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On August 6, 2015, the Centers for Disease Control released results of a study of school start times that attracted considerable attention in numerous media outlets. Using data from the US Department of Education, they looked at 39,700 public middle, high, and combined schools.
The average school starting time was 8:03 AM and in 42 states, the vast majority of schools started before 8:30 AM. Only 17.7 % of schools started at 8:30 AM or later. The 8:30 AM time is important because just last year the American Academy of Pediatrics (AAP) issued a policy statement recommending that middle and high school start no earlier than 8:30 AM. I wrote a blog post about that recommendation the day after it was announced on August 25, 2014.
While school start times have crept earlier and earlier over the years, and there is much resistance to change, the movement to push school start times later has attained some momentum, and the support of the AAP and CDC may help sustain and increase that momentum. In most cases, when parent advocacy groups have succeeded in getting school boards to approve earlier starts, it has taken years of continuous lobbying.
The primary body of research providing justification for later school day starts is that which shows physiological changes in adolescence making falling asleep earlier in the evening more difficult. The numbers of supporting studies continue to grow. In one recent study (Crowley et al. 2014), actigraphs were used to track sleep timing of 94 children over a 2.5 year period, and saliva samples were collected to measure melatonin, the hormone produced in the pineal gland that responds to dim light and induces sleepiness. They found that that timing of release occurred later in the evening as children entered adolescence.
Pushing back school start times will certainly give adolescents an opportunity to get more sleep, but it will not guarantee that they get sufficient sleep, and that is one of many arguments opponents of later school start times put forth. I am in favor of later start times, but I also believe that many more factors are involved and change will be very difficult. Many engrained cultural influences work against getting sufficient sleep, including media that are accessible day and night and increasing use of caffeinated beverages by adolescents.
References
http://www.cdc.gov/features/school-start-times/index.html
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6430a1.htm?s_cid=mm6430a1_w
https://www.psychologytoday.com/blog/child-sleep-zzzs/201408/pediatrici…
Crowley SJ, Van Reen E, LeBourgeois MK, Acebo C, Tarokh L, et al. (2014) A Longitudinal Assessment of Sleep Timing, Circadian Phase, and Phase Angle of Entrainment across Human Adolescence. PLoS ONE 9(11): e112199. doi:10.1371/journal.pone.0112199
