Doctors have discovered that frequent flying can actually shrink the brain. Researchers from Bristol University, UK used MRI scans to find structural differences in the brains of cabin crew who had either 5 or 14 days to recover between flights. The scans showed that the temporal lobe region was smaller in the crew with less recovery time. These participants also performed more poorly in memory and spatial learning tasks.

It is not clear whether these changes in the brain structure are permanent but researchers believe they make a compelling statement in favor of longer intervals between flights