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Sleep is an essential biological process, fundamental to restoring our bodies, consolidating memories, and maintaining mental and physical health. Yet, our sleep patterns and needs are not static throughout our lives. From the erratic rest of newborns to the lighter sleep of the elderly, the architecture, duration, and quality of sleep evolve with age. Understanding how and why these changes occur is critical for optimising well-being at every stage of life.

Sleep in Infancy and Childhood

During the earliest years of life, sleep dominates much of the daily cycle. Newborns typically sleep 14 to 17 hours a day, though not in one stretch. Their sleep is polyphasic, meaning it occurs in multiple periods throughout the day and night (Hirshkowitz et al., 2015, National Sleep Foundation). Sleep at this stage is vital for brain maturation and physical growth. According to the American Academy of Sleep Medicine, growth hormone is primarily secreted during deep sleep in children, supporting the importance of adequate rest for healthy development (Paruthi et al., 2016).

As children grow, sleep gradually consolidates into longer nocturnal stretches. By school age, children require approximately 9 to 11 hours of sleep per night. Numerous studies, including one published in *Pediatrics* (2014) by Taveras et al., show that insufficient sleep during childhood can lead to behavioural issues, impaired learning, and even increased risk for obesity. Maximising sleep in childhood thus promotes cognitive development, emotional regulation, and physical health.

Adolescent Sleep: The Challenge of Circadian Shifts

Adolescence brings about profound changes in sleep patterns, characterised by a natural shift in circadian rhythm known as “sleep phase delay.” Teenagers tend to fall asleep and wake up later, a phenomenon rooted in biological changes during puberty (Carskadon et al., 2004, *Sleep*). Despite still requiring 8 to 10 hours of sleep per night, extended screen-time often result in chronic sleep deprivation for many teens. Research published in *The Journal of School Health* (2015) by Owens et al. found that insufficient sleep in adolescents correlate with academic difficulties, increased risk of mood disorders, and impaired driving performance.

These findings have prompted the American Academy of Pediatrics to advocate for later school start times as a public health measure. Monitoring and ensuring screen-time is limited/halted in the hours leading to sleep will usually avoid a poor night’s sleep. Prioritising adequate sleep during these formative years is crucial for academic success, mental health, and the prevention of risky behaviours.

Adulthood: Juggling Sleep and Daily Demands

Young and middle-aged adults typically need 7 to 9 hours of sleep per night, though work, family responsibilities, and social pressures often encroach upon this ideal. The consequences of chronic sleep deprivation in adulthood are well-documented. A study by the Centers for Disease Control and Prevention (CDC, 2016) highlights increased risks for hypertension, diabetes, depression, and workplace accidents among sleep-deprived adults.

Moreover, sleep quality can be as important as sleep quantity. The prevalence of sleep disorders such as insomnia and obstructive sleep apnoea rises in adulthood, affecting both restfulness and long-term health outcomes (Grandner et al., 2017, *Sleep Health*). Maximising sleep in adulthood not only boosts productivity and mood but also acts as a protective factor against chronic disease.

Sleep in Later Life: Light and Fragmented Rest

As we enter older adulthood, sleep patterns undergo further transformation. Older adults often experience lighter, more fragmented sleep, increased nighttime awakenings, and earlier wake times. These changes are partly due to a natural decline in the homeostatic and circadian drive for sleep, as well as age-related medical conditions and medication use (Mander et al., 2017, *Neuron*).

Although older adults may report needing less sleep, studies suggest that the optimal amount remains around 7 to 8 hours per night. Insufficient or poor-quality sleep in the elderly is linked to cognitive decline, increased risk of falls, and diminished immune function (Ohayon et al., 2017, *Sleep Medicine Reviews*). Interventions such as maintaining a consistent sleep schedule, limiting caffeine and screen use, and managing health conditions can help maximise restorative sleep in later life.

The Lifelong Importance of Sleep

As research consistently demonstrates, sleep is a dynamic process that shifts in duration, architecture, and quality as we age. Each stage of life presents unique challenges and vulnerabilities, underscoring the need to prioritise sleep according to our changing biology and circumstances. From supporting the rapid growth of infancy to preserving cognitive health in old age, maximising sleep is not merely a luxury but a necessity for lifelong health.

References:

• Hirshkowitz, M. et al. (2015). National Sleep Foundation’s sleep time duration recommendations: methodology and results summary. *Sleep Health*.
• Paruthi, S. et al. (2016). Recommended amount of sleep for pediatric populations: a consensus statement of the American Academy of Sleep Medicine. *Journal of Clinical Sleep Medicine*.
• Taveras, E. M. et al. (2014). Short sleep duration, obesity, and behavioral problems in preschoolers. *Pediatrics*.
• Carskadon, M. A. et al. (2004). Adolescent sleep patterns, circadian timing, and sleepiness at a transition to early school days. *Sleep*.
• Owens, J. et al. (2015). Insufficient sleep in adolescents: causes and consequences. *The Journal of School Health*.
• CDC. (2016). Short sleep duration among US adults.
• Grandner, M. A. et al. (2017). Sleep disturbance, health outcomes and utilization. *Sleep Health*.
• Mander, B. A. et al. (2017). Sleep and human aging. *Neuron*.
• Ohayon, M. M. et al. (2017). Meta-analysis of quantitative sleep parameters from childhood to old age in healthy individuals: developing normative sleep values across the human lifespan. *Sleep Medicine Reviews*.

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