This warping of time apparently does not result from the brain speeding up from adrenaline when in danger. Instead, this feeling seems to be an illusion, scientists now find.
Instead, such time warping seems to be a trick played by one's memory. When a person is scared, a brain area called the amygdala becomes more active, laying down an extra set of memories that go along with those normally taken care of by other parts of the brain.
Eagleman added this illusion "is related to the phenomenon that time seems to speed up as you grow older. When you're a child, you lay down rich memories for all your experiences; when you're older, you've seen it all before and lay down fewer memories. Therefore, when a child looks back at the end of a summer, it seems to have lasted forever; adults think it zoomed by."