The Effect of Long Space Missions on Astronauts’ Brains Revealed

New research has shed light on the impact of space travel on the human brain, suggesting that astronauts need approximately three years to fully recover after extended missions. The study, which examined brain scans from 30 astronauts, uncovered a notable expansion of ventricles in individuals who participated in missions lasting six months or longer. The absence of gravity during space travel causes fluid shifts that lead to the enlargement of ventricles, the brain cavities filled with cerebrospinal fluid.

The findings indicate that long-duration space travel induces significant ventricular expansion, necessitating a recovery period of approximately three years. This discovery could have implications for future mission planning and the scheduling of repetitive space travel.

As we embark on a new era of space exploration, a study investigating the effects of traveling beyond Earth’s gravity suggests that frequent space travelers should allow their brains to reset physiologically by waiting three years after extended missions.

Researchers conducted a thorough analysis of brain scans taken before and after space travel involving the 30 participating astronauts. Their findings, published in Scientific Reports, demonstrate a substantial increase in the size of the brain’s ventricles in individuals who completed missions lasting at least six months. Furthermore, the study suggests that a recovery period of less than three years may be insufficient for the ventricles to fully return to their normal state.

Ventricles are responsible for housing cerebrospinal fluid, which offers protection, nourishment, and waste removal for the brain. While the human body possesses effective mechanisms for fluid distribution, the absence of gravity during space travel causes fluids to shift upwards, elevating the brain within the skull and causing ventricular expansion.

“The study revealed a correlation between the duration of space travel and the enlargement of ventricles,” said Rachael Seidler, a professor of applied physiology and kinesiology at the University of Florida and one of the study’s authors. “Given that many astronauts undertake multiple spaceflights, our research indicates that it takes approximately three years between missions for the ventricles to fully recover.”

Seidler, who is affiliated with the Norman Fixel Institute for Neurological Diseases at UF Health, highlighted that ventricular expansion is the most enduring change observed in the brain following spaceflight based on existing studies. She emphasized the need to allow the brain sufficient time to recover, as the long-term implications on the health and behavioral well-being of space travelers remain unclear.

Out of the 30 astronauts examined, eight undertook missions lasting two weeks, while 18 were involved in six-month missions, and four were in space for approximately one year. The study’s authors noted that ventricular enlargement tapered off after the six-month mark.

“The most significant changes occur when transitioning from two weeks to six months in space,” Seidler explained. “There is no measurable alteration in ventricular volume after just two weeks.”

This research brings positive news in light of the growing interest in space tourism. Shorter space trips appear to induce minimal physiological changes in the brain, Seidler added.

Although researchers have not yet been able to study astronauts who have spent more than a year in space, Seidler emphasized that it is reassuring to see that ventricular expansion levels off after approximately six months.

“We were pleased to observe that the changes do not increase exponentially, considering that we will eventually have individuals spending longer periods in space,” she noted.

The outcomes of this NASA-funded study could influence future decisions regarding crew travel and mission planning, according to Seidler.

For more information on this research, refer to the article titled “The Dark Side of Multiple Spaceflights on Human Brain Structure.”

Reference: “Impacts of Spaceflight Experience on Human Brain Structure” by Heather R. McGregor, Kathleen E. Hupfeld, Ofer Pasternak, Nichole E. Beltran, Yiri E. De Dios, Jacob J. Bloomberg, Scott J. Wood, Ajitkumar P. Mulavara, Roy F. Riascos, Patricia A. Reuter-Lorenz, and Rachael D. Seidler, published on June 8, 2023, in Scientific Reports.
DOI: 10.1038/s41598-023-33331-8

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• Scientific Reports: “Impacts of Spaceflight Experience on Human Brain Structure”
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