Age-related changes in sleep/wake patterns among Korean Teenagers

• Published in: Pediatrics (Evanston) 2005, Vol.115 (1), p.250-256
• Main Authors: YANG, Chang-Kook, KIM, Jung K, RAJNIKANT PATEL, Sanjay, LEE, Jeong-Hyeong
• Format: Article
• Language: English
• Subjects: Adolescent; Aging - physiology; Asian people; Biological and medical sciences; Care and treatment; Child; Child development; Child psychology; Childhood sleep disorders; Circadian Rhythm; Culture; Diagnosis; Female; General aspects; Health aspects; Health Surveys; Humans; Korea; Male; Medical sciences; Pediatrics; Prevalence; Sleep - physiology; Sleep deprivation; Sleep Deprivation - ethnology; Sleep disorders in children; Teenagers; Youth
• ISSN: 0031-4005; 1098-4275
• DOI: 10.1542/peds.2004-0815g

As children go through the transition from childhood to adolescence, many shifts occur in sleep/wake patterns related to intrinsic and extrinsic developmental changes. These shifts have been shown to result in corresponding shifts in sleep phase (later sleep onset) and sleep deprivation among teenagers in Western societies. However, the effect of these developmental changes on the sleep habits of Korean teenagers has not been analyzed. This study aims to quantify age-related changes in sleep/wake patterns among Korean teenagers and elucidate cultural and other factors causing these changes. The School Sleep Habits Survey was administered in homeroom classes to students in grades 5 to 12 (mean age: 13.7 +/- 2.4 years) selected via a 2-way stratification sampling method. The survey included items regarding usual sleep/wake patterns over the previous 2 weeks as well as measures of daytime sleepiness, sleep/wake-problem behavior, depressed mood, and morningness/eveningness. A total of 1457 students (52.9% male) completed the survey. The higher the grade, the later bedtime was found to be on both school days and weekends. There was a similar relationship between increasing grade and earlier wake time on school days, but higher grades were associated with later wake time on weekends. Total sleep time decreased by approximately 3 hours on school nights and 1 hour on weekend nights from grades 5 to 12. Adolescents were severely sleep deprived, with mean school-night total sleep times of 6.02, 5.62, and 4.86 hours for 10th-, 11th-, and 12th-graders, respectively. In the higher grades, there was a greater discrepancy between school nights and weekends in terms of bedtime and wake time, and the magnitude of weekend oversleep increased. Older students also reported more daytime sleepiness, more sleep/wake-problem behavior, more depressed mood, and more eveningness preference. The chief reasons students cited for their sleep deprivation differed across grades: Academic demands and entertainment (such as Internet and television) were reported by 5th- and 6th-graders, entertainment and then academic demands by 7th-, 8th-, and 9th-graders, and early school start time and academic demands by 10th-, 11th- and 12th-graders. This study clearly demonstrates that Korean adolescents do not get adequate sleep and that they have profound discrepancies in their sleep/wake patterns between school and weekend nights. Compared with previous studies from other countries, Korean student