Many successful people claim they need only a few hours of sleep each night.
But the lack of sleep is linked to health problems, including diabetes, depression, and heart disease. It impacts longevity and increases the risk of Alzheimer's.

The lack of sleep

A recent study reveals that our bodies use the REM period of sleep - the dreamless and deep part - to cleanse our brain of toxins. 
When the neurons in the brain quiet down, they need less oxygen and blood. At that point, cerebrospinal fluid - the liquid surrounding the brain - floods the space, cleaning the brain of potentially toxic chemical byproducts.

Sleep washes the brain

An increasing number of people are sleep-deprived. Being always busy contributes to a cycle of sleeplessness that impacts our health and holds us back from achieving.
A 2017 study found that a worker sleeping less than six hours a night loses around six working days a year to absenteeism.

Lack of sleep affects the economy

<img alt="World Economic Forum" src="https://www.weforum.org/assets/logo-ddc1cc485dc7b53710927fa8446c3260a3f026b25924f28c1e58fa996be66db1.svg" width="78" height="48"><figure><picture><img alt="Sleeping woman bed nighttime " src="https://assets.weforum.org/article/image/large_rr2WCEuhGZ0MEP8xgN0BAUJAjjjqql0i1yt7Dz-oMEc.jpg" width="743" height="321"></picture><figcaption dir="auto">Lack of sleep has been linked to diabetes, depression and heart disease.
Image: Gregory Pappas/Unsplash</figcaption></figure><div>13 Dec 2019</div><UL><LI>More people suffer from a lack of sleep, with potential harmful results</LI><LI>Deep, dreamless sleep clears away brain toxins, scientists believe</LI><LI>Lack of sleep inflicts big costs on the economy</LI></UL>From technology entrepreneur <a href="https://www.standard.co.uk/lifestyle/health/11-successful-people-who-get-by-on-hardly-any-sleep-a3598856.html" rel="noopener" dir="ltr">Elon Musk</a> to former Yahoo! <a href="https://www.forbes.com/sites/alicegwalton/2015/11/13/the-sleep-habits-of-highly-successful-people-infographic/#23300e436d7f" rel="noopener" dir="ltr">CEO Marissa Mayer</a> and business mogul <a href="https://www.forbes.com/sites/alicegwalton/2015/11/13/the-sleep-habits-of-highly-successful-people-infographic/#23300e436d7f" rel="noopener" dir="ltr">Richard Branson</a>, there is no shortage of successful people claiming to need just a few hours’ sleep each night. But while many of them wear their sleeplessness like a badge of pride, scientists woke up to the power of a good night’s sleep some years back. And now they have worked out just how the brain works its magic.The brain-washing machineLack of sleep has been linked to a host of health issues including <a href="https://www.nhs.uk/live-well/sleep-and-tiredness/why-lack-of-sleep-is-bad-for-your-health/" rel="noopener" dir="ltr">diabetes, depression and heart disease</a>, and is known to impact life expectancy. It has recently been shown to <a href="https://jamanetwork.com/journals/jamaneurology/article-abstract/2670749?redirect=true" rel="noopener" dir="ltr">increase the risk of Alzheimer’s</a>. According to a recent study from researchers at Boston University, our bodies use the non-REM (rapid eye movement) period of sleep – deep and dreamless – to <a href="https://science.sciencemag.org/content/366/6465/628" rel="noopener" dir="ltr">wash our brain of toxins</a>. By monitoring sleeping patients, scientists were able to show that during non-REM sleep neurons in the brain synchronize, firing on and off together at the same time. When all the neurons are momentarily quiet, they need less oxygen, so less blood flows to the brain. At that point, cerebrospinal fluid – a clear liquid which surrounds the brain – floods into the space left. These waves of fluid help purge the brain of potentially toxic chemical byproducts. This cerebrospinal fluid washing doesn’t occur when we are awake because our neurons are constantly firing and don’t synchronize in the same way.The study also throws up other possibilities, including new potential research avenues for Alzheimer’s treatments. The washing effect of the cerebrospinal fluid could also help clear away molecules associated with the disease. This more general flush-out could have broader benefits than the current drugs being researched, which tend to focus on eliminating the effects of particular molecules.Snoozing isn’t losingProfessor Matthew Walker, a UC Berkeley neuroscientist, argues increasing numbers of us are sleep-deprived and society does not pay enough attention to the problems this creates. As well as authoring a <a href="https://www.ft.com/content/e6ccdcac-133d-11e9-a581-4ff78404524e" rel="noopener" dir="ltr">bestselling book</a> on the subject, he is now a sleep consultant for companies like Google, illustrating how serious and widespread a problem sleeplessness has become.Several large organizations – Google included – have <a href="https://www.ft.com/content/09067126-3720-11e7-99bd-13beb0903fa3" rel="noopener" dir="ltr">sleep pods in their offices</a> to allow employees to take restorative naps.<figure><picture><source type="image/webp" data-srcset="https://assets.weforum.org/editor/responsive_large_webp_73Soo42A7qKVdCI91NoMxNCg77JmngGWUXH_3ujv8LA.webp 850w, https://assets.weforum.org/editor/responsive_medium_webp_oVGjzkKe7gkqJWpsCDR7MOvQgF04a_H440WDsanvLnY.webp 640w, https://assets.weforum.org/editor/responsive_small_webp_h_wNpOilOD1DFZZSWxwFQ4RZkpMzCDtwovNYo0R6Gc4.webp 320w" data-sizes="100vw" srcset="https://assets.weforum.org/editor/responsive_large_webp_73Soo42A7qKVdCI91NoMxNCg77JmngGWUXH_3ujv8LA.webp 850w, https://assets.weforum.org/editor/responsive_medium_webp_oVGjzkKe7gkqJWpsCDR7MOvQgF04a_H440WDsanvLnY.webp 640w, https://assets.weforum.org/editor/responsive_small_webp_h_wNpOilOD1DFZZSWxwFQ4RZkpMzCDtwovNYo0R6Gc4.webp 320w"><img alt="Amount of sleep" src="https://assets.weforum.org/editor/HMsSkoK7lBh8-Idpjy0mNxtRP3aRxR4pqaA3QD_X0YU.png"></picture><figcaption dir="auto">Less than 49% of adults across the world said they got enough sleep.
Image: Statista</figcaption></figure>Huffington Post co-founder Arianna Huffington also argues against the <a href="http://ariannahuffington.com/books/the-sleep-revolution-tr/the-sleep-revolution-hc" rel="noopener" dir="ltr">cultural dismissal of sleep</a>. The busy, always-on way we increasingly conduct our lives contributes to a cycle of sleeplessness that is hampering our physical and mental health, and holding us back from achieving, she says.<figure><picture><source type="image/webp" data-srcset="https://assets.weforum.org/editor/responsive_large_webp_ILT3H3ureIzRVdlwEbOLleP-A4_xyFNcqpI0zcmHhm0.webp 850w, https://assets.weforum.org/editor/responsive_medium_webp_9grP8RYFAKMmvU9U0OsNqnrp1FSK-aSZqdyPwrxvbiY.webp 640w, https://assets.weforum.org/editor/responsive_small_webp_xeQd87Do5Wnl4gi-HjezNSlideZVEc0CRx2Vvr3tasg.webp 320w" data-sizes="100vw" srcset="https://assets.weforum.org/editor/responsive_large_webp_ILT3H3ureIzRVdlwEbOLleP-A4_xyFNcqpI0zcmHhm0.webp 850w, https://assets.weforum.org/editor/responsive_medium_webp_9grP8RYFAKMmvU9U0OsNqnrp1FSK-aSZqdyPwrxvbiY.webp 640w, https://assets.weforum.org/editor/responsive_small_webp_xeQd87Do5Wnl4gi-HjezNSlideZVEc0CRx2Vvr3tasg.webp 320w"><img alt="Lifestyle affecting sleep" src="https://assets.weforum.org/editor/qtOX1vgtEUKZdUinoYHQcKd8r0988jy-0NqtqdWlF_c.png"></picture><figcaption dir="auto">54% of adults said stress was affecting their sleep.
Image: Statista</figcaption></figure>The US Centers for Disease Control and Prevention has declared insufficient sleep a public health problem, with a third of Americans <a href="https://www.sleepdr.com/the-sleep-blog/cdc-declares-sleep-disorders-a-public-health-epidemic/" rel="noopener" dir="ltr">saying they slept</a> for less than six hours a night.A 2017 study which attempted to quantify the economic impact of our sleepless society found a worker sleeping less than six hours a night <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5627640/" rel="noopener" dir="ltr">loses around six working days</a> a year to absenteeism or presenteeism when compared with a worker getting seven to nine hours a night. Other studies suggest developed countries lose about <a href="https://www.rand.org/randeurope/research/projects/the-value-of-the-sleep-economy.html" rel="noopener" dir="ltr">2% of GDP</a> through lack of sleep.<div>Share</div><div>License and Republishing</div>

Scientists are showing how deep sleep wards off illness, opening new research avenues for dementia treatments.

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<ul><li>More people suffer from a lack of sleep, with potential harmful results </li><li>Deep, dreamless sleep clears away brain toxins, scientists believe </li><li>Lack of sleep inflicts big costs on the economy </li> </ul>

From technology entrepreneur <a href="https://www.standard.co.uk/lifestyle/health/11-successful-people-who-get-by-on-hardly-any-sleep-a3598856.html">Elon Musk </a>to former Yahoo! <a href="https://www.forbes.com/sites/alicegwalton/2015/11/13/the-sleep-habits-of-highly-successful-people-infographic/#23300e436d7f">CEO Marissa Mayer </a>and business mogul <a href="https://www.forbes.com/sites/alicegwalton/2015/11/13/the-sleep-habits-of-highly-successful-people-infographic/#23300e436d7f">Richard Branson </a>, there is no shortage of successful people claiming to need just a few hours’ sleep each night.

But while many of them wear their sleeplessness like a badge of pride, scientists woke up to the power of a good night’s sleep some years back. And now they have worked out just how the brain works its magic.

The brain-washing machine

Lack of sleep has been linked to a host of health issues including <a href="https://www.nhs.uk/live-well/sleep-and-tiredness/why-lack-of-sleep-is-bad-for-your-health/">diabetes, depression and heart disease </a>, and is known to impact life expectancy. It has recently been shown to <a href="https://jamanetwork.com/journals/jamaneurology/article-abstract/2670749?redirect=true">increase the risk of Alzheimer’s </a>.

According to a recent study from researchers at Boston University, our bodies use the non-REM (rapid eye movement) period of sleep – deep and dreamless – to <a href="https://science.sciencemag.org/content/366/6465/628">wash our brain of toxins </a>. By monitoring sleeping patients, scientists were able to show that during non-REM sleep neurons in the brain synchronize, firing on and off together at the same time.

When all the neurons are momentarily quiet, they need less oxygen, so less blood flows to the brain. At that point, cerebrospinal fluid – a clear liquid which surrounds the brain – floods into the space left. These waves of fluid help purge the brain of potentially toxic chemical byproducts.

This cerebrospinal fluid washing doesn’t occur when we are awake because our neurons are constantly firing and don’t synchronize in the same way.

The study also throws up other possibilities, including new potential research avenues for Alzheimer’s treatments. The washing effect of the cerebrospinal fluid could also help clear away molecules associated with the disease. This more general flush-out could have broader benefits than the current drugs being researched, which tend to focus on eliminating the effects of particular molecules.

Professor Matthew Walker, a UC Berkeley neuroscientist, argues increasing numbers of us are sleep-deprived and society does not pay enough attention to the problems this creates.

As well as authoring a <a href="https://www.ft.com/content/e6ccdcac-133d-11e9-a581-4ff78404524e">bestselling book </a>on the subject, he is now a sleep consultant for companies like Google, illustrating how serious and widespread a problem sleeplessness has become.

Several large organizations – Google included – have <a href="https://www.ft.com/content/09067126-3720-11e7-99bd-13beb0903fa3">sleep pods in their offices </a>to allow employees to take restorative naps.

Huffington Post co-founder Arianna Huffington also argues against the <a href="http://ariannahuffington.com/books/the-sleep-revolution-tr/the-sleep-revolution-hc">cultural dismissal of sleep </a>. The busy, always-on way we increasingly conduct our lives contributes to a cycle of sleeplessness that is hampering our physical and mental health, and holding us back from achieving, she says.

The US Centers for Disease Control and Prevention has declared insufficient sleep a public health problem, with a third of Americans <a href="https://www.sleepdr.com/the-sleep-blog/cdc-declares-sleep-disorders-a-public-health-epidemic/">saying they slept </a>for less than six hours a night.

A 2017 study which attempted to quantify the economic impact of our sleepless society found a worker sleeping less than six hours a night <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5627640/">loses around six working days </a>a year to absenteeism or presenteeism when compared with a worker getting seven to nine hours a night. Other studies suggest developed countries lose about <a href="https://www.rand.org/randeurope/research/projects/the-value-of-the-sleep-economy.html">2% of GDP </a>through lack of sleep.

Want to have a healthy brain? Make sure you're washing it every day

The lack of sleep

Sleep washes the brain

Lack of sleep affects the economy

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