Students who sleep seven hours per night during the exam period score an average of 1.7 points higher (on a scale of 20) on their exams than peers who get only six hours of sleep. Researchers at Ghent University and KU Leuven surveyed 621 first-year students about the quality of their sleep during the exam period and correlated it with their exam performance.
In total, approximately 30 percent of students received a score of 5 on the Pittsburg Sleep Quality Index (PSQI) – good for the label of ‘bad sleeper’. More female students (35 percent) than male students (26 percent) fell in the ‘bad sleeper’ category. The researchers corrected their results to account for differences in socio-economic background and general health traits.
“All else equal, students who generally got a good night’s sleep performed better on exams,” says Dr. Stijn Baert (Ghent University). “Students who fell one standard deviation (and thus significantly) above the average PSQI score achieved almost a full point less for each exam they sat.”