Astronauts Found to Destroy 54% More Red Blood Cells in Space

A study found the dangers posed by spaceflight and the impacts on red blood counts for Astronauts on long-duration missions. The research deepens our knowledge around a condition known as “space anemia” and has important implications for the future of space exploration.The lead author said that space anemia has consistently been reported when Astronauts returned to Earth since the first space missions, but we didn’t know why. The study shows that upon arriving in space, more red blood cells are destroyed, and this continues for the entire duration of the mission.

Space anemia had been considered a short-term, fleeting condition resulting from the body’s adaptation to the space environment, with fluids shifting toward the upper body upon arrival due to the lack of gravity. This causes them to lose 10% of the liquid in their blood vessels, and it had been assumed that their body swiftly destroys 10% of red blood cells to keep things in check, with the blood cells replenished to normal levels after ten days space.

This revealed that the Astronauts destroyed three million red blood cells every second during their six-month stay on the International Space Station. This is 54% more than the two million our bodies destroy and replace every second on Earth, with the effects observed in both male and female. While direct measurements of red blood cell production weren’t taken. The team assumes the lost cells were quickly replaced. Otherwise  the Astronauts would have developed severe anemia.

The results suggest that Astronauts or space tourists should be screened for conditions that might be affected by anemia, and diets may need to be adjusted to account for the extra red blood cell loss. Importantly, it is also unknown how long the body can sustain this higher destruction and production rate of red blood cells, and the scientists are yet to determine the exact biological mechanisms behind it.