Scientists have known for a long time that life in outer space has a detrimental effect on astronauts' physique. One of them, makes them suffer from anemia.
Since the first space mission, astronaut crews have returned to Earth with anemia, a condition where the body lacks enough red blood cells to carry oxygen to body tissues.
Health experts are confused as to how this happened. But a new study published in the scientific journal Nature and funded by Canada's national space agency, CSA, reveals a mechanism that contributes to this potentially dangerous condition.
Quoted from Pop Science, of the more than 35 trillion red blood cells in a healthy adult human body, at least 2 million of them are created and hemolyzed or destroyed every second.
But in space, about 3 million red blood cells are destroyed every second, causing astronauts to lose about 54% more blood cells than when they were on Earth.
"Therefore, when astronauts return to Earth, they will be treated like injured people. We wanted to know how quickly they recovered, and how complete the recovery was," said study lead author Guy Trudel, a rehabilitation physician and researcher at Ottawa Hospital and professor at the University of Ottawa.
Long term anemia
Initially, this anemia was thought to be temporary as it is characterized by a 10 to 12% decrease in red blood cell count during the astronaut's first 10 days in space. At that time, body fluids shift to adjust.
But Trudel's research reveals that this process doesn't stop in space. Anemia actually continued for the next six months.
Trudel and his team first demonstrated the causes of anemia in space, but created a different method from previous studies, which analyzed blood samples and radioactive injections. Instead, his team analyzed breath and blood samples.
"Merely drawing blood is not enough to know about the destruction of blood cells, and that's why this knowledge was hidden for so long," he said.
Between 2015 and 2020, samples were collected from 14 astronauts (11 men and 3 women) before they left Earth, during their stay on the International Space Station (ISS), and again when they returned to Earth.
Trudel's team measured the concentration of carbon monoxide molecules left in the astronaut's breath as blood degraded, indicating an increase in the breakdown of red blood cells in the body.
They found that this destruction, or hemolysis, was the main effect of microgravity, suggesting that the anemia was caused by the astronaut's environment.
Although specimens were collected from astronauts on a six-month mission, the researchers reasoned that longer space missions could lead to more severe anemia.
Nearly 25% of the population already has some form of anemia, according to the World Health Organization. This latest discovery could be used to enforce stricter health requirements for astronauts assigned to longer manned missions, and individuals interested in signing up for space tourism.
