Would we feel better if we slept a bit more? Possibly – but it isn’t guaranteed. While we know the amount of sleep the average person needs, there is a lot of variation. To get a better idea about how many hours you require – and how and when to get it – let’s start with the basics.
This article is part of special series investigating key questions about sleep. Read more here.
According to the US National Sleep Foundation, a typical adult needs per night, although we begin life needing a lot more – newborns sleep 14 to 17 hours, and this gradually decreases through childhood. Teenagers need about and people over 65 tend to need around 7 to 8 hours. Sex can also be a factor. “There are some studies that show women, on average, need about 20 minutes more than men do,” says at Brunel University of London. And there is evidence that humans, just like many animals, tend to , too.
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Of course, there are exceptions. A rare genetic trait called familial natural short sleep sees individuals habitually going to bed late and waking up early, thriving on just 4 to 6 hours. “We don’t know how prevalent this is,” says at the University of California San Francisco, who has identified involved in the trait, but “it’s a minority”.
Most of us aren’t that lucky, although the occasional disturbed or shortened night doesn’t matter too much. “We are able to get through a night with no sleep and more or less function the next day, and then catch up with it,” says at Northumbria University in Newcastle upon Tyne, UK.
However, regularly going . show that people who regularly get 7 to 9 hours have the lowest risk of dying over the next decade or so, while people who sleep less or more than that have a higher risk of mortality; the longer-term health consequences of sleep deprivation include a higher risk of and cardiovascular problems. Studies also suggest that for most people, sleeping less or more than this . “There are also consequences for how we process emotions,” says Kumari.
But working out how much sleep you personally require is tricky – there is no equivalent of a diagnostic blood test. One useful – if socially challenging – method to determine how much you need is to take a : over a two-week period, go to bed at the same time every night, but don’t set an alarm. What time you naturally wake up can help you figure out your natural rhythms and sleep need. You can also use a sleep tracker or keep a diary, ideally over several weeks, to get a sense of your patterns of sleeping and waking. Noting whether you feel drowsy during the day and when can be useful in determining your personal rhythms.
This will help you figure out your , or what times of day you prefer to sleep or be active. “We have a spectrum, from people who are natural morning larks and people who are natural night owls,” says von Schantz.
Adapting to your chronotype can help keep your sleeping schedule consistent, although researchers acknowledge that this can be a challenge. “The problem with being an evening type is that we live in a society which is designed by larks,” says von Schantz. by going to bed early, but night owls can struggle.
A lot of research has shown that night owls tend to have worse mental health. However, a 37-year follow-up study of Finnish adults found that . Meanwhile, a 2024 study, yet to be peer-reviewed, found that an evening chronotype in itself isn’t a risk factor for psychiatric conditions because by night owls getting less sleep. Evidence also shows that than morning larks, provided they regularly slept 7 to 9 hours.
If you are a night owl but are forced to get up early due to the constraints of daily life, there are ways to try to shift your body clock to a more lark-like schedule. To do this, expose yourself to bright light around 7 am, which will advance your circadian rhythms and help you get to sleep earlier (see “How to shift your circadian clock to beat your jet lag”). As you approach bedtime, avoid bright light as it will delay your body clock. Von Schantz adds that for some people, taking supplemental melatonin, the hormone involved in signalling sleep, can be used to help shift the clock, if timed correctly.
Work on some of these strategies and, regardless of whether you are a lark or an owl, you might greet your alarm with less of a groan – in fact, you might not need one at all.
