The human body did not evolve to handle life in space, and it shows in our very blood.
Since our species first started to spend extended periods of time beyond our planet, researchers have noticed a curious and consistent loss of red blood cells among astronauts.The phenomenon is called 'space anemia', and until recently, its cause was a mystery. Some experts have argued space anemia is only a short-term phenomenon – a brief compensation for the fluid changes in our bodies under microgravity.
The measurements were made via blood tests of iron and breath tests based on carbon monoxide. For every one molecule of carbon monoxide exhaled, a molecule of the pigment found in red blood cells is also destroyed, which makes it a useful approximation of red blood cell loss.While still firmly grounded on Earth, astronauts in the study were creating and destroying about 2 million red blood cells a second.
For years, this was the explanation for space anemia. Perhaps the loss of red blood cells was our body's way of compensating for a loss in blood volume. Even after 120 days, when all the red blood cells in an astronaut's body had been created in space, the loss of red blood cells continued at a similar pace.