Adolescent sleep is typically poor in duration and quality. Sleep duration and quality reduce to suboptimal levels, and sleep duration variability and latency increases during adolescence. Sleep recommendations suggest that adolescents should obtain 8–10 hours of sleep per night. Additionally, there is a shift in the body's circadian rhythm such that sleep and wake timings become later during adolescence. Technology, social factors, and physical development are thought to contribute to poor sleep during this time. Poor sleep duration and quality in adolescents has been linked with altered brain functioning and development, poor mental and physical health, as well as higher rates of disease and mortality. The concerns surrounding poor sleep during adolescence has garnered significant public attention, especially concerning policies related to school start times.
Developmental changes
Adolescent sleep worsens with age. Specifically, longitudinal research demonstrates that sleep duration shortens during the transition from high school to college. Additionally, sleep efficiency (the amount of time spent asleep when in bed) decreased during this transition. Day-to-day variability in sleep duration increased during this transition, suggesting that adolescent sleep duration becomes less stable with time. A variety of social, physical, biological, and psychological factors change during adolescence which contributes to declines in sleep. In particular, puberty has been explored as a contributor to changes in adolescent sleep. Luteinizing hormone (LH) is secreted during sleep at the onset of pubertal maturation, pointing to an important relationship between sleep and pubertal development.
Sleep recommendations
The National Sleep Foundation recommends that teenagers (14–17 years) obtain 8 to 10 hours of sleep. Their recommendation further stipulates that less than 7 hours and more than 11 hours of sleep may be harmful. Additionally, it is recommended that young adults (18–25 years) obtain 7 to 9 hours of sleep and avoid sleep less than 6 hours and more than 11 hours.
Adolescent sleep researchers have conducted studies to provide stronger empirical evidence for sleep recommendations. Fuligni and colleagues (2019) examined a sample of American adolescents and found that younger adolescents, especially those with elevated levels of internalizing symptoms, need more sleep in order to experience optimum levels of positive mood the next day. Additionally, another study examining Mexican-American youth found that roughly 7.5 hours of sleep was predictive of high GPA but 8.75 hours of sleep was predictive of lower internalizing symptoms. This finding suggests that optimal sleep duration differs depending on the outcome.
More research is needed to understand individual differences in sleep duration during adolescence.
Sleep duration
Sleep duration has been declining since the early 90s according to research. Evidence also suggests that teen females, ethnic minorities, and those of low socioeconomic status experience the lowest durations. Puberty is thought to contribute to poor sleep during adolescence as teens undergo physical and social maturation. A burgeoning area of adolescent sleep research is focused on understanding the contribution of technology-use to poor teen sleep. Importantly, research shows that declines in adolescent sleep duration are characteristic of adolescents around the world.
Brain
Poor sleep duration has been found to be related to altered brain development during adolescence. Telzer and colleagues (2015) found that teens with greater day-to-day variability in their sleep duration had lower white matter integrity one year later. This result remained when controlling for sleep duration, which suggests that sleep variability may be more consequential for teen brain development than simply duration. Another study found that sleep duration was strongly associated with gray matter volume of the bilateral hippocampus among a sample of healthy children and adolescents.
Risk-taking
Poor sleep duration and increased risk-taking has been a well-established association in the adolescent sleep literature. A recent meta-analysis reported that poor sleep duration results in a 1.43 times greater odds of engaging in risky behaviors. The direction of the relationship between risk-taking and sleep duration is still unknown, thus causal claims cannot be made.