How Many Hours of Sleep Do You Need Per Night?

Australia Today

How Australians are tracking

Australians like to think we're a well-rested nation. The reality is more complicated.

According to the Australian Bureau of Statistics, adults who wore activity trackers in 2023 slept an average of 7 hours and 36 minutes a night — but the averages hide a meaningful split between people who consistently hit healthy sleep targets and those who fall short. Source 2: Australian Bureau of Statistics (2024)

7h 36m

Average sleep per night for Australian adults (ABS, 2023)

Source 2: Australian Bureau of Statistics (2024)

26.9%

of Australian adults get less than the recommended 7 hours a night

Source 3: Sleep Health (2017)

9.1%

of Australian adults sleep fewer than 6 hours a night

Source 2: Australian Bureau of Statistics (2024)

By Age Group

The real numbers, by age

The National Sleep Foundation's evidence-based recommendations are the most widely cited targets in sleep medicine. Your ideal duration falls within a range — and where you sit in that range depends on genetics, activity levels, and individual recovery needs. Source 1: Sleep Health (2015)

Age group	Recommended sleep	What to know
Newborns (0-3 months)	14-17 hours	Sleep is broken into short bursts around feeding
Infants (4-11 months)	12-15 hours	Includes daytime naps; longer nights start emerging
Toddlers (1-2 years)	11-14 hours	One or two naps still developmentally important
Preschoolers (3-5 years)	10-13 hours	Most stop napping by age five
School-age (6-13 years)	9-11 hours	Critical for memory, mood and growth
Teenagers (14-17 years)	8-10 hours	Body clock shifts later — early school starts are tough
Adults (18-64 years)	7-9 hours	The sweet spot for most working-age Australians
Older adults (65+)	7-8 hours	Sleep often becomes more fragmented but the need remains

The Stakes

What happens when you fall short

The consequences of chronic sleep loss aren't just feeling groggy. They're measurable in clinical studies, blood tests, and long-term health outcomes. Here's what the research actually shows.

4.2×

Higher cold risk under 6 hours

In a landmark UCSF study, people sleeping 5-6 hours a night were 4.2 times more likely to catch a cold after exposure to the rhinovirus than those sleeping more than 7 hours.

Source 4: Sleep (2015)

Memory loss

Restricted sleep impairs learning

A 2024 meta-analysis of 39 studies and 1,234 participants found that sleeping 3-6.5 hours significantly disrupts memory formation — and weekend "catch-up sleep" doesn't fully undo the damage.

Source 5: Neuroscience & Biobehavioral Reviews (2024)

Heart strain

Less than 6 hours raises blood pressure

Sleep deprivation disrupts your autonomic nervous system, elevating sympathetic activity. People who routinely sleep under 6 hours show significantly higher rates of hypertension and cardiovascular disease.

Source 6: Frontiers in Neurology (2025)

14-34%

Higher mortality risk from imbalanced sleep

A 2025 meta-analysis confirmed Cappuccio's landmark earlier work: people sleeping too little or too much show a 14-34% increase in all-cause mortality risk compared with those hitting the recommended range.

Source 7: GeroScience (2025)

Sleep Through History

Have we always slept this way?

Here's a question almost nobody thinks to ask: is the way you sleep right now — one solid block of 7 to 9 hours, in a dark bedroom, between roughly 11pm and 7am — actually the way humans have always slept?

The honest answer from historians and sleep scientists is no. The "one consolidated sleep" model is, in evolutionary terms, very new. And looking at how humans used to do it (and how some still do) helps explain why the 3am wake-up that feels so frustrating might not be a sign that anything is wrong with you.

The big idea: Modern monophasic sleep is partly a product of artificial lighting, industrial work schedules, and electrified evenings. Before all that, the dominant pattern in Western societies wasn't one long block — it was two.

Four patterns, four eras

Here's how human sleep has been organised across history and across cultures. Each visualisation represents a single 24-hour day, with the darker bars showing when sleep takes place.

Pre-1800s · Pre-industrial

(Segmented sleep)

Documented by historian Roger Ekirch in over 2,000 references — from Homer's Odyssey to 17th-century diaries — describing two distinct sleeps separated by an hour or two of quiet wakefulness around midnight.

First sleepRoughly 9pm to midnight — three to four hours of deep "dead sleep" after dusk.
Second sleepRoughly 1am or 2am to dawn — a lighter sleep until first light. The gap between, "the watch," was used for prayer, writing, or visiting neighbours.

Total sleep ~7-8 hours

Evidence: Strong historical record Source 8: American Historical Review (2001)

Industrial era to today

(Monophasic sleep)

The pattern most readers will recognise — and the historical exception, not the rule. Ekirch argues it only became dominant after street lighting and the industrial workday created economic incentives to compress sleep.

One consolidated sleepRoughly 11pm to 7am — a single uninterrupted block of 7 to 9 hours overnight.
No daytime sleepThe day belongs entirely to waking life. No naps, no siesta, no waking "watch" in the middle of the night.

Total sleep 7-9 hours

Evidence: Strong scientific support Source 8: American Historical Review (2001)

Mediterranean & Latin cultures

(Siesta biphasic)

Common in Spain, Greece, Italy and much of Latin America. The only biphasic pattern with both cultural precedent and modern scientific support — short afternoon naps improve alertness without disrupting night sleep.

The siestaA 30 to 90 minute nap in the early afternoon, typically after lunch when alertness naturally dips. Helps restore focus for the rest of the day.
Core night sleepA slightly shorter overnight block of around 7 hours. The nap takes the edge off, but doesn't replace nighttime rest.

Total sleep ~8-8.5 hours

Evidence: Culturally validated

Modern internet experiment

(Polyphasic)

The most extreme of the modern polyphasic schedules. Despite enthusiastic forum communities, the science is firmly against it — the Sleep Foundation reports no peer-reviewed evidence these schedules are sustainable or safe.

Six 20-minute napsSpaced every four hours, day and night. The theory is the brain learns to reach REM faster — but the research doesn't back this up.
No core sleepTotal sleep drops to just 2 hours per day. Naps under 30 minutes don't allow deep or REM stages, leaving the body chronically deprived.

Total sleep 2 hours

Evidence: Not supported · High risk Source 10: Sleep Foundation

The science actually backs up the history

The most striking thing about Ekirch's historical research is that it's been independently confirmed by modern sleep biology. In a now-famous 1992 study at the U.S. National Institute of Mental Health, sleep researcher Thomas Wehr put healthy adults in a controlled environment with only 10 hours of daylight per day for a month — roughly the light conditions of a preindustrial winter.

The first few nights, participants slept around 11 hours (catching up on chronic sleep debt). By week four, something remarkable happened: their sleep naturally split into two roughly equal bouts of four hours, separated by one to three hours of calm wakefulness — almost exactly the pattern Ekirch described from preindustrial diaries. Under the right lighting conditions, the segmented sleep pattern emerged on its own. Source 9: Journal of Sleep Research (1992)

The honest takeaway: if you find yourself wide awake at 3am for an hour, you're not broken — you may simply be expressing a sleep pattern your great-great-grandparents would have recognised as normal. The fix isn't to panic, it's to stay calm, keep the lights low, and let yourself drift back. But the modern productivity culture of "hacking" sleep down to two or four hours through micro-naps is doing exactly the opposite of what the evidence supports. Total sleep matters. Hit the 7-9 hour range, in whatever arrangement actually fits your life, and you're on solid scientific ground.

Practical Guide

How to actually hit your number

The goal isn't a perfect routine — it's a slightly better one. Three evidence-backed changes you can start tonight.

01

Anchor your wake-up time

Even on weekends. Australian research on older adults found that bed and wake times varying by more than 60 minutes were strongly linked with sleeping less than 7 hours a night. Consistency is the single most underrated sleep variable.

Source 11: Clinical Gerontology (2017)

02

Engineer your environment

Dark, cool, and quiet are the three non-negotiables. Light leaking through curtains, partner noise, traffic, and bedroom temperature are the most common reasons Australians wake at 4am and can't get back to sleep — and all three are fixable.

03

Put your phone to bed first

The Sleep Health Foundation's 2016 national survey found that 26% of Australians who used the internet most or every night just before bed reported frequent sleep difficulties or daytime impairment. A 30-minute pre-bed wind-down is the highest-leverage change you can make.

Source 3: Sleep Health (2017)

Products that help you protect the hours

None of these will sleep for you — but each one removes a barrier between you and the rest you've earned. These are the categories Australian customers reach for most often when they're trying to close the gap on their sleep target.

Block light

Sleep masks

Early Australian sunrises and partner reading lamps don't stand a chance against a properly contoured mask. Darkness triggers melatonin production — your body's natural sleep signal.

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Mask noise

White noise machines

Traffic, snoring, noisy neighbours, sirens. White, pink and brown noise machines mask sudden interruptions and create a consistent sound environment that helps you stay asleep.

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Audio for side sleepers

Sleep headphones

Bluetooth headband-style sleep headphones from SleepPhones and others let you fall asleep to music, podcasts or guided meditation without bulky earbuds digging in when you roll over.

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Neck and head support

Memory foam pillows

The wrong pillow height is one of the most overlooked causes of restless sleep. A contoured memory foam pillow that matches your sleep position keeps your neck neutral all night.

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Pressure relief

Mattress toppers

If your mattress feels too firm, too soft, or just tired, a quality topper can transform your sleep surface overnight — and at a fraction of the cost of replacing your mattress.

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Temperature control

Quilts & bedding

Cool, dark, and quiet — temperature is the most overlooked of the three. Seasonal quilts, breathable bamboo sheets and natural fibres help you regulate body temperature through the night.

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Sleep is the foundation everything else is built on

Hitting your sleep number isn't about chasing perfection. It's about giving your body the time it needs to repair, your brain the time it needs to consolidate, and your immune system the time it needs to defend you. The people who sleep well don't just live longer — they live brighter.

Sharper mornings
Steadier moods
More energy for the things that matter
Your number is somewhere between 7 and 9.
Find it
Protect it

Everything else gets easier from there.

Scientific References

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.
Australian Bureau of Statistics. (2024). Measured physical activity and sleep, 2023. ABS.
Adams, R. J., Appleton, S. L., Taylor, A. W., Gill, T. K., Lang, C., McEvoy, R. D., & Antic, N. A. (2017). Sleep health of Australian adults in 2016: results of the 2016 Sleep Health Foundation national survey. Sleep Health, 3(1), 35-42.
Prather, A. A., Janicki-Deverts, D., Hall, M. H., & Cohen, S. (2015). Behaviorally assessed sleep and susceptibility to the common cold. Sleep, 38(9), 1353-1359.
Crowley, R., Alderman, E., Javadi, A.-H., & Tamminen, J. (2024). A systematic and meta-analytic review of the impact of sleep restriction on memory formation. Neuroscience & Biobehavioral Reviews, 167, 105929.
Zhang, S., Niu, X., Ma, J., Wei, X., Zhang, J., & Du, W. (2025). Effects of sleep deprivation on heart rate variability: a systematic review and meta-analysis. Frontiers in Neurology, 16, 1556784.
Ungvari, Z., Fekete, M., Varga, P., Fekete, J. T., Lehoczki, A., Buda, A., Szappanos, Á., Purebl, G., Ungvari, A., & Győrffy, B. (2025). Imbalanced sleep increases mortality risk by 14-34%: a meta-analysis. GeroScience, 47(3), 4545-4566.
Ekirch, A. R. (2001). Sleep we have lost: pre-industrial slumber in the British Isles. American Historical Review, 106(2), 343-386. See also Ekirch, A. R. (2005). At Day's Close: Night in Times Past. W. W. Norton.
Wehr, T. A. (1992). In short photoperiods, human sleep is biphasic. Journal of Sleep Research, 1(2), 103-107.
Suni, E., & Dimitriu, A. (2024). Polyphasic Sleep: Benefits and Risks. Sleep Foundation. Reviewed by Dr. Alex Dimitriu, board-certified in Sleep Medicine.
Paterson, J. L., Reynolds, A. C., & Dawson, D. (2017). Sleep schedule regularity is associated with sleep duration in older Australian adults: implications for improving the sleep health and wellbeing of our aging population. Clinical Gerontology, 41(2), 113-122.