The blood problem that makes it difficult for humans to go to Mars

BBC News Brazil

Scientists have made new discoveries about why space travel causes astronauts to become anemic, sometimes for long periods, upon returning to Earth.

Canadian researchers claim that 50% more red blood cells are destroyed in space, and this continues to happen throughout the duration of the mission. As a result, long trips to the Moon, Mars and beyond — including space tourism trips — can be challenging.

At the same time, the findings could help patients hospitalized in ICUs on Earth who also suffer from anemia.

“Space anemia” has been known to scientists since the return of the first missions to Earth — but the reasons behind the medical problem were still a mystery. Now, a small study by the University of Ottawa (Canada) with 14 astronauts who spent six months on the International Space Station brings new clues.

Using blood and breath samples taken during the missions, the researchers were able to measure the intensity of red blood cell loss. These blood cells are responsible for carrying oxygen from the lungs to all parts of the body – they are therefore crucial for survival.

“Our study shows that when [astronautas] arrive in space, red blood cells are destroyed, and this continues throughout the astronaut’s mission,” said Guy Trudel, lead author of the research.

As long as the astronaut is in space, because of antigravity, this loss of blood cells is not a problem. But as soon as he returns to Earth, this translates into loss of bone mass, loss of muscle strength and a great feeling of tiredness.

Three million red blood cells are destroyed per second in space, compared to 2 million on Earth. Fortunately, the body is able to compensate for this — otherwise, astronauts would still be extremely sick during their stay in space.

But researchers aren’t sure how long the body can withstand this constant need to repair itself, especially on long-duration missions.

“Longer missions to the Moon and Mars, in addition to tourism and space commercialization, require a better understanding of space-induced anemia,” the study says, adding that monitoring people sent into space “will be vital for human missions that land in space.” on extraterrestrial soils without medical supervision”.

In addition, the study brings hypotheses about the causes: “The findings of the study suggest that the destruction of red blood cells (…) is a primary effect of microgravity on spaceflight and supports the hypothesis that space-associated anemia is a hemolytic condition that must be taken into account in the selection and monitoring of both astronauts and space tourists. (…) As humanity plans extraterrestrial travel, understanding the health implications of living in space is crucial to planning safe travel”.

PATIENTS IN ICUs

In the astronauts in the Canadian study, space anemia persisted even after a year that they had returned to Earth — that is, they continued to lose red blood cells at a faster rate than would otherwise be the case. The problem affects both men and women.

“If we can explain what exactly causes this anemia, then there is the potential to treat or prevent it, for both astronauts and patients on Earth,” says Trudel.

He believes that the anemia caused by space travel is similar to that experienced by patients who had to spend months in ICUs, with diseases such as Covid-19. Anemia makes it difficult for these patients to exercise and recover, and Trudel’s team will investigate the mechanism behind this in future studies.

Findings so far, published in the journal Nature Medicine, indicate that participants on long-duration missions or to distant planets may need to adapt their diets, including more iron and eating more calories, to boost energy levels.

Examining astronauts and tourists to identify potential problems exacerbated by anemia before flights may also be necessary, the researchers say.