NASA Astronauts on Space Station Suffer Horrific Amounts of Bone Loss, Study Finds

Space missions are slated to launch in the coming decades. Not only does NASA plan to return to the moon with the Artemis missions, but the agency and a number of private space companies like SpaceX have made it their goal to colonize Mars. However, as we enter the dawn of a new space age, little is known about the impact of long-term space travel on humans. But some new research is shedding light on how months of microgravity affect the body — and it’s not looking good.

In a study published Thursday in Scientific Reports, University of Calgary Researchers have found that astronauts who spent more than three months in space aboard the International Space Station (ISS) only partially recovered from severe bone loss. While the phenomenon occurs naturally in humans on Earth, the loss appears to be more pronounced when the body is exposed to microgravity. In fact, the study authors found that six months in space led to this decades worth bone loss.

“It’s incredibly rare to understand what happens to astronauts and how they recover,” said Leigh Gabel, an assistant professor of kinesiology and the study’s lead author, in a press release. “This allows us to look at the processes that take place in the body in such a short time. We’d have to follow someone for decades on Earth to see the same amount of bone loss.”

The problem arises from the microgravity environment of space. One of the biggest factors affecting bone health is weight. Like muscles, bones need weight and stressors to maintain their strength. Without them, they will weaken over time. If your body is too underweight, it can lead to serious bone problems, including osteoporosis, a disease that causes your bones to become so fragile that even a fit of coughing can result in cracked ribs.

So it makes sense that the microgravity environment of the ISS would result in significant bone degradation over time. However, the study authors say the level of loss and recovery varies from astronaut to astronaut.

“We’ve seen astronauts struggling to walk after returning from space due to weakness and balance issues, and others happily riding their bikes around the Johnson Space Center campus to meet us for a study visit. There’s a whole range of reactions among astronauts when they return to Earth,” said Steven Boyd, director of the McCaig Institute for Bone and Joint Health and co-author of the study, in the press release.

These results underscore the need for research into the effects of long-term space travel on the human body—especially as we embark on ambitious off-planet colonization missions. The study’s authors plan to build on the research and study the effects of even longer stays in space to provide insights for future astronauts.

“Astronauts will venture into space in this decade and in the coming centuries humanity will populate other star systems,” Rober Thirsk, former astronaut and Chancellor of UCalgary, said in the press release. “Now let’s push the boundaries of space exploration to make this vision possible.”