https://www.youtube.com/watch?v=R57ocxW3faA
When children become teenagers, hormonal changes shift their circadian rhythm—they get tired later. Since schools typically don't adapt to their new natural

https://sproutsschools.com/why-teens-are-tired-in-school/
The Circadian Rhythms: Why Teens Are Tired in School. When children become teenagers, hormonal changes shift their circadian rhythm—they get tired later. Since schools typically don't adapt to their new natural sleep cycle, they often get less sleep during weekdays, affecting their memory retention, emotional well-being, and health.

https://www.youtube.com/watch?v=rRzNd19ZaNk
Circadian Rhythms: Why Teens Are Tired in School.When children become teenagers, hormonal changes shift their circadian rhythm-they get tired later. Since sc

https://my.clevelandclinic.org/health/articles/circadian-rhythm
That's why circadian rhythms closely relate to day and night. Circadian rhythm in babies, toddlers and children. ... But your teen may not get tired until much later now. Their melatonin level may not rise until around 10:00 p.m. or 11:00 p.m. And as they're going to bed later, they need to sleep later into the morning.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4824552/
One of the early changes associated with puberty is alteration of a child's circadian rhythms, such that adolescents are more alert in the afternoons and evenings and require morning sleep. 44 Their natural body clocks can keep adolescents awake until 11 PM or later, in spite of going to bed earlier and good sleep hygiene, such as avoiding

https://www.sleepfoundation.org/teens-and-sleep
School-age: 6-12 years: 9-12 hours: Teen: 13-18 years: 8-10 hours: Adult: 18 years and older: ... Experts believe this is a two-fold biological impulse affecting the circadian rhythm and sleep-wake cycle of teens. First, teens have a sleep drive that builds more slowly, which means they do not start to feel tired until later in the evening

https://www.uclahealth.org/medical-services/sleep-disorders/patient-resources/patient-education/sleep-and-teens
There is a shift in the timing of your circadian rhythms. Before puberty, your body makes you sleepy around 8:00 or 9:00 pm. When puberty begins, this rhythm shifts a couple hours later. Now, your body tells you to go to sleep around 10:00 or 11:00 pm. The natural shift in a teen's circadian rhythms is called "sleep phase delay."

https://www.teacherspayteachers.com/Product/Circadian-Rhythms-Why-Teens-Are-Tired-in-School-11582273
When children become teenagers, hormonal changes shift their circadian rhythm—they get tired later. Since schools typically don't adapt to their new natural sleep cycle, they often get less sleep during weekdays, affecting their memory retention, emotional well-being, and health. If we want teenagers to learn and prosper, schools could do

https://neurosciencenews.com/circadian-rhythm-teen-sleep-neurobiology-1508/
November 7, 2014. By following dozens of younger and older adolescents for more than two years, researchers in a new study were able to determine that the children fell asleep later and their circadian rhythms shifted later as they grew older. But early school start times interfere with their tendency to sleep later, reducing their total sleep.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6060007/
Circadian misalignment, or a discrepancy between sleep behaviors and the endogenous circadian rhythm, is common among adolescents. The majority of research has indicated that a discrepancy between sleep timing on school days compared to weekends (i.e., "social jetlag") is related to worse grades, lower overall cognitive ability, and lower

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4844764/
Introduction. Research conducted over the past four decades has demonstrated that acquiring adequate sleep and maintaining a sleep schedule that is consistent with physiological circadian rhythmicity is a component of normal growth and development during childhood and adolescence.[] Adequate sleep is needed to achieve optimal mental and physical alertness, daytime functioning, and learning

https://www.healthline.com/health/healthy-sleep/circadian-rhythm
Teenagers experience a shift in their circadian rhythm known as sleep phase delay. Unlike in their childhood years with early bedtimes around 8 or 9 p.m., teenagers may not get tired until much

https://www.nature.com/articles/s41598-022-06209-4
Early school times fundamentally clash with the late sleep of teenagers. This mismatch results in chronic sleep deprivation posing acute and long-term health risks and impairing students' learning.

https://www.hopkinsmedicine.org/health/wellness-and-prevention/teenagers-and-sleep-how-much-sleep-is-enough
"Teens experience a natural shift in circadian rhythm," says Johns Hopkins sleep expert Laura Sterni, M.D. This makes it more difficult for them to fall asleep before 11 p.m. Add in early school start times and an increase in homework, extracurricular activities and sometimes a part-time job, and sleep deprivation in teens becomes common.

https://www.neurologylive.com/view/teenage-circadian-rhythm
In the teenage years, the hormonal response to the 24-hour daily light/dark exposure that influences circadian rhythm is altered, making adolescents physiologically yearn to stay awake later at night and to remain asleep later in the day. The role of melatonin in sleep. Melatonin is the naturally occurring hormone that is cyclically released in

https://www.sciencedaily.com/releases/2018/04/180425195621.htm
Ji has studied the circadian rhythm of sleep (a person's 24-hour cycle). A developmental change takes place in circadian rhythm during adolescence; teenagers' rhythm shifts one to two hours later

https://www.bbc.com/worklife/article/20191023-the-body-clock-science-behind-later-school-start-times
A new law passed early this month will push start times later for most schools; high schools will start no earlier than 08:30 and middle schools 08:00. The move is aimed at improving teenagers

https://theconversation.com/the-biological-reason-why-its-so-hard-for-teenagers-to-wake-up-early-for-school-88802
The social starting times for school and university - typically between 7.30am and 8.30am - are too early for teenagers the world over. The biological changes that teenagers go through mean

https://www.tandfonline.com/doi/pdf/10.1080/17439884.2014.942666
During adolescence biological changes dictate both a sleep duration of nine hours and later wake and sleep times, a phenomenon found in other mammals (Hagenauer et al. 2009; Rüger et al. 2012). At its peak the combination of these two biological changes leads to a loss of two to three hours sleep every school day.

https://link.springer.com/chapter/10.1007/978-3-030-43803-6_7
Contributing factors include the hormonal changes occurring during puberty that are associated with changes in their circadian rhythms, parental involvement in setting teens' bedtimes and awakenings, curfews, school schedules, part-time employment, and teens' use of alcohol, caffeine, and other drugs [14, 15]. For example, parents of even

https://link.springer.com/content/pdf/10.1007/978-3-030-43803-6_7.pdf
Circadian Rhythms A growing body of literature about circadian rhythms began to support the profound effects of various rhythmic patterns in living organisms. Weinert et al. [2] contended that circadian rhythms develop in early childhood, although at different rates and times. There was mounting evidence that circadian rhythms were generated endog-

https://scienceandliteracy.org/reasons-why-school-should-start-later/
7. Reduced Stress. The stress induced by early mornings and lack of sleep can significantly affect students' academic and social lives. By moving the start of the school day later, schools can alleviate a major source of daily stress, contributing to a healthier, more conducive learning environment.

https://www.futurity.org/sleep-teenagers-parents-3170592/
Teens' circadian rhythms make high school start times a legitimate obstacle to getting healthy sleep, says Kole. Grover recommends an ideal start time of 9 AM, while Kole emphasizes that most