We've all been there: procrastination has led to an all-night study session before that big exam.
According to a new study, our efforts won't matter - we're doomed.
Scientists from the University of California, Los Angeles (UCLA) found that students who lacked sleep had more academic problems than those who got rest the night before, said ABC News.
"Sacrificing sleep for extra study time is counterproductive," said Andrew J. Fuligni, a professor of psychiatry and biobehavioral sciences at UCLA, in a statement.
"Academic success may depend on finding strategies to avoid having to give up sleep to study, such as maintaining a consistent study schedule across days, using school time as efficiently as possible, and sacrificing time spent on other, less essential activities."
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The study looked at 535 students over a number of their high school years, measuring both sleep and academic performance.
Researchers found that as students got older, their academic performance was more likely to be hindered by a lack of sleep.
As the teens aged, they reported that cramming had negatively affected their test scores and ability to concentrate in class, said the Daily News.
Yet, critics say that the experiment may be fatally flawed in that poor performers may, in fact, be the ones cramming.
"It is equally possible that the extra study is the result of the student knowing they have a problem with material that shows up on the test," David Rapoport, associate professor of medicine and director of the sleep medicine program at NYU School of Medicine told ABC News.
The findings were published in the journal Child Development.