THURSDAY, Aug. 4, 2022 (HealthDay News) — Astronauts could spend weeks or months in space, where their bones could be lost for years.
The research team from Germany, the United States and Canada studied 14 men and 3 women before spaceflight and at 6 and 12 months after their return. They measured the density and strength of the tibia and lower arm bones, as well as the tibia and radius. They also measured the trabecular microstructure within the bone.
Bone turnover — the assimilation of old bone and the replacement of new bone — was also measured using biomarkers in the astronauts’ blood and urine.
The results are worrying, the researchers said.
Nine of the 17 astronauts returned from space without a full recovery for a full year. Their bone strength and mineral density decreased by 2%.
“This may not sound like much, but it corresponds to at least a decade of age-related bone loss,” said study author Anna-Maria Liphardt, an exercise scientist at the University Hospital Erlangen in Germany.
“For those affected, this means they will have to develop osteoporosis and fracture susceptibility earlier,” she said in a hospital news release.
How bones age Bone aging in space appears to be different from bone on Earth.In space, the internal structure of an astronaut’s bone is more affected than periosteum, the outer sheath supplies the bones with blood, nerves and cells that help them grow and heal. Some astronauts suffered irreparable damage, the study found.
“We were able to show that the longer the astronauts were in space, the more difficult it was to regenerate,” Liphart said.
“Bone turnover is the process by which cells break down and form new cells,” Liphardt said. “People with higher activity levels have higher rates of bone turnover, and the challenge is to maintain these activity levels during space missions.”
The discovery could be relevant for future spaceflights to Mars.
“If humans are in space for three years at a time, we also need to pay close attention to the health risks involved,” Liphart said. “Today this already applies to missions where astronauts typically spend no more than six months in zero-gravity conditions.”
The solution could be tweaking training and adding medication for those heading to space.
Research shows that the International Space Station has treadmills, exercise bikes and weight training programs, but it is critical to adjust training programs during spaceflight to better meet the individual needs of astronauts.
“Developing new sports gear that works in zero gravity without taking up too much space is especially challenging,” Liphardt said.
Medications, such as bisphosphonates, prevent bone degeneration and are used as Osteoporosis Treatment may also help.
“NASA has used bisphosphonates, but we don’t know enough about exactly how they work in microgravity,” Liphart said. “We recommend further systematic studies on the combination of drug therapy and physical exercise.”
The findings may also help people on Earth with chronic diseases. Some can cause muscle and bone loss due to lack of activity.
Source: Friedrich-Alexander-Erlangen-Nuremberg University Hospital, press release, 29 July 2022