Being in space causes the human body to kill 50% more red blood cells, resulting in anemia, a potentially deadly condition. According to a new study, the benefits last long after astronauts return to Earth.

The study looked at breath and blood samples from 14 astronauts before, during, and after their six-month missions aboard the International Space Station, and was headed by experts from the Ottawa Hospital and the University of Ottawa in Ontario, Canada. The astronauts' bodies destroyed 54 percent more red blood cells than they would on Earth, according to the study.

This occurrence, known as space anemia, was already known to scientists, but they expected it to fade away over time as astronauts' bodies adapted to the space environment. For the first time, a new study has proven that this is not the case, a revelation that could have major ramifications for long-term space flight.

"Our study shows that upon arriving in space, more red blood cells are destroyed, and this continues for the entire duration of the astronaut's mission," Guy Trudel, a professor of medicine, surgery and biochemistry at the University of Ottawa and lead author of the study said in a statement.

Every second on Earth, the human body produces and kills 2 million red blood cells. The astronauts' bodies aboard the International Space Station, on the other hand, were killing closer to 3 million blood cells per second. Both male and female astronauts had the same outcomes.

Five of the 13 astronauts in the study were clinically anemic after returning to Earth; the levels of red blood cells in their blood, as well as the oxygen-carrying component hemoglobin, had plummeted to such low levels that other tissues in their bodies were not receiving enough oxygen. Anemia is known to produce weariness, physical weakness, and dizziness, all of which could be dangerous for astronauts who routinely perform difficult tasks requiring concentration, precision, and physical fitness.

Following that, after three or four months back on Earth, the red blood cell levels of the astronauts in question restored to normal. However, even after that time, their bodies were eliminating roughly 30% more red blood cells than before they travelled to space, indicating that space flight had long-term effects.

Fortunately, none of the astronauts in the study experienced any symptoms of anemia while in space. As a result, the researchers believe that the astronauts' bodies continued to produce new blood cells throughout their missions. However, enhanced red blood cell formation necessitates specific nutrients, therefore future astronauts' diets should reflect this, according to the researchers. This is especially critical for long-duration missions, which can lead to more severe anemia, according to a prior study.

Research into space anemia could someday aid people who acquire anemia after being bedridden due to an injury or a long illness, in addition to helping astronauts stay healthy in space. Scientists don't fully understand why being bedridden causes the body to destroy red blood cells, just as they don't fully understand why space anemia occurs.

"If we can find out exactly what's causing this anemia, then there is a potential to treat it or prevent it, both for astronauts and for patients here on Earth," Trudel said.

The study is the first to come out of the Canadian Space Agency's MARROW project, which is looking at the impacts of space on human bone marrow and blood cells.

The study was published in the journal Nature Medicine on Friday (Jan. 14).