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Early school days and late-night screen time exacerbate American teens’ sleep deprivation

Original Article By: Horacio de la Iglesia

Summarized By: Neurobit

Every school year, parents and caregivers of preteens and teenagers are faced with the challenge of getting their children out of bed in the morning. This is often attributed to laziness in teens, but the main reason why healthy individuals are unable to wake up naturally without an alarm is that they are not getting the sleep their brain and body need.

Studies have shown that adolescents require more than nine hours of daily sleep to be physically and mentally healthy. However, it is unlikely that many teenagers are getting enough sleep. In the United States, less than 30% of high school students, or those in grades 9 through 12, sleep the recommended amount, according to the Centers for Disease Control and Prevention. Among middle schoolers in grades 6 through 8, nearly 60% do not get enough sleep at night.

Research conducted by Horacio de la Iglesia, a professor of biology and sleep expert at the University of Washington who has been studying sleep and circadian rhythms for more than 30 years, suggests that a much higher percentage of teens are getting too little sleep. Their research found that, just as in other areas of the U.S., high schoolers in Seattle are not getting the amount of sleep they need. Factors contributing to this lack of sleep include a physiological regulation of sleep that leads to delayed sleep timing in teens, lack of morning exposure to daylight, and excessive exposure to bright electric light and screens late in the evening.

It is commonly understood that teenagers often have a preference for going to bed later and waking up later than adults. This tendency can be attributed to a combination of factors related to the brain's regulation of sleep. Adolescents have a physiological regulation of sleep that leads to a delayed sleep timing, which is not aligned with early school start times. Additionally, a lack of morning exposure to daylight and excessive exposure to bright electric light and screens late in the evening also contribute to this delayed sleep timing.

In order to address this issue, some school districts have chosen to delay the start time for middle schools and high schools. The American Academy of Pediatrics recommends that schools for this age group should not start before 8:30 a.m. However, the majority of high schools in the U.S start at 8 a.m. or earlier.

Research has shown that delaying school start times can have a positive impact on students' sleep. A study conducted by the University of Washington found that students gained 34 minutes of daily sleep after the Seattle school district delayed middle school and high school start times by nearly an hour. Additionally, student attendance and punctuality improved, and median grades went up by 4.5%.

It is important for teens to learn healthy habits that promote sufficient sleep such as getting exposure to bright daylight in the morning and avoiding exposure to light emitted by screens in the evening. Sufficient sleep can improve physical and mental health, enhance overall performance, and mitigate the risk of students developing depression and anxiety, obesity, and addictive behavior.


Early school days, late-night screen time exacerbate American teens' sleep deprivation. (2023, January 16). CW39 Houston. Retrieved January 18, 2023, from

Iglesia, H. d. l. (2022, September 16). School start times and screen time late in the evening exacerbate sleep deprivation in US teenagers. The Conversation. Retrieved January 18, 2023, from

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