The amount of sleep necessary for maintaining health is a question that resonates with many. On average, a person will spend about one-third of their life in slumber[1], which underscores its critical role in health and recovery after the day’s events. The right amount of nightly rest is essential, but how much is enough to keep you sharp and well?
Most adults should target 7-9 hours of sleep[2]. This range is generally sufficient to leave someone feeling rejuvenated and prepared for the day. It allows for 4-6 complete sleep cycles, crucial for a balance of restorative sleep and bodily repair.
Keep in mind, individual needs vary, and these figures offer a guideline rather than a one-size-fits-all solution. Your ideal sleep duration might fall somewhere within this window, and personal requirements can evolve with age.
But is it okay to get just 5-6 hours of sleep? Occasionally skimping on the advised 7-9 hours might seem harmless, especially if you don’t feel overly tired. However, the real issue arises when short sleep becomes a regular occurrence.
Frequently missing out on the recommended amount can lead to a ‘sleep debt'[3], the total lack of sufficient sleep. This deficit, even over a short period, can manifest in several immediate drawbacks, such as:
- Morning lethargy: Waking up can become more difficult, with grogginess and potential dizziness as your body craves more rest to “repay” the sleep debt.
- Persistent weariness: You might experience ongoing fatigue due to missing out on deep sleep, which is vital for physical restoration.
- Memory issues: Adequate sleep is crucial for memory consolidation. Without it, you might find yourself more forgetful than usual.
- Decreased performance: Carrying a sleep debt can affect your work, mood, and alertness levels, making it harder to concentrate and perform effectively.
The recommended sleep duration for adults, aged 18 to 65, is typically 7-9 hours, but sleep requirements do evolve with age, particularly for the very young and the elderly.
In essence, infants and children require considerably more sleep than other age groups, while seniors often need less.
From infancy, where sleep dominates the day, to older age, where a retiree might need only a handful of hours, sleep patterns shift dramatically with age.
During our younger years, as our bodies and minds grow rapidly, rest is crucial for recovery and assimilation of daily experiences and new knowledge[6].
Examining the sleep needs during various life stages:
- Newborns
- Babies
- Children
- Teenagers
- Adults
- Elderly individuals
For newborns (0–3 months), the recommended amount of sleep is between 14–18 hours, though it can range from 10.5–20 hours.
Newborns have yet to develop a consistent sleep-wake cycle, resulting in a polyphasic sleep pattern with multiple naps of 2–4 hours throughout the day and night.
Their sleep cycle includes a higher proportion of REM sleep, which is essential for brain development. Interestingly, they are more active during REM sleep than adults.
For babies aged 4–11 months, the sleep recommendation is 12–16 hours, but it can vary between 10–19 hours.
By the time a baby reaches their first birthday, their sleep patterns start to mirror that of adults, although they still require considerably more rest. Typically, a one-year-old might sleep for 10–12 hours at night and have one or two daytime naps totaling 1–2 hours.
Even though they continue to experience a significant amount of REM sleep, toddlers begin to display adult-like stillness during this restorative sleep phase.
Children’s sleep needs gradually diminish as they grow:
- From 1–2 years old, it’s advised they get 11–15 hours of sleep, although anywhere from 9–17 hours may be appropriate.
- For those aged 3–5 years, 10–14 hours are recommended, though 8–15 hours might suffice.
- Children 6–13 years old should aim for 9–12 hours, but some may need as much as 7–13 hours, depending on their individual development.
As children age, they nap less, but adequate sleep remains crucial. Insufficient sleep can lead to problems with weight, mental health, behavior, and cognitive abilities[7].
Toddlers might still have daytime naps, gradually transitioning to one shorter nap. Preschoolers may continue to nap daily, but the length and necessity of these naps decrease.
During the 6–13 year age range, while the general trend is toward needing less sleep, individual growth patterns may result in varied sleep requirements.
Teenagers between 14–17 years should get 8–11 hours of sleep, though some may need anywhere from 7–12 hours.
As adolescents undergo rapid mental, physical, emotional, and social development, they require more rest, similar to younger children. Yet, studies show that 73% of teenagers don’t meet their sleep needs[8], often due to increased academic and social pressures.
To address these challenges, some families and educational institutions are rethinking schedules to include napping opportunities and later school starts.
Upon reaching adulthood, sleep patterns stabilize:
- Young adults aged 18–25 should aim for 7–10 hours of sleep, though 6–12 hours might be adequate during the transition out of the teenage years.
- Adults 26–64 years old are generally advised to get 7–9 hours, but 6–11 hours could be acceptable for some.
Finally, seniors over 65 typically need 7–9 hours of sleep, with a broader range of 5–10 hours being acceptable as sleep patterns can alter with age.
As adults advance into their senior years, the amount of sleep recommended doesn’t change; however, actually securing those hours can become more challenging.
Research indicates that nearly half of older adults encounter difficulties in achieving the recommended nightly sleep[9]. This can be attributed to a multitude of factors.
One significant issue is that sleep tends to be lighter in older age, leading to easier disruptions compared to the deeper sleep of younger individuals.
Additionally, it may take seniors longer to fall asleep, often more than 30 minutes. Compounding this, they may face health conditions like restless leg syndrome (RLS), periodic limb movement disorder (PLMD), or the effects of medications, all of which can interrupt sleep.
What are the implications of mismatched sleep durations? Ideally, everyone would obtain the optimal amount of rest corresponding to their life stage. But when the amount of sleep you’re getting is misaligned, there could be lasting impacts on health and well-being.
A disrupted sleep pattern can manifest from both insufficient sleep and excessive sleep.
Insufficient Sleep: Lack of adequate rest can weaken your immune system, leaving you fatigued, more likely to gain weight, and susceptible to mental health issues such as anxiety and depression. It also raises the risk of serious health conditions like diabetes and cardiovascular disease.
Excessive Sleep: Conversely, too much sleep isn’t beneficial either. It can lead to weight gain, headache disorders including migraines, muscle soreness, spinal issues, and a thrown-off internal clock. Excessive sleep, similar to too little, can increase the likelihood of developing serious health conditions like diabetes and heart disease.
Can we adjust to less sleep over time? The notion that one can adapt to functioning on less than 7–9 hours of sleep is a common misconception. There’s a small percentage of people who can operate normally on 6 or fewer hours, possibly due to genetic factors[10], but this is not the norm.
Often, individuals who believe they’re doing fine on limited rest may not realize they’ve simply grown accustomed to the downsides of sleep deprivation[11].
Their bodies require the same rest as anyone else; they’ve merely adjusted to operating at a diminished capacity. This decline in performance can be so gradual that it goes unnoticed.
Factors Influencing Sleep Duration If you or a household member struggles to get the recommended amount of sleep, it’s likely due to a disruptive factor.
Common disruptors include:
Sleep disorders: Any sleep disorder can interfere with getting enough rest, whether it’s insomnia, sleep apnea, RLS, or another condition. Conditions like hypersomnia and narcolepsy can cause excessive daytime sleepiness.
Health issues: Non-sleep-specific health problems like asthma, allergies, hyperthyroidism, or acid reflux can interfere with a full night’s sleep.
Mental health: Anxiety, stress, and depression can significantly disrupt sleep. Relaxing activities before bed can help, but persistent issues should be addressed with a doctor.
Irregular sleep schedules: Deviating from a regular sleep routine can confuse your circadian rhythm, making it harder to sleep well.
Diet: Consuming sugary, caffeinated, or alcoholic items before bed can hinder sleep. Large meals and fluids right before sleep can also be disruptive.
Environmental noise and disturbances: External noise or internal disruptions from family, pets, or partners can affect sleep.
Napping: Daytime naps, especially long or late ones, can disrupt nightly sleep patterns.
Bedroom conditions: A room that’s too hot, too cold, or not dark enough can prevent quality sleep.
Uncomfortable sleep surfaces: Old or uncomfortable mattresses and bedding can hinder sleep and cause physical discomfort.
Pregnancy: Pregnant individuals may need more sleep due to hormonal changes and physical demands.
Past sleep deprivation: If you’ve recently resolved sleep disruptions, you might still feel tired as your body recovers from previous lack of sleep.
Poor sleep quality: Disruptions or other issues that prevent full sleep cycles can lead your body to demand more sleep to compensate.
It’s also crucial to note that additional factors such as pregnancy can alter your sleep needs due to bodily changes.
If you struggle with sleep, consider consulting our guide on common sleep issues and disorders for more information.
