Drifting in freefall for months on end, our bodies adjust in ways that create a long list of health concerns for astronauts.
The latest assessment of microgravity’s combat effect on our biology focuses on the spaces around the blood vessels that weave through our brains, related to changes that accompany astronauts between missions.
Researchers across the US compared a series of magnetic resonance image (MRI) scans of the brains of 15 astronauts taken before their six-month stay on the International Space Station and six months after their return.
Using algorithms to carefully assess the size of the perivascular space (gaps in brain tissue thought to facilitate fluid balance), the team found that time spent in orbit had a profound effect on the brain’s plumbing. fell. For first-timers, at least.
In the pool of experienced astronauts, two scans taken before the mission and four taken after the mission showed little difference in the size of the perivascular space.
“Veteran astronauts must have reached some kind of homeostasis,” says neurologist Juan Piantino of Oregon Health and Science University.
The findings might not be surprising given that we already know how the brain deforms when the constant tug of gravity is canceled out.
Previous studies on brain tissue and their fluid volume have found that they are slow to recover from a stint in space, with some changes persisting for a year or more.
Right now, astronauts rarely make more than a few trips into space in their lifetime, usually circling for about six months at a time. Yet as the commercialization of the space industry accelerates, all of this could change.
It would pay to know whether repeated trips compound harm, or if the changes experienced on that first trip temporarily adapt the astronauts to a new kind of normal.
“We all adapted to use gravity in our favor,” Piantino says.
“Nature didn’t put our mind in our feet — it elevates them. Once you remove gravity from the equation, what does it do to human physiology?”
Even in the context of enlarged perivascular spaces, it is not yet completely clear whether the change comes with any significant health risks.
We make the most of this neurological drainage system when we sleep. The flow of fluids around our grays appears to play an important role in removing waste products that accumulate during our more active hours.
Without these channels working efficiently, disruptive material can accumulate, potentially contributing to an increased risk of neurodegenerative disorders such as Alzheimer’s.
It is too early to tell whether microgravity has any effect on the circulation of cerebral spinal fluid around our noggins, let alone if the change in the shape of the network of channels is significant. This may not be clear until researchers have a good-sized sample of veteran astronauts who have a substantial career under their belts.
Knowing more about these small adjustments goes beyond the potential pitfalls of working out of the world in a space industry.
“It also forces you to think about some of the most fundamental questions of science and the evolution of life on Earth,” Piantino says.
The ever-present pull of gravity just isn’t something we fight against. It is a power that we have evolved to use, to aid in the flow of blood and waste, and potentially many other functions we have hardly considered.
By studying the subtle changes in health and anatomy we’ve never evolved to tolerate, we’re almost certain to learn more about the diseases and disorders our bodies are forcing to weather here. .
This research was published in scientific report,