There is a common belief that children are not getting enough sleep and that children’s total sleep time has been declining. Over the century, many authors have proposed sleep recommendations. The aim of this study was to describe historical trends in recommended and actual sleep durations for children and adolescents, and to explore the rationale of sleep recommendations.
A systematic literature review was conducted to identify recommendations for children’s sleep requirements and data reporting children’s actual total sleep time. For each recommendation identified, children’s actual sleep time was determined by identifying studies reporting the sleep duration of children of the same age, gender, and country in the same years. Historical trends in age-adjusted recommended sleep times and trends in children’s actual sleep time were calculated. A thematic analysis was conducted to determine the rationale and evidence-base for recommendations.
Thirty-two sets of recommendations were located dating from 1897 to 2009. On average, age-specific recommended sleep decreased at the rate of –0.71 minute per year. This rate of decline was almost identical to the decline in the actual sleep duration of children (–0.73 minute per year). Recommended sleep was consistently ∼37 minutes greater than actual sleep, although both declined over time.
A lack of empirical evidence for sleep recommendations was universally acknowledged. Inadequate sleep was seen as a consequence of “modern life,” associated with technologies of the time. No matter how much sleep children are getting, it has always been assumed that they need more.
Comments
Analogies to Children's Sleep
30 April 2012
Matricciani and colleagues, conclude: "Inadequate sleep was seen as a consequence of 'modern life,' associated with technologies of the time. No matter how much sleep children are getting, it has always been assumed that they need more."
Matricciani, et al, draw an analogy between sleep and eating: "sleeping longer does not indicate a need for more sleep, in the same way that eating more does not indicate a need for more food." This analogy has some limitations. For example, I can double my daily food consumption for an extended period (let's say 6 months) but I cannot double the amount of time I spend asleep for such an extended period. I might lie in bed twice as long but, over an extended period, I will not succeed in sleeping twice as long.
I think there is another analogy to food and diet worth considering.
Children with ADHD have more sleep problems (1, 2, 3) and poor sleep quality itself can lead to ADHD-like symptoms of inattention and hyperactivity (4, 5).
Among children, the poor sleep associated with ADHD-like symptoms is analogous to an unhealthy lifestyle and diet. In particular, inattention and hyperactivity are analogous to obesity and poor physical fitness. A reduction in ADHD-like symptoms and improvement in academic performance are analogous to a reduction in BMI and improved physical fitness. Improved sleep is analogous to improved diet and exercise.
Experts recommend parameters for optimal sleep (sleep hygiene) and experts recommend parameters for optimal diet and exercise (healthy lifestyle).
Matricciani and team note that the issue of children's sleep "has drawn from the same well of discourse for more than a century" and suggest that this is due to a lack empirical support. However, it might be simply due to the persistence of children's sleep as a public health issue. Again, this is analogous to poor physical fitness and obesity. All of these problems are more prevalent than ever before. It would appear that despite the technological advances of "modern" society, the diet and lifestyle of our children is worse than it was, let's say, a century ago. You might say there has "never been a good enough diet or lifestyle" for children but it is also true that the consequences of a poor diet and lack of exercise among our children have never been more problematic or prevalent. Likewise, it may be said that there for children there is "never enough sleep" but it is probably also true that "not enough sleep" for our children has never been more concerning or prevalent.
References
1. Hvolby A, et al. Parental rating of sleep in children with attention deficit/hyperactivity disorder. Eur Child Adolesc Psychiatry 2009; 18: 429-438.
2. Li S, et al. Sleep problems in Chinese school-aged children with a parent-reported history of ADHD. J Atten Disord 2009; 13: 18-26.
3. Owens J, et al. Subjective and objective measures of sleep in children with attention-deficit/hyperactivity disorder. Sleep Med 2009; 10: 446-456.
4. Gruber R, et al. Impact of sleep restriction on neurobehavioral functioning of children with attention deficit hyperactivity disorder. Sleep 2011; 34(3): 315-323.
5. Paavonen EJ, et al. Short sleep duration and behavioral symptoms of attention-deficit/hyperactivity disorder in healthy 7- to 8-year old children. Pediatrics 2009; 123: e857-e864.
Conflict of Interest:
None declared
AAP Executive Committee Response
The Academy acknowledges the vital importance of sleep to children-s health and well-being, supports the scientific legitimacy of healthy sleep recommendations for children and adolescents, and stands firmly behind pediatric sleep medicine experts in issuing these recommendations. Moreover, the Academy is developing a Policy Statement on school start times for middle and high school students which is based on sound scientific evidence.
Conflict of Interest:
None declared
Sleep Recommendations
One of the papers cited by Matricciani et al. (2012), was by Lewis Terman and Adele Hocking in the Journal of Educational Psychology, 1913. Matricciani et al. say "In 1913, Lewis Terman expressed a common opinion that '...physicians and writers on school hygiene agree that children are less likely to receive less sleep than is needful to them.'" (p.138). Here's a quote that was not used by Matricciani et al. that characterizes the conclusion of Terman and Hocking about sleep needs: "As regards the school child, the wisest course in all probability is for us to make the conditions such that the child will spontaneously sleep as many hours a day as he wants to sleep, while avoiding all conditions which would tend to abbreviate or unduly prolong the sleep beyond the standard. Liberal allowance should also be made for individual differences, for not all the range of variation which we have found in the hours of sleep for children at any particular age can be accounted for on the basis of habit and environment. There are undoubtedly physiological idiosyncrasies which make nine hours for one child equivalent to eleven hours for another." (p.208). Matriacciani et al. cite recommendations of sleep need for most of the 15 sources (e.g. Dukes, 1899) included in the Terman and Hocking paper, but they fail to mention the above, which is what Terman and Hocking actually recommend. Matriacciani et al. were looking for definitive guidelines and since Terman & Hocking gave none, they failed to report the wise and nuanced view they do give. That view, consistent with the Owens et al. letter, and I expect consistent with the views of Matriacciani et al. was reasonable in 1913 and remains so 99 years later.
Conflict of Interest:
None declared
Response to 'A letter to the editor in defence of sleep recommendations'
We were interested to read the comments of Dr Owens and her colleagues on our paper (1). There has been considerable interest in this paper from the academic, research and wider media community, many of which have incorrectly interpreted their inferences as our implications. To clarify, our paper did not state that:
* there is no need for sleep recommendations;
* current recommendations for sleep are wrong; or
* children do not require more sleep than they are currently getting.
Our paper did not claim that no evidence exists to support current sleep guidelines.
We agree with Dr Owens and colleagues that sleep is important for the health and well-being of children. As our paper acknowledges, there have been numerous studies to suggest that short sleep duration is associated with a wide range of negative health outcomes. We also agree that there is indicative evidence that children are not getting enough sleep. Our paper, however, had quite a different focus. The study, largely historical in scope, reported that very little evidence has been evinced to justify sleep guidelines. This is quite different from the claim that the evidence does not exist; we say merely that it has not been marshalled or used to justify sleep guidelines when they have been presented. One is a claim about the provision of evidence, the other is a claim about the facts of the matter.
But let us turn to the substantive issue of whether current sleep guidelines are justified. The response of Dr Owens and her colleagues to our paper suggests that evidence that short sleep is associated with undesirable outcomes is in itself a justification for sleep guidelines as they are currently offered. Whether children are not getting enough sleep, and what the optimal amount of sleep is, are related but logically distinct issues. We disagree with Dr Owens and her colleagues that there is high-level, low risk of bias evidence for current sleep guidelines. While Dr Owens and colleagues claim that there is strong evidence to support current sleep guidelines, it is difficult to reconcile the evidence base underpinning the radically different guidelines in the past, which recommended much longer sleep durations. The belief that "we've got it right now" in spite of being "not so right" for the last 115 years, should in itself give us pause for thought.
There are several ways in which we could gain insight into children's sleep needs. The simplest is to see how much children are sleeping at the moment, observe that they are sleepy or report wanting to sleep more, and add on "a bit". This method seems to have been widely used, as our study shows. But the logic here is askew. It would be akin to seeing how much children eat, observing that they often say they are hungry, and deciding that they need to eat "a bit more". Normative sleep reports cannot be used to inform sleep recommendations since "just because the majority is doing something (or not doing something, in the case of sleep) doesn't make it healthy" (2). In this respect, it is interesting to note that there are very substantial differences in the amount of sleep children get across the world (3). Adolescents from Asian countries sleep 40-60 minutes less each night than American children, and 60-120 minutes less than European and Australian children. Given these large differences, the concept of a "biological sleep need" unfiltered by socio-cultural context is very problematical.
A second method is to use "unconstrained sleeping", that is, letting children sleep for as long as they feel necessary. The celebrated and unique Carskadon study (4, 5) examined unconstrained sleeping in a very small sample (n=19) of American children aged ten years and over in the 1970s. On the National Sleep Foundation website (6) this study is the only evidence cited to support the "knowledge" that adolescents "need 9.25 hours of sleep a night". Even with a far larger sample, range of ages and socio-cultural contexts, this approach is methodologically flawed: it would be like presenting children with a smorgasbord and concluding that the amount they eat is the amount they need (7, 8).
Finally, sleep need could be determined by sleep extension and sleep restriction studies that monitor relevant outcome variables. Such studies are quite rare, particularly in ecologically valid contexts. Dr Owens and her colleagues cite five such intervention studies (9-13). However, these studies looked at a very narrow range of outcomes (exclusively cognitive and behavioural), they had small sample sizes (median n = 16), and four of the five were conducted in North America, the other in Israel. Only one (13) used gradations of sleep restriction/extension which would allow us to make conclusions about optimal sleep.
So the corpus of evidence provided by Dr Owens and colleagues supports the idea -- which we do not contest -- that children could do with more sleep. It does not support the very specific guidelines laid down by the US National Sleep Foundation or anyone else over the last 115 years.
Dr Owens and colleagues constructively suggest specific papers (14- 17) for inclusion in our review. However, none of the papers proffered offer sleep guidelines or recommendations, and were therefore not retrieved - and not appropriate - for our systematic review. Furthermore, none of the papers suggested offers evidence for specific sleep guidelines, and one (16) acknowledges that "no formally accepted sleep guidelines exist".
Like Dr Owens and colleagues, we think sleep is an important issue and agree that children would most likely do better with more sleep. But we feel that the available sleep extension and sleep restriction studies should be augmented by further high-level, low risk of bias evidence to support the very specific guidelines for optimal sleep duration.
References
1.Matricciani LA, Olds TS, Blunden S, Rigney G, Williams MT. Never enough sleep: a brief history of sleep recommendations for children. Pediatrics. 2012;129:548-556.
2. Wilkoff W. Letter to the editor: sleep need in children. Pediatrics. 2003;112:1463-1464.
3. Olds T, Blunden S, Forchino F, Petkov J. The relationships between sex, age, geography and time in bed in adolescents: a meta-analysis of data from 23 countries. Sleep Medicine Reviews. 2010;14:371-378.
4. Carskadon M. Determinants of daytime sleepiness: adolescent development, extension and restriction of nocturnal sleep; Doctoral Dissertation; Stanford University; California, USA. 1979.
5. Carskadon MA, Harvey K, Duke P, Anders TF, Litt IF, Dement WC. Pubertal changes in daytime sleepiness. Sleep. 1980;2:453-460.
6. National Sleep Foundation. Backgrounder: later school start times. Available at: http://www.sleepfoundation.org/article/hot- topics/backgrounder-later-school-start-times. Accessed 2010 February.
7. Horne J. Sleepfaring: A journey through the science of sleep. New York, NY: Oxford University Press; 2006.
8. Harrison Y, Horne JA. Should we be taking more sleep? Sleep. 1995;18:901-907.
9. Berger RH, Miller AL, Seifer R, Cares SR, Lebourgeois MK. Acute sleep restriction effects on emotion responses in 30- to 36-month-old children. [published online ahead of print October 11, 2011]. Journal of Sleep Research. 2011. http://onlinelibrary.wiley.com/doi/10.1111/j.1365- 2869.2011.00962.x/full. Accessed February 17, 2012.
10. Gruber R, Wiebe S, Montecalvo L, Brunetti B, Amsel R, Carrier J. Impact of sleep restriction on neurobehavioral functioning of children with attention deficit hyperactivity disorder. Sleep. 2011;34:315-323.
11. Beebe DW, Rose D, Amin R. Attention, learning, and arousal of experimentally sleep-restricted adolescents in a simulated classroom. Journal of Adolescent Health. 2010;47:523-525.
12. Randazzo AC, Muehlbach MJ, Schweitzer PK, Walsh JK. Cognitive function following acute sleep restriction in children ages 10-14. Sleep. 1998;21:861-868.
13. Sadeh A, Gruber R, Raviv A. The effects of sleep restriction and extension on school-age children: what a difference an hour makes. Child Development. 2003;74:444-455.
14. Iglowstein I, Jenni OG, Molinari L, Largo RH. Sleep duration from infancy to adolescence: reference values and generational trends. Pediatrics. 2003;111:302-307.
15. Iglowstein I, Latal Hajnal B, Molinari L, Largo RH, Jenni OG. Sleep behaviour in preterm children from birth to age 10 years: a longitudinal study. Acta Paediatrica. 2006;95:1691-1693.
16. Eaton DK, McKnight-Eily LR, Lowry R, Perry GS, Presley-Cantrell L, Croft JB. Prevalence of insufficient, borderline, and optimal hours of sleep among high school students - United States, 2007. J Adolescent Health. 2010;46:399-401.
17. Galland BC, Taylor BJ, Elder DE, Herbison P. Normal sleep patterns in infants and children: A systematic review of observational studies. [published online ahead of print July 23, 2011]. Sleep Medicine Reviews 2011. http://www.sciencedirect.com/science/article/pii/S1087079211000682. Accessed February 17, 2012
Conflict of Interest:
None declared
Sleep Recommendations for Children: a Need for More Data
We wish to comment on Matricciani et al's(1) interesting historical survey of recommended and reported sleep durations and the spirited rejoinder it elicited from Owens and coauthors. We believe that both groups make important points, and we add perspective from our recent experimental findings.
Matricciani and coworkers show that, over the last century, age- specific recommended sleep durations decreased by 0.71 min/yr, almost the same as the reported sleep duration decline of 0.73 min/yr. Importantly, recommended sleep was consistently ~30 min greater than actual (estimated) sleep. Matricciani et al note that these recommendations, surely well- meaning, were not evidence-based.
The rejoinder by Owens et al cites the emotional, behavioral and cognitive impairments that can result from insufficient sleep. Their deep concern for children's welfare is evident. The negative impact of insufficient sleep is well established. Nevertheless, the fact remains that there are no rigorous empirical data that establish the amount of sleep needed at various ages across childhood-adolescence. The amounts of sleep obtained in unconstrained conditions are not sufficient. As Matricciani et al suggest, we require dose-response experiments that vary sleep schedules and measure the effects on daytime sleepiness, vigilance, cognitive function and affect. Ideally, these studies would be longitudinal to determine how this dose-response relation changes across childhood and adolescence.
Matricciani and coworkers point out that population studies of sleep are often more feasible than direct sleep measurement with polysomnography. There is strong evidence that both are essential. Sleep is not a unitary condition but consists of cyclically alternating, qualitatively different brain states (NREM and REM). Differential changes in these states across adolescence cannot be inferred from reported sleep times, but they are critical for understanding brain development and the function of sleep.
Combining population studies with parallel EEG recordings in a subset of subjects might be optimally informative. A useful example is provided by the cross-sectional population data of Olds et al(2) and our (independent) longitudinal study of sleep durations from ambulatory EEG recordings in children's homes(3). In their survey of 4032 Australian youngsters, Olds et al found that reported sleep durations on school night schedules decreased by 12 min/yr across ages 9-18 yrs. Our longitudinal study measuring school night sleep EEG across the same age range revealed a similar rate of decline (10.3 min/yr). However, the two kinds of biological sleep changed differently: the decline in school-night sleep time entirely resulted from decreasing NREM sleep. REM sleep increased slightly but significantly. (As we demonstrated in our article, this result cannot be attributed to sleep restriction.) It is of further biological interest that REM and NREM sleep also exhibited different trajectories across adolescence under the (separate) extended sleep condition of our experiment.
In summary, it seems fair to conclude that more research is needed, that some should be population and some laboratory based, and that these additional data will advance our understanding of both sleep biology and brain development. They will also provide a firmer and more rational foundation for public health recommendations.
1. Matricciani L. A., Olds T. S., Blunden S., Rigney G., Williams M. T. Never Enough Sleep: A Brief History of Sleep Recommendations for Children. Pediatrics. 2012; Epub ahead of print.
2. Olds T., Maher C., Blunden S., Matricciani L. Normative data on the sleep habits of Australian children and adolescents. Sleep. 2010;33(10):1381-1388.
3. Feinberg I., Davis N. M., de Bie E., Grimm K. J., Campbell I. G. The maturational trajectories of NREM and REM sleep durations differ across adolescence on both school-night and extended sleep. American Journal of Physiology Regulatory, Integrative and Comparative Physiology. 2012; Epub ahead of print.
Conflict of Interest:
None declared
Re:A Letter to the Editor in Defense of Sleep Recommendations
As a pediatrician advocating a change to later school start times in Okaloosa County, Florida where the first bus stop time for high schoolers is 5:40a.m., I agree with the response letter from the sleep researchers that there is an overwhelming number of research articles that provide data regarding the hours of sleep needed by infants, children and teens. Adolescents need a minimum of 8.5 hours of sleep each night to avoid the increased risks of mental and physical health problems and to increase the chances for academic success. Please go to startschoollater.net and sign on to the petition for later school start times around the nation.
Conflict of Interest:
None declared
A Letter to the Editor in Defense of Sleep Recommendations
Dear Dr. First:
As an international group of pediatric sleep specialists and healthcare professionals deeply committed to the health and welfare of children and adolescents, we the undersigned feel compelled to respond to the conclusions outlined in the article "Never Enough Sleep: A Brief History of Sleep Recommendations for Children, published in Pediatrics, Vol 129 (3), March 2012.(1) In particular, we strenuously challenge the validity of the statement that there is a "universally acknowledged" lack of "meaningful evidence" for sleep recommendations. While we acknowledge there is still much we need to learn and we fully support and encourage additional research on optimal sleep in children, there have been a significant number of rigorous pediatric sleep research studies, many of which were not included in the paper, which have done much to help address the issue of optimal sleep duration and healthy sleep practices in children and adolescents. (2-5) The publication of this article and the unfortunate subsequent sensationalistic media coverage (i.e., "100 Years of Sleep Recommendations...ALL WRONG") have not only misrepresented an entire body of scientific literature, but importantly, may ultimately lead parents to make misinformed and misguided decisions that effect their children's health and well-being.
In addition, the implication that the discrepancy found by the authors between recommended sleep amounts and hours of sleep actually obtained on average by children and adolescents is essentially due to "inflation" of sleep needs by experts is an over-simplified and misleading interpretation of the study findings. In fact, this new study's data instead suggest that both parental practices and practitioner recommendations are growing increasingly misaligned with children's actual biological needs.
What we do understand and can state unequivocably is the increasingly compelling evidence for the negative impact of an insufficient quantity and/or quality of sleep on children's physical and mental health, cognitive function, behavior and academic success,(6- 11) consequences for which children from racial/ethnic minorities and those living in poverty may be at even higher risk.(12,13) There are a large number of cross- sectional and prospective studies which have consistently shown associations between insufficient sleep and a host of adverse health outcomes in children and adolescents, including increased obesity risk,(14) higher rates of motor vehicle accidents(15) and accidental injuries,(16) cardiovascular health,(17) and depression,(18) and suicidal ideation.(19) Furthermore, a number of methodologically rigorous experimental studies have demonstrated the negative outcomes of sleep restriction and the positive impact of sleep extension on cognitive function in children and adolescents.(8, 20-23)
We recognize that there is significant variability in sleep needs from child to child, and across age ranges. As a result, there is no single "magic number" for the duration of sleep needed by children of a certain age, and recommendations are always based on a range of hours. Moreover, any guidelines on recommended number of hours of sleep are always given in the context of other clues which parents can use to determine whether their child or adolescent is receiving sufficient sleep, such as not waking spontaneously in the morning, excessive daytime sleepiness, and requiring additional sleep on weekends and during school vacations. Finally, recommendations regarding sleep amounts are not as implied by the authors "stand alone," but are, in fact, just one component of empirically-based healthy sleep practice guidelines provided to caregivers, which also include such issues as electronics in the bedroom,(24) caffeine consumption,(25) bedtime routines and regular sleep- wake schedules. (26-28)
In sum, this article has done a great disservice to children and families as healthcare consumers by suggesting that current guidelines for healthy sleep amounts are ill-founded, exaggerated and unreliable, and, as advocates for children's health, we are deeply concerned about the potentially detrimental effect on the health and well-being of children and adolescents around the globe.
Judith Owens MD MPH, Merrill Wise MD
Leyla Akanli MD
Candace Alfano PhD
Rosana Alves MD
Thomas Anders MD
Strahil Atanasov MD
Dean Beebe PhD
Julie Boergers PhD
Tyish Hall Brown PhD
Oliviero Bruni MD
Joseph A. Buckhalt PhD
Melissa Burnham PhD
Kelly C. Byars PsyD
Margaret-Ann Carno PhD, MBA, RN, CPNP
Mary Carskadon PhD
Sangeeta Chakravorty MD
Siupun Chan MD
Maida Chen MD
Barry A. Cohen MD
Nicky Cohen PhD
Penny Corkum PhD
Lilia Curzi-Dascalova MD
Michael Dubik MD
Richard Ferber MD
Dominic B. Gault MD
Peter Glusker MD PhD
Roger Godbout PhD
Mark G. Goetting MD
David Gozal MD
Michael Gradisar PhD
Ann Halbower MD
Shelby F. Harris PsyD
Allison Harvey PhD
Jacki Henderson PhD
Timothy Hoban MD
Lewis Kass MD
Sharon Keenan PhD
Irena Keller PhD
Declan Kennedy PhD
Amit Khanna MD
Michael H. Kohrman MS, MD
Suresh Kotagal MD
Sanjeev Kothare MD
Jyoti Krishna MD
Monique Lebourgeois PhD
John F. Leonard MD
Albin Leong MD
Robin Lloyd MD
Matthew C. Lundien MD
Kurt Lushington PhD
Cami Matthews, MD
Lisa Meltzer PhD
Jodi Mindell PhD
Gary Montgomery MD
William Moorcroft PhD
Melisa Moore PhD
Sydney Nau PhD
Rafael Pelayo MD
Rosa Peraita-Adrados MD, PhD
Judi Profant PhD
Mary Rose PsyD
Carol Rosen MD
Mark Rosenblum PsyD, LP
Saul A. Rothenberg PhD
Nancy Rothstein BA
Anat Scher PhD
Lynelle M. Schneeberg PsyD
John N. Schuen MD
Yakov Sivan MD
Kingman Strohl MD
Shannon Sullivan MD
Nadav Traeger MD
Mary H. Wagner MD
Teresa Ward PhD
Wendy L. Ward PhD
Shelley Weiss MD
Amy Wolfson PhD
Catherine Wubbel MD
1. Matricciani LA, Olds TS, Blunden S, Rigney G, Williams MT. Never Enough Sleep: A Brief History of Sleep Recommendations for Children. Pediatrics. 2012;129:548-556.
2. Iglowstein I, Jenni OG, Molinari L, Largo RH. Sleep duration from infancy to adolescence: reference values and generational trends. Pediatrics. 2003;111:302-7.
3. Iglowstein I, Latal Hajnal B, Molinari L, Largo RH, Jenni OG. Sleep behaviour in preterm children from birth to age 10 years: a longitudinal study. Acta Paediatr. 2006;95:1691-3.
4. Eaton DK, McKnight-Eily LR, Lowry R, Perry GS, Presley-Cantrell L, Croft JB. Prevalence of insufficient, borderline, and optimal hours of sleep among high school students - United States, 2007. J Adolesc Health. 2010;46:399-401.
5. Galland BC, Taylor BJ, Elder DE, Herbison P. Normal sleep patterns in infants and children: A systematic review of observational studies. [published online ahead of print July 23, 2011]. Sleep Med Rev 2011. http://www.sciencedirect.com/science/article/pii/S1087079211000682. Accessed February 17, 2012
6. Wolfson AR, Carskadon MA. Understanding adolescents' sleep patterns and school performance: a critical appraisal. Sleep Med Rev. 2003;7:491-506.
7. Beebe DW. Cognitive, behavioral, and functional consequences of inadequate sleep in children and adolescents. Pediatr Clin North Am. 2011;58:649-65.
8. Berger RH, Miller AL, Seifer R, Cares SR, Lebourgeois MK. Acute sleep restriction effects on emotion responses in 30- to 36-month-old children. [published online ahead of print October 11, 2011]. J Sleep Res. 2011. http://onlinelibrary.wiley.com/doi/10.1111/j.1365- 2869.2011.00962.x/full. Accessed February 17, 2012
9. Arman AR, Ay P, Fis NP, Ersu R, Topuzoglu A, Isik U, et al. Association of sleep duration with socio-economic status and behavioural problems among schoolchildren. Acta Paediatr. 2011;100:420-4.
10. Gruber R, Laviolette R, Deluca P, Monson E, Cornish K, Carrier J. Short sleep duration is associated with poor performance on IQ measures in healthy school-age children. Sleep Med. 2010;11:289-94.
11. Feinberg I, Campbell IG. Sleep EEG changes during adolescence: an index of a fundamental brain reorganization. Brain Cogn. 2010;72:56-65.
12. Nevarez MD, Rifas-Shiman SL, Kleinman KP, Gillman MW, Taveras EM. Associations of early life risk factors with infant sleep duration. Acad Pediatr. 2010;10:187-93.
13. Spilsbury JC, Storfer-Isser A, Drotar D, Rosen CL, Kirchner LH, Benham H, et al. Sleep behavior in an urban US sample of school-aged children. Arch Pediatr Adolesc Med. 2004;158:988-94.
14. Magee L, Hale L. Longitudinal associations between sleep duration and subsequent weight gain: A systematic review. [published online ahead of print July 23, 2011]. Sleep Med Rev. 2011. http://www.sciencedirect.com/science/article/pii/S1087079211000608. Accessed February 17, 2012.
15. Vorona RD, Szklo-Coxe M, Wu A, Dubik M, Zhao Y, Ware JC. Dissimilar teen crash rates in two neighboring southeastern Virginia cities with different high school start times. J Clin Sleep Med. 2011;7:145-51.
16. Boto LR, Crispim JN, de Melo IS, Juvandes C, Rodrigues T, Azeredo P, et al. Sleep deprivation and accidental fall risk in children. Sleep Med. 2012;13:88-95.
17. Gangwisch JE, Malaspina D, Babiss LA, Opler MG, Posner K, Shen S, et al. Short sleep duration as a risk factor for hypercholesterolemia: analyses of the National Longitudinal Study of Adolescent Health. Sleep. 2010;33:956-61.
18. Lin JD, Tung HJ, Hsieh YH, Lin FG. Interactive effects of delayed bedtime and family-associated factors on depression in elementary school children. Res Dev Disabil. 2011;32:2036-44.
19. Fitzgerald CT, Messias E, Buysse DJ. Teen sleep and suicidality: results from the youth risk behavior surveys of 2007 and 2009. J Clin Sleep Med. 2011;7:351-6.
20. Gruber R, Wiebe S, Montecalvo L, Brunetti B, Amsel R, Carrier J. Impact of sleep restriction on neurobehavioral functioning of children with attention deficit hyperactivity disorder. Sleep. 2011;34:315-23.
21. Beebe DW, Rose D, Amin R. Attention, learning, and arousal of experimentally sleep-restricted adolescents in a simulated classroom. J Adolesc Health. 2010;47:523-5
22. Randazzo AC, Muehlbach MJ, Schweitzer PK, Walsh JK. Cognitive function following acute sleep restriction in children ages 10-14. Sleep. 1998;21:861-8.
23. Sadeh A, Gruber R, Raviv A. The effects of sleep restriction and extension on school-age children: what a difference an hour makes. Child Dev. 2003;74:444-55. 24. Van den Bulck J. The effects of media on sleep. Adolesc Med State Art Rev. 2010;21:418-29, vii.
25. Bryant Ludden A, Wolfson AR. Understanding adolescent caffeine use: connecting use patterns with expectancies, reasons, and sleep. Health Educ Behav. 2010;37:330-42.
26. Hale L, Berger LM, LeBourgeois MK, Brooks-Gunn J. A longitudinal study of preschoolers' language-based bedtime routines, sleep duration, and well-being. J Fam Psychol. 2011;25:423-33.
27. Mindell JA, Telofski LS, Wiegand B, Kurtz ES. A nightly bedtime routine: impact on sleep in young children and maternal mood. Sleep. 2009;32:599-606.
28. Mindell JA, Meltzer LJ, Carskadon MA, Chervin RD. Developmental aspects of sleep hygiene: findings from the 2004 National Sleep Foundation Sleep in America Poll. Sleep Med. 2009;10:771-9.
Conflict of Interest:
None declared