Article by: Andacs Robert Eugen, on 02 July 2022, at 07:14 am Los Angeles time

Scientists from NASA, Germany, and Canada have found that the bone density of many participants in long-term expeditions to the ISS decreases rapidly during life in weightlessness and does not return to normal even a year after returning to Earth.

Researchers have been studying the effects of living in space on health and immunity for years. For example, a few years ago, scientists discovered that long space flights weaken the back muscles and lead to a rounding of the heart.

Animal experiments have also shown that a flight to Mars can negatively affect people's psyche and mental abilities.

Scientists have noticed that they have known about the decrease in bone density since the first flights into space. However, its rate of recovery on return to Earth has not been disclosed.

For this reason, they studied the tibia tomograms of 17 astronauts and tracked changes in bone condition during long flights to the ISS. The researchers compared CT scans before a flight, immediately after returning from space, and 6 and 12 months later.

Measurements showed that the tibia density in about half of the astronauts did not return to pre-flight values ​​even a year after they returned to Earth and completed the rehabilitation program. On average, the indicator decreased by 0.9-2.1%.

"Our observations have shown that the bone density of astronauts has only partially recovered one year after their return to Earth. This suggests that long-term spaceflight leads to an irreversible decrease in bone density, which is the equivalent of sudden 10-year aging," said Lee Geibel, an associate professor at the University of Calgary (Canada).

The largest reductions in bone mass were among those astronauts who spent more than six months aboard the station. Their bone tissue recovered after returning to Earth much harder than that of the astronauts, who spent less time on board. The changes were reflected throughout the skeleton.

According to researchers, irreversible changes in bone tissue due to long spaceflight should be considered when developing exercise sets for astronauts.