Space travel is not as safe for humans as we would like it to be. Scientists are reminding us of that now. They have studied the effect it can have on the blood of astronauts. And they confirm the serious reality that is space anemia syndrome.
Astronaut
We already know that astronauts get taller in space, but now we can also add to it that space travel destroys our red blood cells. To an impressive degree. It’s even a primary trait, according to researchers at the University of Ottawa. This is the conclusion they draw from a six-month study of 14 astronauts on a mission to the International Space Station (ISS) and the composition of their blood.
Recall that our body on Earth produces and destroys no less than 2 million red blood cells every second. During the time spent in space, men’s and women’s bodies destroy 54% more red blood cells. That’s just over 3 million per second. This explains the long-known space anemia syndrome.
Although they haven’t measured it, researchers imagine that astronauts also produce more red blood cells to replace those on Earth. Otherwise, they risk severe anemia and serious health problems. They also note that the lack of red blood cells has little effect while the body is in zero gravity. But the effects of anemia tend to catch up with astronauts when back on Earth.
Research also shows that red blood cell levels generally return to normal three to four months after returning to Earth. Even a year later, astronauts’ bodies are still destroying more red blood cells than before their stay in space. Up to 30 percent more, in fact. That suggests structural changes. And it raises other questions, like what impact it has on astronauts’ diets, or how long the body can maintain this rate for long missions to Mars.
This work may also shed light on patients who become anemic after prolonged bed rest. Doctors don’t understand the mechanism. A mechanism that may be similar to the one that leads to space anemia.
References
Trudel, G., Shahin, N., Ramsay, T. et al. Hemolysis contributes to anemia during long-duration space flight. Nat Med 28, 59–62 (2022). https://doi.org/10.1038/s41591-021-01637-7
