Space can be an unfriendly place for the human body, with microgravity conditions and other factors messing with our physiology, from head to toe—the head, of course, being a primary concern.

A new NASA-funded study provides a deeper understanding of the problem. Astronauts traveling aboard the International Space Station (ISS) or NASA’s space shuttles on missions lasting at least six months have tested the cerebral ventricles — the spaces in the center of the brain, researchers said Thursday. which contains cerebrospinal fluid.

This colorless and watery fluid flows in and around the brain and spinal cord. It helps protect the brain from stress and removes waste products.

Based on brain scans of 30 astronauts, the researchers found that it took three years for the ventricles to fully recover after such a trip, suggesting that at least that period of time between long space missions is appropriate. Will be.

“If the ventricles don’t have enough time to recover between back-to-back missions, this can affect the brain’s ability to cope with fluid changes in microgravity. For example, if the ventricles are already “Extended from the previous mission, they may be less synchronized and/or have less room to expand and adjust to fluid shifts during the next mission,” said University of Florida neuroscientist Heather McGregor, who led the study. Lead author published in the journal Scientific Reports.

Age-related ventricular enlargement — caused not by microgravity but by cerebral atrophy — may be associated with cognitive decline.

“The effect of ventricular enlargement in astronauts is currently unknown. More long-term health follow-up is needed. This ventricular enlargement likely compresses surrounding brain tissue,” University of Florida professor of applied physiology and kinesiology. And said Rachel Sadler, senior author of the study.

The absence of Earth’s gravity alters the mind.

“It seems to be a mechanical effect,” Seidler said. “On Earth, our vascular systems have valves that prevent all of our fluids from pooling at our feet due to gravity. In microgravity, the opposite happens—fluids move toward the head. Ventricular dilatation is likely to result from the fluid shift, and the brain sits higher within the skull.”

The study involved 23 male and seven female astronauts – with an average age of around 47 – from the US, Canadian and European space agencies. Eight traveled on nearly two-week space shuttle missions. Eighteen were on ISS missions of approximately six months and four were on ISS missions of approximately one year.

There was little change in ventricular volume in astronauts after short missions. Astronauts increased after missions of six months or longer, although there was no difference among those who flew for six months compared to those who flew for a year.

“This suggests that the majority of ventricle expansion occurs during the first six months in space, then begins to decrease around the one-year mark,” McGregor said.

The fact that the extension hasn’t deteriorated after six months could bode well for future Mars missions where astronauts could spend up to two years in microgravity during the journey.

“This preliminary finding is promising for the brain health of astronauts during long-duration missions, but it is still important to examine MRI data from a larger group of astronauts and to After long missions,” McGregor said.

Seidler added that the absence of extensions after short flights was good news for those who might consider short-haul travel, as the industry continues to grow.

Microgravity conditions also lead to other physiological effects due to the reduced physical load on the human body. These include bone and muscle atrophy, cardiovascular changes, balance system problems in the inner ear and a syndrome involving the eyes.

Another concern is the increased risk of cancer from greater exposure to solar radiation that astronauts may face as they travel further from Earth.