OHS risks are not limited to Planet Earth, with new studies showing the physical effects of working in space.

Belgian researchers have studied the brains of 11 male cosmonauts who were spending months at a time on the International Space Station, taking MRI scans before their trip, soon after they came back, and seven months after their terrestrial return.

They used this approach to evaluate the brains of cosmonauts from Roscosmos, Russia’s space program, before and about 9 days after long-duration space missions on the International Space Station, averaging 171 days.

They found proportionate increases in the quantity of gray matter tissue in the superior part of the brain, and decreases in gray matter in other parts.

They say these were changes in the distribution of tissue caused by shifts in cerebrospinal fluid, not reductions in the net quantity of gray matter.

The shifts in cerebrospinal fluid the researchers observed support previous observations that microgravity causes the brain to shift upward inside the skull, and, additionally, suggest the cerebellum shifts upward, too.

They also found that larger decreases in the sharpness of cosmonauts’ vision after spaceflight – a symptom caused by a condition called spaceflight-associated neuro-ocular syndrome (SANS) – are associated with larger expansions in the brain’s ventricles.

Luckily, most changes the researchers observed shortly after the cosmonauts returned to Earth were reversed when their brains were examined again within 7 months, although recovery in the superior portion of the brain was more pronounced than in the inferior portion.

The researchers say there is still a severe lack of detailed information on what happens to the human body in space, so many more studies are needed.

Their latest paper is accessible here.