Most college students are used to hearing that if they get a good night’s sleep before test day, they’ll score higher.
But a new MIT study finds that it’s not that simple.
According to the study, students need quality, consistent sleep throughout a semester to reach their academic peak. Whether they sleep well or not the night before a test doesn’t really matter.
“We’ve heard the phrase ‘Get a good night’s sleep, you’ve got a big day tomorrow.’ It turns out this does not correlate at all with test performance. Instead, it’s the sleep you get during the days when learning is happening that matter most,” Jeffrey Grossman, a professor of computational computer science at MIT and co-author of the study, said in a statement.
The study
Surprisingly, this study wasn’t originally meant to be on sleep at all. Instead, Grossman was trying to find a link between exercise and better academic performance of students in his solid-state chemistry class. So, he asked 100 of his students to wear Fitbits (88 actually did) and enrolled 22 of them in an intense fitness class for a semester.
But after the semester ended, Grossman and his co-authors surprisingly found no significant difference in the academic performance of those who took the fitness class and those who didn’t.
However, they did discover another trend.
Fitbits can also detect periods of sleep and changes in sleep quality. And when the researchers graphed the amount of sleep students received along with their semester grades, they noticed that, overall, the students who slept longer, had better quality sleep, and had a more regular sleep schedule over the course of the semester received the best grades.
“Of course, we knew already that more sleep would be beneficial to classroom performance, from a number of previous studies that relied on subjective measures like self-report surveys,” Grossman said in a statement. “But in this study the benefits of sleep are correlated to performance in the context of a real-life college course, and driven by large amounts of objective data collection.”
Sleep “really, really matters,” he added.
When you go to sleep also matters
College students have perpetually late bedtimes. With all of the late-night study sessions, enticing parties and midnight dorm room chats, college students often don’t find themselves going to sleep until around 1 a.m.
But luckily, as long as students regularly go to bed before 2 a.m., there won’t be a significant effect on their grades, the researchers found. However, 2 a.m. is the cutoff point. If students go to bed later than that, they can expect to see a dropoff in academic performance, no matter how many hours of sleep they get.
“When you go to bed matters,” Grossman said in a statement. “If you get a certain amount of sleep — let’s say seven hours — no matter when you get that sleep, as long as it’s before certain times, say you go to bed at 10, or at 12, or at 1, your performance is the same. But if you go to bed after 2, your performance starts to go down even if you get the same seven hours. So, quantity isn’t everything.”
Sleep has a surprisingly large effect on grades
Overall, the researchers found that sleep habits accounted for 25 percent of the variations in students’ grades, which is huge.
This percentage was impressive enough to catch the attention of Robert Stickhold, a professor of psychiatry and director of the Center for Sleep and Cognition at Harvard Medical School, who was not connected with this study.
“The results of this study are very gratifying to me as a sleep researcher, but are terrifying to me as a parent,” he said in a statement.
“[A] full quarter of the variation in grades was explained by these sleep parameters (including bedtime). All students need to not only be aware of these results, but to understand their implication for success in college. I can’t help but believe the same is true for high school students.”
