Multiple changes occur in the human organism when staying in outer space, among them illusions or errors of perception with the environment, inability to tilt the head, sudden vomiting, loss of bone mass, increase in height, and swelling of the face, for example.
Aerospace Medicine is a medical branch that focuses on the clinical and scientific study of people's bodies in one of the most hostile environments that can be faced: space. In recent years there has been a boom in space activity, which has not been seen since the 1960s and 1970s, and in which even private companies are participating, seeking to achieve new trips, such as taking humans to the Moon and having a station on Mars.
In these transfers, the body needs spacesuits equipped with high technology that serve as individual ships, focused on the protection and maintenance of human conditions as if they were on Earth. Thus they face, for example, radiation and gravity. These drastic alterations in organisms also have adaptation processes when returning to Earth, after the first moment in a microgravity environment or exposed to cosmic radiation.
Some of them are tangible, for example, two twins were compared, one of them was in the International Space Station, and on his return, he was almost four centimeters taller, something that gravity was in charge of putting back in its place. The state of weightlessness has effects on the body, for example on the nervous system composed of the brain, spinal cord, and peripheral nerves.
In space, the nervous system undergoes some changes due to radiation, lack of gravity, and extreme temperatures, and suffers from Space Pressure Syndrome, the process the body has to go through to get used to the space environment. It can be identified by experiencing headaches, stomachaches, dizziness, nausea, inability to tilt the head, and sudden vomiting for up to seven days.
There are also illusions or errors of perception with the environment, such as feeling that one is the floor, that one is going sideways or floating; postural errors when the astronaut leaves orbit and there is the inability to be fully upright. In microgravity, our cardiovascular system, consisting of the heart and blood vessels, is going to remodel itself so that all the blood can reach the entire body and continue to function as it should to keep us alive.
In a state of microgravity, blood and all body fluids go from the legs and abdomen to the heart and head, which causes astronauts' faces to swell, the heart to be overloaded and the pressure in the blood vessels to increase. Regarding the skeletal system, travelers experience weakening of the bones due to loss of bone mass, which predominates in the lower-middle part of the body. Astronauts may lose one to two percent of their total bone mass, causing calcium that is not in the bones to go into the blood and accumulate in the kidney.