Sleep science: How much sleep do you really need?

how much sleep do I need

By now we all know that sleep is important. We spend a third of our lives asleep and we can go for longer without food than we can without sleep. Yet in the 21st century, our lifestyles are becoming less and less compatible with our natural sleep–wake cycle. As we work longer hours, indulge in more screen time, rely more heavily on caffeine and generally lead a more sedentary lifestyle, it is hardly surprising that more than 50% of the population regularly struggle from sleep problems.

But how much sleep should we really be aiming for? Is there an optimum number of hours that everyone should sleep for? In this article we take a look at the recommended hours of sleep we should be getting from birth to old age.



For the first few weeks after birth, babies can sleep form more than 17 hours a day. During this time, a child grows at a faster rate than he or she will during the rest of their lifetime – which requires plenty of rest to facilitate mental and physical growth and development. Lack of sleep at these early stages of life has also been linked to problems with weight – showing its effects by the time they’ve grown to just 3 years old.



Between 3 and 11 months old, a baby should be getting around 12-15 hours sleep. At this age, children can start to get into a rhythm or a set pattern of sleep that is likely to help them fall to sleep more quickly. While a child can appear to be nocturnal during the first few weeks after birth – much to many parents’ dismay – they quickly adapt to a similar sleep–wake cycle as the rest of us by sleeping when it is dark and spending more time awake during the daylight hours.



From 1 year to 4 years old, a typical child will require between 10 and 13 hours sleep. During these early years of life, sleep directly impacts both mental and physical development. Memory, imagination and general cognitive function require children to pass through the full spectrum of sleep phases each night and so it is important that they have a structured bedtime and waking up time.

While it can often be a challenge for parents to implement strict routine on their children, the benefits in terms of mood and progress are widely accepted. Children are also still physically growing rapidly at this stage, which requires a substantial time spent resting.


School children

While many primary school children continue to enjoy 12 hours’ sleep a night for many years, there is a general trend towards fewer hours spent asleep as they get older. By 8 years old, it is common for children to be resting for between 9 and 11 hours a night. This can reduce to 8 hours during teenage years, although many teenagers will also supplement this with naps or longer sleeps at the weekend.

Sleep deprivation during these formative years can lead to lifelong pattern, increasing the risk of mental health problems, poor performance at school, accidents and personal injuries, weight gain and even a greater tendency towards substance abuse.



As adults, we need fewer hours sleep than we did as young children. Achieving between 7 and 9 hours sleep a night is widely considered to be sufficient. This is because our bodies produce less melatonin as we get older – the hormone that regulates sleep and wakefulness. Even though adults need less sleep than children, it is crucial to remember that this is not an excuse to fall into bad habits and leave ourselves sleep deprived.

There is an ever-growing body of research showing that sleep deprivation is linked to lifestyle illnesses and a generally poor quality of life. Not only can it have a direct impact on mood and attention, but also impact on memory and the likelihood of developing illnesses such as dementia and Alzheimer’s later in life.

Poor sleep quality also impacts on appetite, metabolism, stress levels and a broad range of other problems. For these reasons, establishing a good night-time routine, optimising your bedroom for better sleep, and maintaining an active and healthy lifestyle, are just some of the ways you can get the recommended 7-9 hours under your belt each night.

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