The old aphorism that “you snooze, you lose” doesn’t apply to students who stay up late to cram for a test or finish a class project. New research shows that sacrificing sleep for school work is a bad trade.

Researchers from UCLA‘s Jane and Terry Semel Institute for Neuroscience and Human Behavior enlisted students from three Los Angeles high schools to help them figure out whether academic performance suffered the day after a late night of studying.

It turned out their hunch was correct: Lost sleep resulted in less comprehension during class and worse performance on tests, according to their report, published online Tuesday in the journal Child Development.

“Sacrificing sleep for studying seems to be counterproductive,” said Andrew J. Fuligni, a developmental psychologist at UCLA and the study’s senior author.

READ MORE: Click below