We asked five experts: does everyone need eight hours of sleep?

How much sleep we need depends on us as individuals and varies by age
How much sleep we need depends on us as individuals and varies by age Photo: SHUTTERSTOCK

Many of us try to live by the mantra eight hours of work, eight hours of leisure, eight hours of rest. Conventional wisdom has long told us we need eight hours of sleep per day, but some swear they need more, and some (politicians, mostly) say they function fine on four or five.

So is the human brain wired to require eight hours, or is it different for everyone? We asked five experts if everyone needs eight hours of sleep per day.

1. Chelsie Rohrscheib - Neuroscientist - NO

Sleep is absolutely essential, and prolonged sleep deprivation has many detrimental effects on health and lifespan. This is because sleep achieves many critical brain and body maintenance functions that cannot be performed while we are awake.

While humans need, on average, eight hours of sleep each night, the exact length of time it takes to accomplish these sleep functions is highly dictated by an individual's genes.

Some individuals, short sleepers, only need seven hours while others, long sleepers, will need nine. Contrary to popular belief, it's extremely rare for a person to require less than six hours of sleep per night, and those who make this claim about themselves are almost always chronically sleep deprived.

The exception to this rule are individuals with a genetic variant that allows the brain to function more efficiently on less than six hours of sleep, but this is extremely rare and very few people actually have this gene. So it's best to allow your brain to dictate the amount of sleep it needs instead of believing you can get by on less than the average seven to nine hours.

2. Crystal Grant - Sleep expert - NO

Research has shown the amount of sleep needed to function at your best varies between individuals. Most adults between 18-64 years need seven to nine hours sleep per night.

One way to determine the amount of sleep that suits you is to pay close attention to how you feel (mood, energy levels, and overall health). If you are feeling sleepy during the day or needing an extra caffeine boost, you may need to increase the amount of sleep you are getting.

Importantly, do not push sleep to the bottom of your checklist. Make good quality sleep a priority.

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3. Gorica Micic - Sleep expert - NO

Studies show adequate sleep is essential for our overall health and well-being. However, as with nearly every other human variable (such as height, where some of us are taller and others shorter), there are large individual differences in how much sleep each person needs.

Most adults need between seven and nine hours of sleep, but there is a smaller percentage who may need slightly less or more sleep. The grand average of these different individual needs is eight hours, hence this number is often incorrectly portrayed as 'essential'.

The best indicator of whether you're getting enough sleep is how you feel during the day. If you feel sleepy, then you may need more sleep. Our sleep need also declines with age, so newborn infants may need between 12 and 18 hours of sleep whereas older adults may only need six or seven hours.

4. Hailey Meaklim - Psychologist - NO

The saying that everybody needs eight hours of sleep is associated with the industrial revolution – Eight hours labour, Eight hours recreation, Eight hours rest. Genetics, age, medical conditions, environmental and behavioural factors determine how much sleep you need. Some people require more than eight hours and some less.

Certain people function well on less than six hours, and can actually experience insomnia when aiming for eight hours every night. However, short sleepers are rare and current guidelines recommend adults get at least seven hours per night regularly to prevent health problems, such as heart disease or depression.

Sleep is often viewed as a tradeable commodity for work or social events, yet sleep is a vital building block of good health. So, aim for seven or more hours sleep regularly and see your healthcare professional if you have concerns about your sleep or fatigue levels.

5. Stephanie Centofanti - Psychologist - NO

We often hear eight hours as being the magical number to strive for, but in fact, sleep need varies greatly between individuals. Most adults need seven to nine hours of sleep, but as little as six hours may be enough for some people (although this is rare), and up to ten hours may be appropriate for other people.

It's important to know sleep need changes throughout life; children and teens need much more sleep than adults, and as we reach older adulthood we may need slightly less sleep. The amount of sleep we need to be functioning at our best can also change depending on prior sleep history (a period of sleep deprivation, illness or high stress may mean you need more sleep than usual for a little while).

It's important to figure out what works best for you and to prioritise sleep so you are getting enough every night.

Chelsie Rohrscheib is a Postdoctoral fellow and Sleep Specialist at The University of Queensland. Crystal Grant is a PhD Student, Sleep and Chronobiology Laboratory at the University of South Australia. Gorica Micic is a Postdoctoral research fellow at Flinders University. Hailey Meaklim is a Psychologist at RMIT University. Stephanie Centofanti is a Research Fellow, Sleep & Chronobiology Laboratory, Behaviour-Brain-Body Research Centre at the University of South Australia.

This article first appeared on The Conversation.