Bad sleep habits are associated with lower grades from high school through college

Results show that poor sleep hygiene was associated with a lower grade-point average in high school. Sleep hygiene worsened upon entering college, and poor sleep hygiene tended to persist through the senior year. Students whose sleep hygiene worsened during college also showed a greater decline in their GPA during college.

According to the American Academy of Sleep Medicine, sleep hygiene involves habits and behaviors that promote healthy sleep. Common examples include establishing a relaxing bedtime routine, and avoiding caffeine in the afternoon and at night.

"Sleep hygiene is a set of voluntary behaviors that you can change," said principal investigator and lead author Jennifer Peszka, PhD, associate professor of psychology at Hendrix College in Conway, Ark. "If they are related to college performance, then students could make small changes that help them do better. It makes sense and we can tell students they need good sleep to help them do well in college, but I think being able to point to empirical data is more convincing."

The study also found differences according to "chronotype," which reflects the time of day when a person prefers to be awake. Students who are "evening types," meaning that they have a natural preference to stay up later at night, showed greater declines in GPA transitioning from high school to college and had a lower freshman GPA (2.84) compared with morning and intermediate types combined (3.18). These night owls shifted significantly more toward a morning chronotype by the senior year of college, when there were no longer significant GPA differences between chronotypes.

"We found that these owls were shifting their clocks during their time in college to be more like morning larks and regular robins," said Peszka. "Perhaps that shift helped their academic performance improve."

Peszka, along with co-authors David Mastin, PhD, from the University of Arkansas at Little Rock and John Harsh, PhD, from the University of Southern Mississippi, studied 89 students who gave access to their high school and college academic records. During the summer before their freshman year of college, they completed a series of questionnaires about their sleep preferences, sleep habits and how they slept in high school.

Thirty-four participants completed the same questionnaires at the end of their freshman year in college, and 43 participants completed the questionnaires after their senior year. Chronotype was identified using the Horne-Ostberg criteria.

The authors concluded that students may be able to improve their academic performance by understanding their chronotype and following sleep hygiene recommendations.

Last year at SLEEP 2010, Peszka, Mastin, Harsh and colleagues reported that poor sleep hygiene was related to higher scores on a measure of perceived stress among college students. Poor sleep hygiene also was associated with higher scores on both the exhaustion and cynicism subscales of a tool that measured "burnout," a state of global exhaustion marked by excessive fatigue, reduced job efficiency and depressed mood.