Why astronauts age faster in space

Living in space may be a once-in-a-lifetime privilege, but it could also adversely affect our bodies.

NASA shared results from its ongoing research project, Space Omics and Medical Atlas (SOMA), into the effects of living in space on astronauts’ health, revealing that spaceflight accelerates aging.

According to a paper in Scientific Reports, living in space can increase inflammation and genomic instability and cause mitochondrial dysfunction, which hastens aging.

“Spaceflight induced notable changes in gene expression patterns related to frailty and muscle loss indicative of a frailty-like condition,” NASA said. “Exposure to the space environment leads to changes related to inflammation, muscle wasting, and other age-related features observed in both mice and humans.”

This follows claims that ISS commander Sunita “Suni” Williams had lost weight to an unhealthy extent.

The astronaut stated in a recent interview that she was the same weight as before she arrived in space in June, in response to recent claims by doctors that her cheeks recently appeared “sunken.”

“I think there’s some rumors around out outside there that I’m losing weight,” Williams said in response to a question from the New England Sports Network on November 12. “I’m the same weight that I was when I got up here.”

Williams notes that she is gaining muscle due to weightlifting, part of the exercise regimen that astronauts perform while living on the ISS.

“I could definitely tell that weightlifting, which is not something that I do all the time, has definitely changed me. My thighs are a little bit bigger; my butt is a little bit bigger,” Williams said.

According to the new SOMA research, spaceflight results in “gene expression responses for DNA damage, immune activation, mitochondrial disruption, frailty, sarcopenia, accelerated health risks in multiple organs, and telomere regulation.”

Previous research found that spending an extended period in a low-gravity space environment can damage the human body.

In microgravity, muscles don’t have to work as hard to support the body, so they can weaken over time. Bones also lose density, increasing the risk of fractures. Astronauts perform daily exercises to counter these effects, but full recovery often takes time once they return to Earth.

“Astronauts experience accelerated bone loss at an alarming rate—about 12 times faster than severe osteoporosis on Earth,” Kyle Zagrodzky, founder and CEO of bone health clinic OsteoStrong, previously told Newsweek. “This rapid deterioration occurs because bones no longer bear the constant gravity load in space. As a result, density and strength diminish quickly, compressing years of potential osteoporosis into mere months.”

“Osteoporosis increases fracture risk, often leading to life-altering injuries,” Zagrodzky said. “Hip fractures pose a grave concern, as they can strip away independence and increase mortality risk.”

In the absence of gravity, bodily fluids such as blood and lymph shift upward toward the head, leading to facial puffiness and pressure on the eyes. Over time, this can cause vision changes, known as “spaceflight-associated neuro-ocular syndrome” (SANS), and, in some cases, lasting eyesight problems.

“Folks in space, their heads look a little bit bigger because the fluid evens out along the body,” Williams said.

Space also has much higher levels of cosmic radiation than Earth. Prolonged exposure on the ISS, where astronauts are partially shielded by Earth’s magnetosphere, still carries risks of increased cancer rates, nervous system damage, and other radiation-related health issues.

Williams and fellow astronaut Barry “Butch” Wilmore have been stuck on the ISS since June after the Boeing Starliner spacecraft that brought them to the station malfunctioned.

The pair were initially supposed to spend only around a week on the ISS, but after the Starliner developed thruster issues and helium leaks, the spacecraft returned to Earth without them, leaving them aboard the ISS without a way to get home. Since arriving on the ISS on June 6, they have been in space for 165 days.

Williams and Wilmore are now scheduled to return to Earth in February 2025 in the Crew-9 mission Dragon capsule, which brought NASA astronaut Nick Hague and Roscosmos cosmonaut Aleksandr Gorbunov to the ISS at the end of September. Two seats were left free to ferry the stranded astronauts home.

By the time they return to solid ground, they will have been in space for around 250 days.

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References

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