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Illustration image. Source: new-science.ru
Due to the reduction of weight, the muscles responsible for interlocking the vertebrae weaken, causing the muscles to gradually contract and the natural curvature of the spine to diminish. These are just a few factors affecting the physical condition of astronauts.
To mitigate these effects, astronauts aboard the space station often don a special “Penguin” suit. This suit helps tone the muscles and creates a load for the musculoskeletal system through specially designed vibration-damping equipment.
During their time in space, astronauts typically grow an average of about 3-5 cm taller. This presents certain challenges for them. Specifically, to return them to Earth, the landing module is equipped with seats meticulously adjusted to each astronaut’s increased height.
The incompatibility of seat size with body height can jeopardize the safety of astronauts. In an interview with Russia’s “Rossiyskaya Gazeta,” Russian politician Valery Bogomolov revealed that aerospace engineer Anatoly Ivanishin on the International Space Station (ISS-30) had to hurriedly accommodate his increased height. And this wasn’t an isolated incident.
Weightlessness also affects the aging process of the body. A study published in “The FASEB Journal” in August 2020 revealed that rapid aging in weightless conditions is not related to processes occurring in the musculoskeletal system but rather to the cellular level. These cells line the inner walls of blood vessels throughout the body while forming an anti-coagulation membrane. All of this has a direct impact on the human cardiovascular system.
Editor-in-chief of “The FASEB Journal,” Gerald Weismann, noted that humans evolved in conditions of gravity to regulate biological processes. Without gravity, tissues disappear and age rapidly.
The weightless environment negatively impacts bone density, as bones lose calcium and gradually weaken. After living in weightlessness for a month, an astronaut’s bone mass can decrease by 1-2%. This is due to disruptions in phosphorus metabolism and the body’s suspension of bone-building materials. This phenomenon is known as space osteoporosis.
Furthermore, excess calcium in the blood can adversely affect kidney function. Fortunately, upon returning to Earth, astronauts regain bone mass. However, prolonged exposure to weightlessness can have the worst impact on human health. Thus, during a 3-year journey to Mars, astronauts might lose up to 50% of their bone mass, making it impossible to return to Earth and recover.
Speaking of muscle atrophy in space, it’s crucial to mention the body’s main muscle: the heart. Furthermore, not too long ago, the National Aeronautics and Space Administration (NASA) conducted an intriguing study. As it turns out, the heart not only weakens and loses volume but also becomes more rounded. During the study, NASA’s cardiologists examined the hearts of 12 astronauts who had worked on the International Space Station. Analysis of the images showed that in a weightless environment, their hearts became 9.4% rounder.
However, after returning to Earth, within half a year, the heart returns to its normal shape and restores its functions under Earth’s conditions. To understand the extent of heart function decline, consider that just lying in bed for 1.5 months is equivalent to a week’s work in weightless conditions on orbit.