Astronauts' brains show signs of damage after long missions, study finds

Shorter recovery periods between spaceflights may not allow for complete brain structure recovery

A new study highlights the potential impact of extended spaceflights on astronauts' brain structure. Getty

Astronauts experience significant changes in brain structure after long missions, a new study has found.

The study underscores the need for ample recovery time between flights, researchers said.

Experiencing space flight, particularly in terms of extended missions and shorter recovery periods in between, induces fluid changes in astronauts' brains that may not return to normal before subsequent flights, according to a recent study published in Scientific Reports.

The researchers, led by Prof Rachael Seidler and colleagues, discovered that space travel leads to considerable changes in human brain structure, particularly in the expansion of the ventricles.

These are cavities within the brain filled with cerebrospinal fluid, which progressively enlarge with extended space missions lasting up to six months, the study found.

It remains uncertain whether these changes vary with different mission lengths or the number of prior space flights.

In the study, Dr Seidler's team used MRI to scan the brains of 30 astronauts both before and after space flights.

The astronauts had undergone a range of missions, from two-week stays in space (eight astronauts), six-month missions (18 astronauts), to even longer missions (four astronauts).

The researchers found that longer space flight missions resulted in greater ventricular enlargement, which gradually tapered off after six months in space.

“People who spend just a couple of weeks show little to no change in these structures,” Dr Seidler's told The National.

“This is good news for those going on short space junkets. Ventricular volume increases for those that travelled for six months or close to a year.”

If the gap between missions was less than three years, astronauts' ventricles did not increase at all.

The researchers noted that seven astronauts who had a shorter recovery period between missions showed little to no enlargement of the ventricles post-flight compared to preflight.

This led the researchers to propose that a three-year gap between space flights might not be enough recovery time.

“This suggests that the folks who had travelled within the past three years did not have sufficient time for recovery of their ventricles,” Dr Seidler added.

The study sheds light on how prior and current space flight experiences might influence brain changes, an understanding that becomes increasingly vital as space flights become more frequent and prolonged.

The findings could aid in devising better guidelines for future mission planning.

Nevertheless, the authors pointed out that the exact impact of ventricular expansion on space travellers is not currently understood, and more long-term health follow-ups are required.

“This ventricular expansion could (likely) compresses the surrounding brain tissue,” Dr Seidler's told The National.

“Ventricular enlargement can be associated with cognitive decline.”

The research also highlights the concept of “compensatory capacity” of the ventricles and its relation to the recovery time between space flights.

The researchers suggested that a three-year gap might be necessary between missions for recovery.

However, more research is needed, and the potential health and performance effects of these changes have yet to be determined.

As for potential countermeasures or interventions that could mitigate the impact of space flight on the brain, the research mentioned several methods under investigation, such as exercise, nutrition, artificial gravity, and lower body negative pressure.

Nasa is funding several studies to further explore the effects of space flight on the brain and potential mitigation strategies, emphasising the importance of long-term recovery tracking after space missions.