In 1997, the National Institutes of Health issued a “Working Group Report on Problem Sleepiness.” While recognizing that “problem sleepiness and its consequences affect all segments of society to some extent” it singled out two groups for its report – shift workers and adolescents – because “there is evidence that the prevalence of problem sleepiness is high and increasing in these groups, with particularly serious consequences.” [i]
A few years later, the American Academy of Pediatrics followed suit, establishing its own working group in conjunction with other organizations. Its report, published in the June 2005 issue of Pediatrics, stated that “adolescents and young adults are often excessively sleepy. This excessive sleepiness can have a profound impact on school performance, cognitive function, and mood and has been associated with other serious consequences such as increased incidence of automobile crashes.” [ii]
Adolescents need nine to ten hours of sleep per night -- the same as younger children. However, surveys conducted nationwide and here in New Canaan reveal that the majority of high school students sleep less than seven hours on school nights.
This is a cause for concern on many levels. If a person receives insufficient sleep, it does not mean simply that he or she will feel more tired the next day. Sleep is not a time when we just “shut down.” The body and brain are extremely busy during the night, and cutting sleep short compromises the physiological and neurological activities necessary to ensure optimal physical, emotional and mental functioning.
Both the quantity and quality of nightly sleep are important. A person cycles through two different types of sleep each night in predictable patterns. When a person wakes up earlier than the body demands, this architecture is disrupted and the person misses a significant amount of REM sleep, the stage where dreams occur and which is associated with the consolidation of learning and memory.
The body keeps track of missing sleep time. With each night of insufficient sleep, students add to a growing “sleep debt” which must be repaid. While the effects of sleep debt can be masked through temporary arousal, the underlying burden remains. Caffeine consumption, daytime napping and extended weekend sleep are all signs that adolescents are sleep deprived; these efforts to self-stimulate or catch up on sleep, while perhaps understandable and even necessary, compound the problem by making it more difficult to fall asleep at night.
Sleep debt is cumulative. By missing at least two hours of sleep each night, by Friday, these students are walking around with an accumulated ten to fifteen hours of sleep debt – the equivalent of at least a full night’s sleep.
A shift to later sleep patterns is one of the most notable developmental changes as children proceed into puberty. Hormonal changes alter circadian rhythms in adolescents. The alerting cues of the biological clock, which occur in peaks and troughs throughout the day to maintain wakefulness in the face of growing pressure from the biological sleep drive, create a situation where adolescents feel quite awake at night, even when they are severely sleep deprived. Melatonin, the hormone that induces drowsiness, is released at a later hour during adolescence. With early start times for school, adolescents are being woken up in the wrong phase of the circadian cycle, as melatonin levels are still elevated and body temperature is at its minimum, indicating a body still in sleep mode.
The world of the adolescent changes, too, which exacerbates the biological propensity for later bedtimes. A growing autonomy, greater academic responsibilities and increased opportunity for social and extracurricular activities contribute to changes in sleep patterns. The availability of electronic diversions also has an impact on sleep habits. As intrinsic biological changes and external influences intertwine, it is difficult for adolescents to fall asleep at an hour which is compatible with early wakeup times.
The resulting nightly sleep deprivation has profound consequences. From the standpoint of mental and emotional functioning, sleep deprivation cuts to the very core of what it means to be an adolescent. Developing social competence, learning to integrate emotions with thinking and planning, is the work of adolescence and sleep deprivation takes a profound toll on these capabilities. The prefrontal cortex (the part of the brain responsible for impulse control, planning and reasoning) matures during adolescence by establishing the architecture of neural pathways for the adult brain; adequate sleep is essential to this process.
Insufficient sleep has a documented impact on a variety of cognitive, emotional and physical functions. Whether it is an adolescent’s ability to handle stress, combat depression, maintain alertness, consolidate new knowledge, ward off infection, drive safely or resist the allure of illicit substances, sleep is essential to daily functioning.
Experts have identified early school start times as biologically inappropriate for adolescents and a contributing factor to limited sleep time. The experience of schools that have moved to a later opening high school bell has shown that students receive more sleep: morning sleep is extended, while bedtimes remain virtually the same.
The evidence that adolescents are sleep deprived and that this has a profound impact on their well-being and development is clear and compelling. Deciding what to do about it is the more difficult challenge with the logistical issues that would accompany any start time changes, should the Board of Education decide to take on this action.
Yet, as revealed in the surveys administered by the League in 2006 to the public school community, there clearly is strong dissatisfaction with the current 7:30 start time for 7th – 12th graders from parents with students in those grades, as well as expressed anxiety from parents anticipating the future for their younger children. There is general satisfaction with the elementary school start times, although this satisfaction is greater at South School, which starts at 8:20 a.m., than it is for East and West, which start later. Faculty views on start time changes are mixed and show trends according to school, age group taught and length of employment.
A strong majority of parents with students at the 7:30 start time felt that moving to a later time would be acceptable in terms of starting sports and extracurricular activities later.
On June 1, 2006 the League of Women Voters of New Canaan issued a position statement that adolescent sleep deprivation is a serious public health issue that must be addressed. The League recommended that information about sleep be incorporated into educational programs in New Canaan public schools and that the school system investigate all options to implement a later starting time for 7th – 12th graders.
The pioneering sleep researcher, Dr. William C. Dement, says that out of all the knowledge he has accumulated in his fifty years of sleep research, “none is more important than the topic of sleep debt.” [iii] Any advance in the start time would be beneficial to begin reducing the burden of sleep debt for our adolescents.
A look at start times would address one piece of the puzzle, but so too may it be worthwhile for the members of our community to consider the cultural factors which help push bedtimes for many adolescents to alarmingly late hours.
As children enter adolescence, the challenges they face intensify enormously, with the increasing academic obligations and the responsibilities and pressures that accompany a growing autonomy. As a community, we must do all we can to support the ability of our adolescents to navigate these critical years safely and successfully and establish the healthy habits that will ensure their well-being throughout their lives.
[i] Dinges, D., M. Carskadon, R. Dahl, V. Haulcy, T. Monk, T. Roehrs, J.Walsh and T. Wehr. Working Group Report on Problem Sleepiness. National Center on Sleep Disorders Research and Office of Prevention, Education and Control, National Institutes of Health; National Heart, Lung, and Blood Institute; August 1997; p. 1.
[ii] Millman, R. “Excessive Sleepiness in Adolescents and Young Adults: Causes, Consequences and Treatment Strategies.” Pediatrics. American Academy of Pediatrics, Technical Report, 2005; p. 1.
[iii] Dement, W. and C. Vaughn. The Promise of Sleep. New York: Dell Publishing; 1999; p. 51.