ISS astronauts suffer decades worth of bone density loss in few months, new study finds

Astronauts exposed to micro-gravity for months at a stretch encounter severe loss of bone density and do not recover even a year after their space mission, new research has warned. Published in Scientific Reports, the research is based on observations of bone loss in astronauts who were on long-duration missions aboard the International Space Station (ISS). The findings were disturbing as the researchers found decades' worth of bone loss in astronauts with very little recovery even after a year back on Earth.

Study reveals disturbing results 

Led by kinesiologists Leigh Gabel and Steven Boyd from the University of Calgary, the research involved the study of 17 astronauts,14 men and three women who had been on long-term space missions (four to seven months) in the past seven years. To measure the effects of micro-gravity on these astronauts, Gabel and Boyd evaluated their wrists and ankles before and twice (at six and 12 months) after their return to Earth. 

Surprisingly, the experts found that the bone loss encountered by some astronauts in just a few months was equivalent to what they would have experienced in a decade on Earth. Moreover, loss of shin bones in some of the candidates had not fully recovered even after spending a year on Earth following their mission. 

'Big concern' for long-term space missions

One of the study authors, Boyd, called this a "big concern" as the rapid loss of bone density would prove to be a major hurdle in planetary explorations of the Moon and Mars. Notably, previous studies have suggested that astronauts lose 1-2% of bone density for every month they spend in space and according to Boyd, he doesn't know if this would get better or worse.

While astronauts aboard the ISS resort to two hours of daily exercise to preserve their bones, the same would not suffice for the crew on missions to Mars, which would take at least nine months for a one-way journey. "Even with two hours of sport a day, it is like you are bedridden for the other 22 hours", Guillemette Gauquelin-Koch, the head of medical research at France’s CNES space agency, who was not part of the research said, as per The Guardian. "It will not be easy for the crew to set foot on Martian soil when they arrive, it’s very disabling," Gauquelin-Koch added. 

However, scientists are currently working to address this issue, an example of which is the European Space Agency's (ESA) 3D printing of artificial bones for emergency situations. Tap here to read more about it.