After returning from the International Space Station (ISS), astronauts return to Earth up to six centimeters taller than before they left, but this change is temporary and is accompanied by a more demanding process of organism recovery.
The increase in height occurs due to the absence of gravity, which on Earth constantly presses on the spinal column. In space, this pressure is removed, so the spine temporarily “elongates”.
The spine is relieved of pressure in space
On Earth, body weight constantly acts on the spine, so the vertebrae and intervertebral discs are under pressure. This is why people are slightly taller in the morning than in the evening.
U bestežinskim uslovima, kakvi vladaju na ISS-u, taj pritisak nestaje. The spine then relaxes and its temporary elongation occurs, which can “give” astronauts up to six centimeters of additional height.
Changes are not only in discs
Although it was previously thought that the main cause was the expansion of the discs between the vertebrae, research has shown that the paraspinal muscles also play a significant role. They relax in microgravity in a way that is not possible on Earth, which further contributes to the change in height.
Temporary effect, but long-term recovery
The increase in height is transient and usually disappears within a few days or weeks after returning to Earth. However, the changes in the organism that occur during a stay in space are more serious.
Astronauts can lose between 1 and 1.5 percent of bone density in weight-bearing parts of the body, while the muscles and spine undergo adjustments that do not recover immediately.
What affects the long-term consequences
Longer space missions, such as a potential trip to Mars, would further increase these physiological changes and prolong recovery after return.
Changes in astronaut height also affect the practical aspects of space missions, including the design of spacesuits, seats and cabin space, which must be adapted to possible variations in body dimensions.
What at first glance seems like an interesting “bonus” at altitude, is actually an indicator of how hard the human body tolerates conditions without gravity and how complex the recovery is after returning to Earth.
(Flash/N1)
