The importance of a good night’s sleep

Not only do our sleep requirements change through life, but our ancestors had very different sleeping patterns and coped perfectly well. So how many “Zs” do we actually need, and how can we get them?  

7 minutes

  • New research shows that deep sleep washes away toxins that can lead to Alzheimer’s
  • In the long winter nights, our ancestors commonly slept in “two shifts” 
  • Top tips for a good night’s sleep

We all know how great it feels to wake up after a sound sleep: refreshed, full of energy and ready for the day ahead.

However, getting that amount and quality of sleep can prove elusive. According to 2017 research[1] amongst 5,000 people, carried out on behalf of a UK body called “The Sleep Council”, almost a third of us (30%) report getting a poor sleep most nights. The top three reasons? Stress and worry (45%), partner disturbance (25%) and noise (20%).

What’s more, our sleeping hours appear to be waning: 12% of us now have less than five hours a night compared to 7% in 2013. [1]

Why age matters in sleep

We’re all different as individuals, with some people famous for their ability to get by on very little sleep. So how much sleep is “enough”?

One expert on the subject is Ana Noia, a senior clinical physiologist in neurophysiology and sleep at Bupa Cromwell Hospital; and, according to her, age is a big factor. She says that newborns require 16 - 18 hours a day, two-year-olds need 11 - 13 hours and even teenagers require eight to ten hours. The figure continues to reduce during our adult years, so that by the age of 65, five to seven hours a night will suffice although she still recommends having between seven to eight hours a night.

Sleep patterns also change with age, with older people tending to go to bed (and wake) earlier. Some fascinating research published in 2017 by The Royal Society suggests that, in our past, a tribe would share “sentinel” duties at night to counter the risk of attacks, with older “up with the lark” members taking on the early morning shifts – and that this behaviour can still be observed in today’s hunter-gatherer communities. [2]

While the reasons why we need to sleep are well understood (primarily for our brains to process experiences and our bodies to repair worn or damaged tissues) it’s perhaps ironic that a number of medical conditions can actually impair our ability to sleep in the first place – such as arthritis, back pain, diabetes and prostate problems.

But a sound night’s slumber is just as important, whatever our age: research published in Science Advances earlier this year shows that it “washes away” waste materials from our brain – and that poor or inadequate sleep leaves these behind, potentially leading to the build-up of materials which can lead to Alzheimer’s. According to the paper’s author Maiken Nedergaard, co-director of the Center for Translational Neuromedicine at the University of Rochester Medical Center, “The deeper the sleep the better”.

So how normal is “normal”?

Intriguingly, what we now regard as a “good night’s sleep” is actually a relatively modern construct. Prior to industrialisation, fixed working hours and artificial lighting, it was quite normal for people to go to bed not long after dusk, follow a two-sleep (bi-phasic) pattern with a long break in between and then wake at dawn.

In studies of African and South American tribes, and "second" sleeps are commonly described, and this was backed by research in the 1990s by Dr Thomas  Wehr who imposed 14-hour “nights” on a study group; eventually they naturally adjusted to a two-shift sleep pattern with a one to three hour waking interval.

So perhaps we should be worrying far less if we DO get a break in our nightly sleeping pattern.

Preparing for sleep

It’s generally recognised that modern life is adversely impacting on our shut-eye: not just increased light and noise pollution, but the blue light emitted from tablet and phone screens which can inhibit the production of melatonin… the hormone that tells our bodies when it’s time to sleep. Fortunately, it seems that we’re getting wise to this: the number of people using technology in the bedroom has actually declined since 2013 with those checking emails down from 14 to 6%, although those going on social media showed a small rise from 8 – 9% [1].

Medical experts who specialise in helping people overcome insomnia will always focus on encouraging the body and mind to relax as we prepare for sleep – and even obvious things like having had sufficient exercise during the day, having a comfortable bed, getting the temperature of the room right, not eating a large meal too soon beforehand and having a set, calming bedtime routine can be enormously helpful.

Conversely, while a “nightcap” is assumed to relax us, excessive amounts of alcohol can actually have an adverse effect. [3]

A pre-bed bath or shower can prove a great way to wind down. A 1999 study by Gunma University in Japan concluded that “a bath before sleep enhances the quality of sleep, particularly in the elderly”.

And while many of us rely on a book to get into the mood for sleep, the Sleep Report for 2017 [1] found that growing numbers are turning to relaxing music (up from 17% in 2013 to 24% in 2017) while meditation has also increased in popularity – from 8% to 12%.

Emptying our minds of the “stuff” that clogs up our days is patently a key way to relax and doze off: perhaps the old-fashioned advice to count sheep is not such a bad idea after all…


[1] The Sleep Council, 2017. The Great British Bedtime Report,

[2] David R. Samson , Alyssa N. Crittenden , Ibrahim A. Mabulla , Audax Z. P. Mabulla  and Charles L. Nunn, 2017. Chronotype variation drives night-time sentinel-like behaviour in hunter–gatherers, The Royal Society Publishing

[3] Denise Mann, 2013. Alcohol and a Good Night's Sleep Don't Mix, WebMD