University of Minnesota
October 20, 2008
Up too late? Inadequate sleep is linked to lower grades in college, a new study finds.
Photo: Rodrigo Zamith
Good health may hold the key to good grades, a new study indicates
By Deane Morrison
It may seem obvious that college students ought to go easy on staying up late, drinking, and various other behaviors, but no one could demonstrate a clear link between such habits and lower academic performance. Until now, that is. A new study of Minnesota college students indicates that when behaviors and situations affect student health, grades also tend to head south.
A survey of 9,931 undergraduates from 14 Minnesota colleges and universities found that factors like smoking, drinking, lack of sleep or exercise, and financial difficulties correlated with lower grade point averages (GPAs). The study included all five University of Minnesota campuses.
"Our study shows that there is a direct link between college students' health and their academic achievement," says Ed Ehlinger, director of the U's Boynton Health Service, which conducted the survey. "This is the first time that anything like this has been published, where grade point average is linked to all these behaviors."
The report, "Health and Academic Performance: Minnesota Undergraduate Students," is available online.
Often, the differences in GPA between two groups of students were less than a tenth of a point. But, says Ehlinger, when applied to a sample of more than 9,000 students, the impact is huge.
Physical exercise was associated with stronger minds as well as muscles. Students reporting low, moderate, or high levels of physical activity in the previous week had an average GPA of 3.24. The self-reported nonexercisers posted a significantly lower 3.18 GPA.
A particularly striking graph in the report shows the steady slide of GPAs as students spend more time watching TV or using a computer for games or other recreation. The average GPA for those who reported watching no TV on an average day was 3.25, compared to 3.04 for students who spent more than five hours in front of the tube. Computer games and other recreational computer use also affected performance; those who refrained averaged a 3.32 GPA versus 2.98 for the five-plus hours crowd.
Watch a video featuring a student who thinks he really ought to get more sleep.
"Turning off the computer or TV and going to sleep is one of the best things our students can do to improve their grades," Ehlinger observes.
Both smoking and using smokeless tobacco were associated with lower GPAs. For example, those who smoked even infrequently averaged a 3.12 GPA, compared to 3.28 for students who reported not smoking.
"Even students who smoked once or twice in a month had lower GPAs than those who didn't smoke," Ehlinger says. The good news: a solid 75 percent of students reported not smoking at all in the previous month.
Drinking showed a similar correlation. Seventy percent of students reported using alcohol during the previous month. Abstainers posted an average GPA of 3.29, while those who drank on at least 20 of 30 days managed a significantly lower 3.10. High-risk drinking (more than five drinks in one sitting) was also associated with a drop in GPA; 39 percent of students reported that behavior at least once in the past month.
In the realm of sleep, half of the students (50.3 percent) reported getting adequate sleep on only three or fewer days during the previous week. Those students' mean GPA was 3.22--significantly lower than the 3.26 for students reporting adequate sleep on four or more days. Similarly, those reporting enough sleep on four or five nights had a significantly lower GPA (3.25) than those reporting six or seven nights (3.29).
"The more days students get adequate sleep, the better GPAs they attain," Ehlinger says. "There is a direct link between the two."
The study also examined the effects of several other factors, including sexual assault, mental health, and illegal drug use.
Ehlinger expressed hope that the report will encourage students to take care of themselves.
"This is a great report for parents, students, faculty, and health care providers," he says. "It gives all these folks something to work with in helping students succeed in their academic careers."