Dutch College Study Finds that 'Evening Types' Have Poorer Focus, Lower Grades

A new Dutch survey found that college students with a chronic lack of sleep experience great difficulty concentrating on their schoolwork and in turn have lower grades. Many of these students are “evening types,” those who gain more energy later in the day and into the night. 

The study involved nearly 1,400 healthy students at Dutch universities and is based on a national survey by the Netherlands Association for Sleep Wake Research, Leiden University and the Netherlands Brain Foundation.

Young people require eight to nine hours of sleep in order to function properly, according to research at the National Sleep Foundation. Of the students surveyed, more than one-third reported not feeling rested enough to study properly. In fact, students who suffer from a chronic lack of sleep scored significantly lower on their final exam in the current academic year and had a significantly lower average grade than those who got enough sleep.

Of the respondents, 32 percent say they are evening types and seven percent say they are morning types (61 percent say they are neither). The evening types have more energy in the evenings than the other types and tend to go to bed later. Therefore, evening types have shorter sleeping times (eight hours and six minutes) than the average (eight hours and 20 minutes) and the morning types (eight hours and 28 minutes).

The evening types find it harder to keep their eyes open if they are sitting for a prolonged period of time in a lecture or working group and are less interested in studying because they feel too sleepy.

“’As the evening types sleep for less time every day than the average and morning types, they build up a sleep deficit over time. Evening types are more likely to have to get up in the morning while their biological clock hasn’t yet given them a signal to wake up. This can have a negative effect on the rest of the day,” says lead researcher Dr. Kristiaan van der Heijden from Leiden University.

“Regular bedtimes are extra important for these people and sleeping through to the afternoon in order to make up for lost sleep is disastrous for their sleep rhythm.”

Nearly all students agree that drinking coffee or other caffeine-containing drinks after dinner can cause sleeping problems. But there some negative habits and behaviors that many students believe are positive.

For example, 52 percent of students believe that participating in an intensive sport just before going to bed can have a positive influence on their sleep, while in fact this is not the case, as exercise raises body temperature and keeps one feeling wired and energetic. Drinking alcohol is another common misconception, as 30 percent of students believe that it affects sleep positively, while research has shown that the opposite is the case.

Source: Universiteit Leiden