Sleep duration and school performance in Korean adolescents

Background This study investigated the relationship between sleep duration and school performance in Korean adolescents. Methods In 2012, 63 688 adolescents participated in the 8th Korea Youth Risk Behavior Web-Based Survey (KYRBWS-VIII) project. The relationship between sleep duration and school performance was evaluated by multivariate logistic regression analysis after adjustment for covariate variables, including body mass index, age, parental education, economic status, mental stress, smoking, alcohol consumption, breakfast patterns, and three measures of physical activity. Results For boys, but not for girls, 5-6 hours of sleep/night were related to average or better academic performance (OR: 1.094, 95% Cl [1.011-1.182], p=0.025) compared to hours/night. For both boys and girls, nine or more hours/night were negatively related to academic performance (boys: 0.657, [0.554-0.779; p<0.001]; girls: hours/night, 0.664 [0.572-0.771], p<0.001) compared to hours/night. Conclusion Whilst it may appear that five to six hours of sleep are necessary to maintain average or better than average school performance for boys, nine or more hours are detrimental to school performance for both groups. This study was limited by the following factors: data were collected only for weekdays and it is. Other sleep variables, such as quality of sleep and sleepiness; should be investigated for a further understanding of these results.