Long-term observations of the health of the ISS crew have shown that life in space does not lead to the development of anemia and other problems with the circulatory system, which could make a trip to Mars dangerous for astronauts' health, according to an article published in the journal BMC Hematology.
“If astronauts go on expeditions to the surface of the Moon or Mars, if they have to leave the spacecraft and there are not enough red blood cells in their blood, then they will feel very tired and exhausted. They must be in perfect shape to make such forays and explore the surface of new worlds,”said Kathleen McMonigal of NASA Johnson Space Flight Center (USA).
For many years now, Russian and American scientists have been studying how life in space affects human health and the functioning of the immune system of humans and animals. For example, in 2015, they found out why many astronauts complain of vision problems in space, as well as why the Apollo astronauts periodically fell and lost their balance on the moon.
Last year, space physicians uncovered even more disturbing changes in the way humans and model animals function while living in space. In particular, it turned out that a prolonged stay in zero gravity irreversibly weakens the muscles of the back and leads to "rounding" of the heart, and a flight to Mars can lead to a noticeable deterioration in the intellectual abilities of astronauts due to the destructive effect of cosmic rays on their brains.
McMonigal and her colleagues studied data collected by American physicians from observations of the health of astronauts who made relatively short flights into space aboard the shuttles in the early and late 2000s, which lasted for several days or approximately two weeks.
Blood samples obtained from astronauts immediately after leaving the spacecraft indicated an alarming trend - in just a few days spent in space, the mass of their erythrocytes, red blood cells, fell by 10-15%, and the volume of plasma decreased by 17%. Both, as the doctors believed then, should lead to the development of anemia during longer flights into space.
NASA scientists have checked whether this is actually the case by observing the health of the ISS crew members who spent at least six months on board the station. By comparing their blood samples before, during and after the flight into space, biologists hoped to understand how serious the differences in red blood cell size and plasma composition were, and to find out if they could be eliminated.
A total of 31 ISS crew members took part in this project, most of whom were brought aboard the station by Russian Soyuz. As it turned out, none of them suffered from the problems that were recorded among the crew members of the "shuttles" who made short-term flights into space.
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In the first days after getting on board the station, the mass of erythrocytes, the volume of plasma and other properties of the blood did deteriorate, but then they stabilized and did not change for many weeks and months. This, according to McMonigal and her colleagues, suggests that anemia will not be one of the main problems for future marsonauts or base inhabitants in orbit of the moon.
