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  • Andrea Nizic

The Importance of Sleep

It is known that sleep has important implications for brain functioning, health, and overall well-being. Despite understanding how crucial sleep is to healthy functioning, people often do not get enough sleep, ultimately impacting their day-to-day lives. It is typically recommended that school-aged children receive between 10 to 13 hours of sleep, an amount that decreases to between 8 to 10 for teenagers (Hirshkowitz et al., 2015). Adults should aim to get around 7 to 9 hours of sleep whereas those above 65 should aim slightly lower with 7 to 8 hours (Hirshkowitz et al., 2015). Although individuals may experience trouble with sleep occasionally, consistent occurrences such as insufficient duration, interrupted sleep, or extreme daytime sleepiness can lead to further issues with mood, attention, and behaviour.

Stages of sleep

Depending on what source one refers to, there are between 4 to 5 recognized stages of sleep, 4 of non-rapid eye movement (NREM) and 1 of REM sleep. The first NREM stage is when an individual is drowsy, with reduced body movements and responsiveness. Stage 2 sleep is considered the onset of true sleep, when eye movements and muscle tone decrease and breathing and heart rate start to slow down (El Shakankiry, 2011). Stages 3 and 4 are similar deep sleep stages when the body is relaxed, and there is slow breathing and a decreased heart rate (El Shakankiry, 2011). The last stage is REM sleep, which is when an individual can be observed moving their eyes rapidly. This is when dreams, nightmares, muscle twitches, vocalizations, muscle paralysis, and changes in heart and breathing rate occur (El Shakankiry, 2011).

What processes are affected by sleep loss?

Attention is especially sensitive to the amount of sleep that one receives and performance on attentional tasks and goal-directed behaviours worsen as the amount of sleep decreases (Krause et al., 2017). Individuals who have insufficient sleep may experience erratic shifts of attention and may lose and regain attention often (Krause et al., 2017). Another area affected by sleep disruption is reward processing and behaviours such as risk-taking. It is often that individuals who are experiencing sleep deprivation may have inaccurate representations of reward and punishment, ultimately struggling when it comes to decision-making. These individuals will be more impulsive and will make more risky decisions, with a greater chance of punishment (Krause et al., 2017). Sleep deprivation can also cause disruptions in working memory, reaction time, response inhibition, visuomotor performance, and motivation (Alhola & Polo-Kantola, 2007).

Common sleep disorders

The classification of sleep disorders is important to better understand and treat symptoms reported by some individuals. Insomnias are some of the more common sleep disorders described as having difficulty initiating and/or maintaining sleep, ultimately having a lot of night wakefulness and insufficient amounts of sleep (Thorpy, 2012). There are also sleep-related breathing disorders such as sleep apnea in which individuals experience episodes during sleep where they stop breathing or have shallow breathing. Another common condition is restless legs syndrome which involves the urge to move the legs and grant temporary relief from unpleasant sensations in the calves and legs (Abad & Guilleminault, 2003). There are many other disorders related to sleep such as parasomnias, hypersomnias, and circadian rhythm sleep disorders (Abad & Guilleminault, 2003).

Neurodevelopmental disorders and sleep

It is not uncommon for children with neurodevelopmental disorders to experience sleep problems such as trouble falling asleep, night awakenings and lessened sleep duration. Attention-Deficit/Hyperactivity Disorder (ADHD) is one of these disorders typically linked to sleep issues in children. Parental reports of sleep problems in children with ADHD include settling difficulties, restless legs syndrome, and variable sleep patterns (Richdale & Schreck, 2009). Trouble with sleep such as excessive daytime sleepiness can also be experienced by adolescents and adults with ADHD. As a result of poor sleep, individuals may experience excessive daytime fatigue, an increase in ADHD symptoms, and changes in mood and behaviour, ultimately impacting daily performance at school or work. (Wajszilber et al., 2018).


Some have reported that the stimulants used in the treatment of ADHD are leading to the sleep disturbances previously listed. The stimulants may be linked to a “rebound effect,” i.e., the return of symptoms which can be sudden and intense after the medication wears off (Konofal et al., 2010). So, the return of symptoms such as restlessness could then be linked with the sleep issues rather than the actual stimulants themselves.


Sleep problems are also seen as comorbid with Autism Spectrum Disorder (ASD) in individuals from childhood to adulthood. The typical concerns reported by parents of children with ASD involve sleep onset, maintenance, and disturbance, which are all typical symptoms of insomnia (Richdale & Schreck, 2009). Adults on the autism spectrum may also experience trouble falling asleep, and frequent waking during the night. It is thought that as insomnia is linked to anxiety and depression, and those with ASD are vulnerable to anxiety and depression, this could also make them more vulnerable to insomnia and other sleep issues (Richdale & Schreck, 2009). Further, children with ASD typically exhibit attachment to routines and sleep issues could arise if routines are not followed, resulting in settling issues. From a biopsychosocial view, these sleep problems may arise due to biological abnormalities altering brain biochemistry or factors at home which are not beneficial to good sleep (Richdale & Schreck, 2009).


In both ADHD and ASD, there are no clear causal factors to the sleep issues exhibited, but rather multiple potential underlying factors. Therefore, the relationship between neurodevelopmental disorders and sleep issues should be examined further to help manage symptoms and promote better sleep from childhood to adulthood.


In all, while we all may struggle sometimes with falling or staying asleep, a consistent lack of sufficient sleep can negatively impact our mental and physical states and may be a sign of an underlying sleep disorder. If you have concerns about your or your child’s sleep, speak to your Family Physician about a referral for a sleep study. Finally, as many studies have found efficient ways to increase both the quantity and quality of the sleep we receive, it is important that we try to maintain good sleep hygiene to maximize all the benefits that sleep has to offer.

Sleep hygiene

Referring to both sleep environment and behaviour, good sleep hygiene can improve both the quality and quantity of sleep someone receives. Some good sleep habits to consider are:

  • Avoiding caffeine, especially at night

  • Sleeping in an environment free from disruptive noise

  • Sticking to a consistent sleep schedule

  • Avoiding long naps or naps in late afternoon/evening

  • Exercising regularly

  • Avoiding light exposure from electronics near bedtime

  • Maintaining low levels of stress before bed

  • Sleeping in a dark and cool environment


Abad, V. C., & Guilleminault, C. (2003). Diagnosis and treatment of sleep disorders: a brief review for clinicians. Dialogues in Clinical Neuroscience, 5(4), 371–388.

Alhola, P., & Polo-Kantola, P. (2007). Sleep deprivation: Impact on cognitive performance. Neuropsychiatric Disease and Treatment, 3(5), 553–567.

Baranwal, N., Yu, P. K., & Siegel, N. S. (2023). Sleep physiology, pathophysiology, and sleep hygiene. Progress in Cardiovascular Diseases, 77, 59–69.

El Shakankiry, H. M. (2011). Sleep physiology and sleep disorders in childhood. Nature and Science of Sleep, 3, 101–114.

Hirshkowitz, M., Whiton, K., Albert, S. M., Alessi, C., Bruni, O., DonCarlos, L., Hazen, N., Herman, J., Katz, E. S., Kheirandish-Gozal, L., Neubauer, D. N., O’Donnell, A. E., Ohayon, M., Peever, J., Rawding, R., Sachdeva, R. C., Setters, B., Vitiello, M. V., Ware, J. C., & Adams Hillard, P. J. (2015). National Sleep Foundation’s sleep time duration recommendations: methodology and results summary. Sleep Health, 1(1), 40–43.

Irish, L. A., Kline, C. E., Gunn, H. E., Buysse, D. J., & Hall, M. H. (2015). The role of sleep hygiene in promoting public health: A review of empirical evidence. Sleep Medicine Reviews, 22, 23–36.

 Konofal, E., Lecendreux, M., & Cortese, S. (2010). Sleep and ADHD. Sleep Medicine, 11(7), 652–658.

Krause, A. J., Ben Simon, E., Mander, B. A., Greer, S. M., Saletin, J. M., Goldstein-Piekarski, A. N., & Walker, M. P. (2017). The sleep-deprived human brain. Nature Reviews. Neuroscience, 18(7), 404–418.

Richdale, A. L., & Schreck, K. A. (2009). Sleep problems in autism spectrum disorders: Prevalence, nature, & possible biopsychosocial aetiologies. Sleep Medicine Reviews, 13(6), 403–411.

Thorpy, M. J. (2012). Classification of Sleep Disorders. Neurotherapeutics, 9(4), 687–701.

Wajszilber, D., Santiseban, J. A., & Gruber, R. (2018). Sleep disorders in patients with ADHD: impact and management challenges. Nature and Science of Sleep, 10, 453–480.

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