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

From technology entrepreneur Elon Musk to former Yahoo! CEO Marissa Mayer and business mogul Richard Branson, 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 diabetes, depression and heart disease, and is known to impact life expectancy. It has recently been shown to increase the risk of Alzheimer’s.

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 wash our brain of toxins. 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 losing

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 bestselling book 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 sleep pods in their offices to allow employees to take restorative naps.

Huffington Post co-founder Arianna Huffington also argues against the cultural dismissal of sleep. 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 saying they slept 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 loses around six working days 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 2% of GDP through lack of sleep.