Quit smoking. Turn off the computer. Go to bed.

It could improve your grades. Of course, parents have always known that. Now, in the first study of its kind, researchers at the University of Minnesota have proved it.

They matched grade-point averages with the typical health problems such as smoking, drinking and stress reported by nearly 10,000 Minnesota college students. They found a clear connection between student health and academic success.

“Health is important,” even for young adults who seem to be in the prime of their lives, says Dr. Ed Ehlinger, director of Boynton Health Services at the University of Minnesota and a lead author of the study. Both parents and college administrators “need to make sure that students have access to health care.”

What affects grades the most? Stress, excessive screen time, binge drinking and gambling. Students who reported eight or more emotional stresses – anything from failing a class to a conflict with parents – had an average GPA of 2.72. Those who said they had no significant stress reported an average GPA of 3.3.

The ability to handle stress was equally important, the survey found. Those who said they could effectively manage it performed much better than those who said they couldn’t. That’s an important finding, because it can persuade colleges to provide students with the resources they need to learn how to manage stress, Ehlinger says.

Earlier surveys showed that students who spend a lot of time on the computer, watching TV or playing video games were more likely to engage in other unhealthful habits such as eating fast food, Ehlinger says. Now it’s clear that these activities cut into their grades as well. Four or more hours of screen time a day resulted in an average GPA of 3.04 or less. Less than an hour a day bumped it up to 3.3 or better.

The same pattern held with binge drinking. Teetotalers reported an average GPA of 3.31, compared with 2.99 for students who drank excessively at least once in the previous two weeks.