Sleep Regulation, Physiology and Development, Sleep Duration and Patterns, and Sleep Hygiene in Infants, Toddlers, and Preschool-Age Children

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Sleep problems are common, reported by a quarter of parents with children under the age of 5 years, and have been associated with poor behavior, worse school performance, and obesity, in addition to negative secondary effects on maternal and family well-being. Yet, it has been shown that pediatricians do not adequately address sleep in routine well-child visits, and underdiagnose sleep issues. Pediatricians receive little formal training in medical school or in residency regarding sleep medicine. An understanding of the physiology of sleep is critical to a pediatrician׳s ability to effectively and confidently counsel patients about sleep. The biological rhythm of sleep and waking is regulated through both circadian and homeostatic processes. Sleep also has an internal rhythmic organization, or sleep architecture, which includes sleep cycles of REM and NREM sleep. Arousal and sleep (REM and NREM) are active and complex neurophysiologic processes, involving both neural pathway activation and suppression. These physiologic processes change over the life course, especially in the first 5 years. Adequate sleep is often difficult to achieve, yet is considered very important to optimal daily function and behavior in children; thus, understanding optimal sleep duration and patterns is critical for pediatricians. There is little experimental evidence that guides sleep recommendations, rather normative data and expert recommendations. Effective counseling on child sleep must account for the child and parent factors (child temperament, parent–child interaction, and parental affect) and the environmental factors (cultural, geographic, and home environment, especially media exposure) that influence sleep. To promote health and to prevent and manage sleep problems, the American Academy of Pediatrics (AAP) recommends that parents start promoting good sleep hygiene, with a sleep-promoting environment and a bedtime routine in infancy, and throughout childhood. Thus, counseling families on sleep requires an understanding of sleep regulation, physiology, developmental patterns, optimal sleep duration recommendations, and the many factors that influence sleep and sleep hygiene.

Introduction

Sleep is not just the absence of waking, but an active neurophysiological process and the primary activity of the developing brain. Sleep is necessary for survival, but the major function of sleep remains elusive. Sleep duration, quality, and architecture changes over the lifespan, particularly in the first 5 years of life. Newborns spend as much as 80% of their day sleeping, and most toddlers and preschoolers spend half or more of their day asleep. Sleep has been shown to be as important to animal survival as food. Animal studies show that rat life spans are decreased from 2 to 3 years to only 5 weeks if deprived of REM sleep, and to 2–3 weeks if deprived of all sleep. Human studies demonstrate that adequate sleep in children is essential to normal growth and development, maternal and family well-being, and child sleep is associated with significant predictors of adult health. In this review, we discuss sleep regulation, biological rhythms, and sleep architecture; the neurophysiology of sleep; the development of sleep patterns in infants and young children; sleep duration and patterns: normative data, recommendations and influential factors; sleep problems; and recommended sleep hygiene.1, 2, 3, 4

Section snippets

Sleep Regulation, Biological Rhythms, and Sleep Architecture

Sleep is regulated by two overlapping but distinct systems—the circadian system and sleep/wake homeostasis.5, 6 The circadian system endogenously synchronizes biologic rhythms, including sleep, cyclically with the 24-h day and is adjusted through the influence of exogenous factors. Sleep/wake homeostasis describes the body׳s internal neurophysiologic drive toward either sleep or waking. Homeostasis is governed by the principles of equilibrium; the body is driven toward a balance between sleep

Neurophysiology of Sleep

Arousal and sleep (both NREM and REM) are dynamic physiologic processes regulated through a complex, and only partially understood, network of activation and suppression of neurologic pathways from the brainstem through the cerebral cortex (Table 1).7 A basic understanding of the neuroanatomy and neurophysiology is important for understanding the development of sleep.

Development of Sleep Patterns in Infants and Young Children

Over the first year of life, infant sleep patterns change. Newborns usually sleep most of the day and night, waking only for feeding every 1–3 h, whereas a typical 1-year-old sleeps 10–12 h at night without waking, followed by two daily naps.1

Over the first few months, the ability to retain calories increases and caloric need and growth relative to size decreases. This allows infants to consume adequate calories during the day and require progressively fewer nighttime meals to sustain growth.

Sleep Duration and Patterns: Normative Data, Recommendations, and Influential Factors

In the first 5 years of life, many parents and children struggle with sleep and sleep-related behaviors. Adequate sleep duration is a topic that is frequently discussed among parents and pediatricians, and pediatric sleep research has clearly shown that insufficient sleep has negative impacts on neurobehavioral and cognitive functions, health and well-being.1, 20, 21, 22 Due to methodological difficulties, experimental evidence detailing best and most appropriate sleep durations in children is

Sleep Problems

Sleep problems are common and often behavioral in origin, due to factors such as child temperament and development, parenting style or affect, child–parent interactions, and environmental factors. There are also parasomnias, which are episodic, undesirable behaviors that occur with sleep.11 Nightmares occur during REM sleep, typically early in the morning, most commonly in primary school-age children, though do occur in 1.9–3.9% of preschool-age children.11 Management includes avoidance of

Recommended Sleep Hygiene

Healthy sleep patterns can be established and sleep problems can be prevented and managed through sleep-promoting parenting practices, or good “sleep hygiene.” Good quality sleep, particularly nighttime sleep, encourages full daytime alertness.51, 70

Routines are critical to good sleep hygiene, specifically consistent sleep schedules and pre-sleep routines. Routines benefit young children by providing them with a sense of predictability and security, and help with activity transitions. They also

Conclusion

There are many aspects of sleep that have significant effects on child and family health and well-being. Pediatricians report little formal training in sleep medicine, yet patients frequently report infant and child sleep problems. Basic physiology and development of sleep patterns, normative sleep durations, and the many influencing factors are important to understanding and diagnosing child sleep problems. Pediatricians should discuss sleep hygiene and early adoption of healthy sleep habits

References (76)

  • J.A. Mindell et al.

    Cross-cultural differences in infant and toddler sleep

    Sleep Med

    (2010)
  • M. Hirshkowitz et al.

    National Sleep Foundation׳s sleep time duration recommendations: methodology and results summary

    Sleep Health

    (2015)
  • M. Hirshkowitz et al.

    National Sleep Foundation׳s updated sleep duration recommendations: final report

    Sleep Health

    (2015)
  • M.D. Nevarez et al.

    Associations of early life risk factors with infant sleep duration

    Acad Pediatr

    (2010)
  • C.J. Bottino et al.

    The association of urbanicity with infant sleep duration

    Health Place

    (2012)
  • T.G. O′Connor et al.

    Prenatal mood disturbance predicts sleep problems in infancy and toddlerhood

    Early Hum Dev

    (2007)
  • W.A. Goldberg et al.

    Eye of the beholder? Maternal mental health and the quality of infant sleep

    Soc Sci Med

    (2013)
  • K.A.T. Pinheiro et al.

    Chronicity and severity of maternal postpartum depression and infant sleep disorders: a population-based cohort study in southern Brazil

    Infant Behav Dev

    (2011)
  • T. Kubota et al.

    Effects of nocturnal bright light on saliva melatonin, core body temperature and sleep propensity rhythms in human subjects

    Neurosci Res

    (2002)
  • T. Roehrs et al.

    Caffeine: sleep and daytime sleepiness

    Sleep Med Rev

    (2008)
  • J.A. Mindell et al.

    Developmental aspects of sleep hygiene: findings from the 2004 National Sleep Foundation Sleep in America Poll

    Sleep Med

    (2009)
  • J.A. Owens

    The practice of pediatric sleep medicine: results of a community survey

    Pediatrics

    (2001)
  • L.J. Meltzer et al.

    Prevalence of diagnosed sleep disorders in pediatric primary care practices

    Pediatrics

    (2010)
  • A.A. Borb et al.

    Sleep homeostasis and models of sleep regulation

    J Biol Rhythms

    (1999)
  • R.A. España et al.

    Sleep neurobiology from a clinical perspective

    Sleep

    (2011)
  • S. Daan et al.

    Timing of human sleep: recovery process gated by a circadian pacemaker

    Am J Physiol

    (1984)
  • J.A. Mindell et al.

    A Clinical Guide to Pediatric Sleep: Diagnosis and Management of Sleep Problems

    (2009)
  • C.B. Saper et al.

    Hypothalamic regulation of sleep and circadian rhythms

    Nature

    (2005)
  • S. Sheldon et al.

    Anatomy of sleep

    Pediatric Sleep Medicine

    (1992)
  • R. Ferber

    Solve Your Child׳s Sleep Problems

    (2006)
  • S.A. Rivkees

    Developing circadian rhythmicity in infants

    Pediatrics

    (2003)
  • H.P. Roffwarg et al.

    Ontogenetic development of the human sleep-dream cycle

    Science

    (1966)
  • L.M. O′Brien et al.

    Sleep disturbances in children with attention deficit hyperactivity disorder

    Pediatr Res

    (2003)
  • J.A. Williams et al.

    Norms and trends of sleep time among us children and adolescents

    JAMA Pediatr

    (2013)
  • J.F. Hagan et al.

    Bright Futures: Guidelines for Health Supervision of Infants, Children, and Adolescents

    (2008)
  • C.N. Jacklin et al.

    Sleep pattern development from 6 through 33 months

    J Pediatr Psychol

    (1980)
  • S. Paruthi et al.

    Recommended amount of sleep for pediatric populations: a consensus statement of the American Academy of Sleep Medicine

    J Clin Sleep Med

    (2016)
  • S. Paruthi et al.

    Recommended amount of sleep for pediatric populations: a statement of the American Academy of Sleep Medicine

    J Clin Sleep Med

    (2016)
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    This research was supported in part by Grant UL1 TR000038 from the National Center for Advancing Translational Sciences, National Institutes of Health.

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