A study of bone loss in 17 International Space Station astronauts reveals the effects of space flight on the body and possible remedies. This knowledge is crucial for future operations.
The research obtained fresh information on astronaut bone loss due to microgravity and bone mineral density recovery on Earth. 14 male and 3 female astronauts with an average age of 47 spent between 4 and 7 months in space, averaging 5 1/2 months.
One year after astronauts’ return, the tibia had 2.1% less bone mineral density and 1.3% less bone strength. Nine astronauts never regained bone density after their space mission.
“During long spaceflights, astronauts lose bone mass. We monitored astronauts for a year after space travel to investigate whether and how bone heals. Leigh Gabel, a University of Calgary exercise scientist, wrote the research.
Gabel remarked that “astronauts endure severe bone loss during six-month spaceflights, loss we’d anticipate in older folks over two decades on Earth,” with only about half of this loss restored after one year back on Earth.
In space, bones that normally support weight lose mass, causing bone loss. Gabel said space agencies must improve exercise and nutrition to prevent bone loss.
“During spaceflight, bone structures atrophy and rods separate. Gabel notes that although the astronaut’s surviving bone connections may grow and strengthen on Earth, those cut in space cannot be restored, permanently changing the astronaut’s bone structure.
The study’s astronauts spent seven years aboard the ISS. They were from NASA, the Canadian Space Agency, the European Space Agency, and the Japan Aerospace Exploration Agency.
As space agencies plan future missions, human resistance to spaceflight is a concern. NASA plans to return humans to the moon by 2025. This might lead to human Mars missions or prolonged lunar stays.
Gabel: “Microgravity affects muscle and bone.” The heart also changes. Without gravity to pull blood down, astronauts’ blood collects in the upper torso. This affects the heart and eyes. The further astronauts travel from Earth, the greater their radiation exposure and cancer risk.
Longer space missions increased bone loss and reduced bone regeneration. Resistance training on the ISS reduced muscle and bone loss. More deadlifts while on assignment helped astronauts rebuild bone mass. We don’t know how long-term microgravity impacts human health, says Gabel. We predict bone loss to peak during longer missions and then halt.