Space anemia affects all astronauts. This phenomenon can have long-term consequences, even when they are on land. Explanations.
- Scientists don’t know how long you can live with space anemia.
- An adapted diet, aimed at improving the cardiovascular health of astronauts, could help them fight against space anemia.
Before flying to the International Space Station, Thomas Pesquet and his other fellow astronauts underwent shock physical training for months. The reason is simple: traveling in space is a test for the body. Participants lose muscle mass in particular.
Three million red blood cells lost per second
According to a new study published in the journal NatureMedicine, an astronaut loses three million red blood cells per second in space. This phenomenon, called “space anemia”, would be responsible for the destruction of 54% of cells in the human body. “Since the first missions, space anemia has always been reported when astronauts returned to Earth, but we did not know why”, said to CNN Guy Trudel, one of the authors of the study. To discover the origin of this phenomenon, the scientists therefore studied the breath and blood analyzes of fourteen astronauts before they left for the International Space Station. Once in space and up to a year after their trip, the participants also had to carry out self-sampling.
Cardiovascular problems in space
The first lesson from these analyzes is that all the astronauts had cardiovascular problems and suffered a drop of about 10% in the blood flowing in their blood vessels. This is due to the lack of gravity causing bodily fluids to flow up the body and increasing pressure on the brain and eyes. Researchers then discovered that red blood cells were automatically destroyed when an individual was in space and their body never got used to it. In other words, an individual loses red blood cells in the same quantities throughout his journey through space.
To measure the destruction of red blood cells, the researchers first quantified the carbon monoxide detected in the astronauts’ breath samples. They thus understood the mechanism between carbon monoxide and red blood cells. Each time a molecule of red blood cells is destroyed, it is replaced by a molecule of carbon monoxide. “Fortunately, having fewer red blood cells when the body is weightless is not a problem. But when landing on Earth and potentially on other planets or moons, anemia can affect energy, stamina and strength and thus threaten mission objectives. The effects of anemia only kick in once you land and have to deal with gravity again.” explained Guy Trudel.
The impact of space anemia once on Earth
Almost all of the astronauts were diagnosed with anemia upon their return to Earth. But, little by little, their body produced red blood cells again, until it returned to the normal number. Thus, the scientists deduced that space anemia was indeed reversible, after approximately three and four months of life on Earth. Nevertheless, the rate of destruction of red blood cells by carbon monoxide remained, meanwhile, still above the average of 30%. Up to a year after the space mission, astronauts have sequelae of anemia, which means that long-duration space missions can lead to structural changes that affect red blood cells. “If we can find out exactly what is causing this anemia, then there is potential to treat or prevent it, both for astronauts and for patients here on Earth,” concluded Guy Trudel.
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