The typical adolescent schedule of “late to bed and late to rise,” in combination with highly structured school schedules requiring an early start time, often leads to reduced sleep duration among students. Compounding the issue is the fact that students are required to be in class all morning, yet most school classrooms do not provide adequate light to stimulate the circadian system in the morning, especially in dark winter months. As adolescents spend more time indoors, they miss out on essential morning light needed to reset the circadian system daily and promote entrainment to the 24-hour solar day.1 In late spring, if adolescents spend more time outdoors after school, the circadian clock may be delayed by evening daylight exposure.2 Sleep can be further compromised by melatonin-reducing evening light from backlit electronic devices such as laptops and tablets.3, 4
Some evidence has emerged suggesting that the sensitivity to light by the circadian system is greater in adolescents than in adults.3, 5 LRC research has shown that adolescents (age 15-17 years) are more sensitive to evening light from self-luminous devices than those in their twenties.3 Crowley, Carskadon, and colleagues recently showed that younger adolescents are more sensitive to evening light than older adolescents, with significantly greater melatonin suppression from exposure to light during the evening.5 Evening light exposures may be particularly disruptive of sleep in younger adolescents.5
A lighting intervention designed to deliver light starting mid-morning (after 9 a.m.) until the end of the school day and provisions to reduce evening light exposures, such as the use of orange-tinted glasses and the control of exposure to self-luminous devices, may help shift the timing of sleep in adolescents. Successful light therapy in this population will likely involve both school administrators and family members.
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 Given that light after core body temperature nadir will advance the timing of the biological clock, and therefore sleep times, and that adolescents may have a later core body temperature nadir than middle-aged people, light exposure should be timed so that it falls after core body temperature nadir. Therefore, we are proposing to start delivering the light starting mid-morning.
LRC Light & Adolescents Website: http://www.lrc.rpi.edu/programs/lightHealth/LightAdolescents.asp
Leslie R et al. Patterns to Daylight Schools for People and Sustainability. U.S. Green Building Council, 2010. http://www.lrc.rpi.edu/programs/daylighting/pdf/DaylightingPatternBook_Final.pdf
Figueiro MG. Delayed sleep phase disorder: clinical perspective with a focus on light therapy. Nature and Science of Sleep, 2016. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4830627
Figueiro MG and Rea MS. Evening Daylight May Cause Adolescents to Sleep Less in Spring than in Winter. Chronobiology International, 2010. http://www.ncbi.nlm.nih.gov/pubmed/20653452
Figueiro MG and Rea MS. Lack of short-wavelength light during the school day delays dim light melatonin onset (DLMO) in middle school students. NeuroEndocrinology Letters, 2010. http://www.ncbi.nlm.nih.gov/pubmed/20150866
Wood B et al. Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression. Applied Ergonomics, 2013. http://www.ncbi.nlm.nih.gov/pubmed/22850476
Figueiro MG and Overington D. Self-luminous devices and melatonin suppression in adolescents. Lighting Research & Technology, 2015. http://lrt.sagepub.com/content/early/2015/05/06/1477153515584979.abstract
Bridges A. Screen time can mess with the body's 'clock.' Science News for Students, 2015. https://student.societyforscience.org/article/screen-time-can-mess-body%E2%80%99s-%E2%80%98clock%E2%80%99
Cardwell D. High-Tech Lights to Help Baby Sleep, or Students Stay Alert. The New York Times, 2015. http://www.nytimes.com/2015/09/12/business/energy-environment/high-tech-lights-to-help-baby-sleep-or-students-stay-alert.html
Pearson C. Teens Need More Morning Light, Study Shows. Voice of America, 2010. https://youtu.be/JYYOOobe5ls