Over the last six million years, humans have been evolving as a species specifically adapted for life here on Earth.

Everything about our species – from our use of tools and our big brains, to the way we breathe oxygen and sweat for temperature regulation – is a specific adaptation to allow us to survive, as land-dwelling creatures, on our specific planet.

However, those big brains have left us wanting more. And as we reach for further frontiers in our solar system, attention has turned to how travelling beyond our home planet affects the body.

One recent study, which has produced fascinating – albeit slightly – uncomfortable results, focuses on the effects of space travel on the human brain.

The research, which was recently published in the journal Frontiers In Physiology, assessed the cognitive function of 25 professional astronauts – with results that showed a striking impact of space travel on brain function.

That’s because of the huge differences in environmental factors in space, compared to back on Earth in the environment that the astronauts’ bodies are adapted to survive in.

Not only are astronauts under the immense pressure of carrying out vital scientific research while they are in space, they are also subject to vast differences in gravity and radiation. All of this puts an extreme amount of stress on the body – and, as it turns out, the brain too.

Given our species’ ever-increasing desires to traverse the planets beyond our own, it was about time that we understood the impact on our brain health. The results of the study, which was led by Dr Sheena Dev from NASA’s Behavioral Health and Performance Laboratory, shows that the impacts on the brain are significant.

The project collected data from the 25 astronauts who had lived and worked on the International Space Station, at five stages during their journey. The astronauts carried out ten tests before their mission, and toward the beginning and end of their mission. Then, ten and thirty days after returning to Earth, they took the tests again.

The tests, which observed their speed and accuracy while undertaking the tests, demonstrated with clarity that many factors were impaired while in space, with the astronauts being slower in their responses, with their memory and attention span also affected. However, their accuracy did not change.

Given the level of precision and accuracy required for astronauts undertaking work on the ISS, this factor will allow scientists to breathe a little easier.

However, as Dev explained in a statement, we should cut the astronauts a little slack since we are often impacted in similar ways at work, even down here on Earth:

“Even on Earth, processing speed, working memory, and attention are cognitive domains that can show temporary changes when an individual is under stress. Other domains, such as memory, are less vulnerable to stressors. For example, if you happen to have a really busy day but couldn’t get much sleep the night before, you might feel like it’s hard to pay attention or that you need more time to complete tasks.”

Since astronauts often suffer from sleep disruption and the pressure of an incredibly important job – with theirs and their colleagues’ lives often in their hands – it is understandable that their cognitive function would suffer.

The good news? The impacts did not appear to be long lasting, with the astronauts’ previous levels of cognitive function restored after spending some time back on Earth, as Dev explains:

“We show that there is no evidence of any significant cognitive impairment or neurodegenerative decline in astronauts spending six months on the ISS. Living and working in space was not associated with widespread cognitive impairment that would be suggestive of significant brain damage.”

However, it is important to note that this study only extends to life aboard the International Space Station.

How our brains will respond to living on Mars, for example, is still unknown.

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