Parents who admire their kids’ late-night study habits might be better off encouraging them to get some shut-eye instead — new research suggests well-rested students fare better academically.

After UCLA researchers tracked 500 high school students to see how sleep affected their grades, they found that the older the kids got, the more impact sleep deprivation had.

By the time they were seniors, students who sacrificed sleep for studying reported diminished test performance or having trouble understanding class material.

“Although studying is essential, sleep is important for learning,” says Dr. Phyllis C. Zee, professor of neurology and director of the Sleep Disorders Center at Northwestern University. “Even one night of sleep loss can negatively affect performance.”

Experts say the solution is not to study less (sorry, kids) but to space it out more so that an all-night cram session isn’t required.

[ABC News]