Can you train yourself to need less sleep?

You can train yourself to feel less sleepy on less sleep — this is called adaptation to sleep restriction. But this does not mean your body is functioning optimally on less sleep. Objective cognitive performance continues to deteriorate even as subjective sleepiness stabilises. The perception of functioning normally on little sleep is one of the most dangerous cognitive distortions related to sleep deprivation. The evidence is clear that consistently sleeping below 7 hours carries health consequences that are not mitigated by adaptation.

Is it possible to sleep too much?

Consistently sleeping more than 9–10 hours as an adult — particularly if feeling unrefreshed despite long sleep — should be investigated rather than simply accepted. Long sleep duration is associated with increased cardiovascular disease risk and mortality in population studies, though this is largely confounded by the fact that people who sleep very long often do so because of underlying illness (depression, sleep apnea causing fragmented non-restorative sleep, heart failure, or other conditions). Hypersomnia is itself a clinical condition warranting evaluation.

Do I really need more than 6 hours?

The probability that you are one of the rare individuals (<3% of the population) who can maintain health and performance on 6 or fewer hours without consequence is low. The more likely explanation for feeling functional on 6 hours is adaptation to chronic sleep deprivation — your subjective sense of sleepiness has adjusted, but objective impairment persists. A systematic review and meta-analysis found that sleeping 6 hours per night is associated with a 13% higher mortality risk compared to 7–9 hours, independent of other lifestyle factors.

How does sleep need change with age?

Sleep need is substantially higher in childhood and adolescence (supporting rapid neurodevelopment) and gradually stabilises in adulthood. The ability to obtain consolidated sleep — rather than the biological need — decreases with age: older adults need approximately as much sleep as younger adults but have more difficulty getting it in a single uninterrupted block. This reduced sleep efficiency in older adults should not be interpreted as reduced sleep need.

How Much Sleep Do You Actually Need? | whataresleepdisorders.com

Q: How does sleep need change with age?

Sleep need is substantially higher in childhood and adolescence (supporting rapid neurodevelopment) and gradually stabilises in adulthood. The ability to obtain consolidated sleep — rather than the biological need — decreases with age: older adults need approximately as much sleep as younger adults but have more difficulty getting it in a single uninterrupted block. This reduced sleep efficiency in older adults should not be interpreted as reduced sleep need.

"How much sleep do I really need?" This question has a clear scientific answer — but a considerable gap exists between what research shows and how most people actually live. Understanding sleep need is not about hitting an arbitrary number; it is about understanding why inadequate sleep carries real health consequences, and why the widespread social tolerance of insufficient sleep is one of the most significant and preventable public health issues of our time.

Official Recommendations: Sleep Requirements by Age

The American Academy of Sleep Medicine (AASM) and the Sleep Research Society have published consensus recommendations based on a systematic review of the health literature. These represent the total sleep per 24-hour period (including naps for younger children):

Newborns (0–3 months): 14–17 hours
Infants (4–12 months): 12–16 hours
Toddlers (1–2 years): 11–14 hours
Preschoolers (3–5 years): 10–13 hours
School-age children (6–12 years): 9–12 hours
Teenagers (13–18 years): 8–10 hours
Adults (18–60 years): 7 or more hours
Adults (61–64 years): 7–9 hours
Older adults (65+ years): 7–8 hours

The adult recommendation of 7 or more hours is endorsed by the CDC, the National Institutes of Health, the World Health Organization, and the American Medical Association. Consistently sleeping fewer than 7 hours per night is associated with an increased risk of obesity, type 2 diabetes, hypertension, cardiovascular disease, depression, reduced immune function, and premature mortality.

Why There Is a Range: Individual Sleep Variation

Sleep need is not identical for every adult. The 7–9 hour range for adults reflects genuine biological variation — some people genuinely function optimally on 7 hours, others require closer to 9. This is largely determined by genetics, particularly genes involved in sleep pressure regulation and slow-wave sleep intensity.

However, this range has limits. The portion of the population who can genuinely maintain optimal health and performance on 6 or fewer hours of sleep — the "short sleepers" — is estimated at less than 3% of the population and is associated with specific mutations in the DEC2 and ADRB1 genes. The vast majority of people who report needing only 5–6 hours of sleep have not discovered that they are a genetic short sleeper — they have become habituated to chronic sleep deprivation and no longer accurately perceive their own impairment.

This last point is clinically important: one of the most consistent and counterintuitive findings in sleep research is that people who are chronically sleep-deprived substantially underestimate their own impairment. Subjective sleepiness ratings stabilise (people stop feeling as sleepy as they actually are) while objective cognitive performance continues to deteriorate. You cannot reliably self-assess sleep deprivation by how tired you feel.

Sleep Quality vs. Sleep Quantity

Total hours of sleep is only part of the picture. Eight hours of severely fragmented sleep — interrupted by sleep apnea, noise, pain, or frequent wakings — does not provide the same restoration as eight hours of consolidated, appropriately staged sleep. Sleep quality encompasses:

Sleep efficiency: The proportion of time in bed actually spent asleep (normal is above 85%)
Sleep continuity: The degree to which sleep is uninterrupted by arousals and awakenings
Sleep architecture: Appropriate proportions of N1, N2, N3 (slow-wave), and REM sleep, and cycling through them in the normal sequence
Perceived restorativeness: Whether you wake feeling refreshed

Someone with untreated sleep apnea may spend 9 hours in bed but have such severely fragmented sleep that their effective restorative sleep is equivalent to 3–4 hours. This is why total time in bed is an incomplete measure — the quality and architecture of sleep matter enormously.

Signs You Are Not Getting Enough Sleep

Several reliable indicators suggest that your current sleep is inadequate for your biological need:

Needing an alarm to wake up (inability to wake spontaneously at a consistent time)
Falling asleep within minutes of your head hitting the pillow (extreme sleep pressure — normal sleep onset takes 10–20 minutes)
Difficulty waking in the morning despite hours of sleep
Needing large amounts of caffeine to function or to stay alert
Falling asleep unintentionally during passive activities (reading, watching television, meetings)
Significant daytime mood changes, irritability, or emotional reactivity not otherwise explained
Impaired concentration and working memory
Increased appetite, particularly for high-calorie foods
Waking without feeling refreshed despite adequate time in bed

The "sleep vacation test" is a useful self-assessment: on a holiday with no obligations, no alarm, and no schedule pressure, how long do you sleep spontaneously? If you sleep significantly longer than your habitual schedule (e.g., 10 hours when you normally sleep 6.5), this suggests you are carrying chronic sleep debt.

The Myth of Catching Up on Sleep

"Binge sleeping" on weekends to compensate for a short-sleep working week is a widely practised strategy with significant limitations:

Recovery sleep on weekends does partially restore subjective alertness and some cognitive measures
However, it does not fully reverse all effects — metabolic dysregulation from chronic sleep restriction is not fully corrected by weekend recovery sleep in some studies
Weekend lie-ins shift the circadian clock later, creating social jet lag that makes Sunday night sleep harder and Monday morning more difficult
The cycle of under-sleeping on weekdays and over-sleeping on weekends creates ongoing circadian instability
The most health-protective strategy is maintaining adequate sleep on all nights, not accumulating debt and attempting periodic repayment

What Happens During Sleep: Why the Hours Matter

Understanding why sleep duration matters requires understanding what sleep does:

First half of the night (hours 1–4): Dominated by slow-wave (deep) sleep — the most physically restorative stage. Growth hormone release, tissue repair, immune consolidation, and metabolic regulation predominantly occur here. Cutting sleep short truncates this phase relatively less than the second half.
Second half of the night (hours 5–8): Dominated by REM sleep — the stage essential for emotional memory processing, creative thinking, and mood regulation. Waking early (the most common form of insufficient sleep) dramatically reduces REM. People who sleep 6 hours lose approximately 70% of their REM sleep compared to those sleeping 8 hours.

This asymmetry explains why sleep restriction preferentially harms emotional regulation, creativity, and mental health — the functions most dependent on late-night REM — even before physical restoration is compromised.

When to Speak With a Doctor

If you are consistently getting fewer than 7 hours of sleep per night and feel this is simply your normal, it is worth discussing with a doctor — particularly if you have any of the signs of chronic sleep deprivation above, or any cardiovascular, metabolic, or mental health conditions. Treating sleep as a health priority rather than a negotiable lifestyle variable is one of the highest-return investments you can make in your long-term health.

References

Watson NF, et al. Recommended amount of sleep for a healthy adult: a joint consensus statement. Journal of Clinical Sleep Medicine. 2015;11(6):591–592.
Cappuccio FP, et al. Sleep duration and all-cause mortality: a systematic review and meta-analysis. Sleep. 2010;33(5):585–592.
Van Dongen HPA, et al. The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions. Sleep. 2003;26(2):117–126.
Walker MP. Why We Sleep. Allen Lane; 2017.
Centers for Disease Control and Prevention. How Much Sleep Do I Need? 2022.