spaceSpace and Physics

The Blood Of Cosmonauts Show The Effect Of Space Travel On The Human Body


Tom Hale

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist

Russian cosmonaut Oleg Kotov does a space walk off the International Space Station on August 18, 2014. NASA Johnson/NASA

As fleshy Earth-dwelling mammals, you might assume our bodies are not particularly well prepared for life outside the cozy atmosphere of our planet. But if space exploration is something we are going to take seriously as a species, we need to find out how well the body copes with these less-than-usual conditions. 

A team of Russian scientists analyzed the blood of 18 space-faring cosmonauts to find out how it affects their health. The results were recently published in the journal Nature Scientific Reports.


Effectively, weightlessness and the other strange conditions of space bewilder the body. In the researcher's own words, “the human body doesn't know what to do,” so it kicks the immune system into hyperdrive and bolsters up its defenses, just like it would if it came across a nasty infection.

Scientists have been studying the effects of space travel ever since the early days of the Space Race. So far, they have found out a fair amount about the effects of space travel on metabolism, thermoregulation, heart biorhythms, muscles, etc. Now, they took a look at how it affects humans on a molecular level.

They searched for 125 proteins in the blood plasma of 18 Russian cosmonauts who had taken part on long missions to the International Space Station (ISS). They took samples 30 days before their mission, immediately after they returned to Earth, and once more seven days after their landing.

"For the research, we took a set of proteins – non-infectious diseases biomarkers," lead author Professor Evgeny Nikolaev, from the Moscow Institute of Physics and Technology, said in a statement. "The results showed that in weightlessness, the immune system acts like it does when the body is infected because the human body doesn't know what to do and tries to turn on all possible defense systems."


Concentrations of some of the proteins remained unchanged by spaceflight, some quickly bounced back after returning to Earth, while others took a long time to return to their previous concentrations. Of the 125 proteins, 19 were influenced by space flight.

"Plasma proteins whose concentrations changed during flight included pathways related to oxidative stress, cytoskeleton, cell proliferation, glucose and lipid metabolism, cell damage and repair response, apoptosis, calcium/collagene metabolism, transport of lipoproteins, cellular functions, protein degradation, signal transduction and cell energy metabolism," the team wrote in their study.

Next up, the team hope to have cosmonauts take blood tests while in orbit to detect more specific proteins.

One of the most ambitious studies to look at the effects of space travel on the body was NASA’s recent “Twin Study”. Scott Kelly spent a year on the ISS, while his identical twin brother Mark remained on Earth. Once back home on Earth, they compared the genetic differences between the two. You can read more about the discoveries from the Twin Study here and here.


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