Sleep is an integral part of human health and life that is crucial for learning, performance, and physical and mental health [1]. Traffic accidents, performance errors, and exacerbation of disease states have all been linked to poor sleep quality. Furthermore, individuals who must perform during their disadvantaged circadian hours (such as shift workers) are more prone to accidents and health problems [2].

There has been an increased awareness of insufficient and/or poor quality sleep among adolescents. In general, adolescents prefer to retire and rise late, in part due to a delayed melatonin release during puberty [3]. This preference is reflected by later bedtimes and longer sleep durations on holidays or weekends [4-10]. In addition, a typical adolescent requires 9 hours of sleep each night [7,9]. Ming and colleagues collected questionnaires on sleep habits, schedules, school performance and school start time from 1941 students of five high school programs in New Jersey and 585 students of a high school in Wenzhou China [9,10]. They reported a forward shift of sleep/wake cycles towards earlier rising time during weekdays; reduced sleep quantity on weekdays; and poor sleep quality, especially during weekdays. Poor sleep risk factors such as sleep initial and/or maintenance insomnia, excessive daytime sleepiness, daytime napping, alarm clock use, sleep duration less than 7 hours ranged from 36% to 80% of the participants. There was a correlation between the number of poor sleep risk factors and school performance, and between earlier start time and poor sleep quality and quantity. Furthermore, the students who compensated for shortened weekday sleep times by sleeping longer on weekends were less likely to report school performance deficits. Although the exact consequences of sleep health problems are difficult to quantify, Ming and colleagues suggested that multiple sleep health risk factors within the same subjects were more likely to result in reports of poor school performance, and weekend make-up sleep is beneficial for sleep recovery and better school performance [9,11]. Other investigators observed a similar impact of poor sleep quality, reduced total sleep time and excessive daytime sleepiness on academic performance, behavior, and social competence in adolescents [1,5,7].

Circadian rhythm has been shown to influence a wide range of physiologic and psychological functions [12-14]. Many aspects of cognition such as decision making, memory, processing speed, selective attention and vigilance are modulated by the time of day in relation to circadian rhythm [12,15-17]. In addition, studies have shown that physiologic and pathological states are affected by circadian rhythm. These include disorders of sleep such as difficulty falling asleep, shortened sleep duration, sleepiness, anxiety and irritability [9,18]. Unfortunately, most of high schools in USA start at adolescent’s disadvantaged circadian hours. High school start times contribute to sleep deprivation [19] and poor school performance among adolescents [9]. A study in Rhode Island found that a delay in school start time was associated with improvements in high school student’s alertness, mood, and health [20]. Advocacy for a delay in high school start time will likely improve students’ sleep health, thereby maximizing their potential for academic achievement.

Acknowledging the unique sleep physiology of adolescents, recognizing potential sleep health problems and learning how to avoid adverse effects of sleep deprivation are important to adolescents and their educators. Current high school curricula may not always include sleep health education. Integration of sleep education, at least sometime during the high school years, will help high school students to adjust their sleep/wake cycles.

Future study on the impact of internet use, cell phone texting and late night online chatting on sleep health is needed to address additional burden on adolescent’s sleep.