional routine health checks.
NASA astronauts returning from extended ISS missions undergo a 45-day rehabilitation program, which includes two hours of exercise per day, seven days a week.
To maintain their strength, astronauts exercise for at least two hours a day on the ISS. Pictured: Sunita Williams using the space station’s stationary bike during her 2012 mission.
The rehabilitation program is customized to address the specific needs of each astronaut, according to NASA.
Phase One
Phase one of NASA’s post-mission rehabilitation plan focuses on rebuilding strength, flexibility, and the ability to walk.
This phase may include gait training exercises, range-of-motion activities, and obstacle training.
Gait training exercises aim to improve strength, balance, and coordination while walking. Examples include squats, straight leg raises, standing on one leg, and seated marching.
To enhance their range of motion, astronauts may perform ankle pumps, which involve sitting or lying down while flexing their feet. Stretching exercises for the calves, quadriceps, and hamstrings are also included.
Astronauts may also navigate obstacle courses or practice stepping over and around objects to improve coordination.
Phase Two
Sunita Williams runs on the ISS treadmill during her 2012 mission.
After making progress in phase one, astronauts move on to phase two, which incorporates proprioceptive exercises and cardio reconditioning.
Proprioceptive exercises enhance the body’s strength while improving the mind’s ability to perceive its movement and position.
Examples include reverse lunges, banded toe taps, and sumo squats with leg raises.
Some exercises are more complex. For instance, astronauts may be asked to pick up an object from the floor while standing on one leg, requiring them to hinge at the waist and maintain their balance while bending down.
For cardio training, astronauts may use a treadmill, elliptical, or stationary bike to restore their endurance to pre-flight levels.
Phase Three
Phase three, the longest phase, focuses on helping astronauts return to their optimal physical performance through functional development training.
This training is designed to help astronauts regain the skills and abilities necessary to perform their duties and fully engage in daily activities with ease and efficiency.
NASA astronaut Raja Chari carries out strengthening exercises after returning from a 177-day mission aboard the ISS.
It may incorporate higher-intensity exercises like jump squats, jump lunges, mountain climbers, planks, and deadlifts.
According to NASA, most astronauts regain their pre-mission fitness level within 45 days.
However, full recovery can take months or even years for some, and research indicates that many astronauts never completely restore their bone density.
Dr. John Jaquish, a biomedical engineer, told the Daily Mail that astronauts could potentially regain their pre-flight bone density through osteogenic loading, though it would be challenging.
This method involves exercises that strengthen bones by applying stress, such as squats, lunges, or jumping.
However, to effectively stimulate bone growth, astronauts’ bones must endure a load 4.2 times their body weight, Dr. Jaquish explained.
“For context, the world record for a squat is only four times body weight, meaning the minimum required load exceeds what even record-holding lifters can achieve,” he said.
