I’ve been kept up at night by Matthew Walker’s absolutely riveting Why We Sleep. Walker, a Professor of Neuroscience and Psychology at the University of California, Berkeley and Director of the Sleep and Neuroimaging Laboratory, shares with us his ground-breaking research into sleep in this accessible and entertaining book. And the good news is, I’ll never feel guilty going to bed early ever again!

Over the past 20 years, our understanding of sleep has leapfrogged. Sleep, it turns out, is essential for our mental health, memory, learning, creativity, decision making, immune system, blood pressure, preventing dementia and depression, and maintaining a healthy body weight. The list goes on and on.

Walker explains what actually happens in your brain as you doze off and the different kinds of sleeps, NREM and REM. Did you know that during REM sleep, or dream sleep, your entire body except your eyeballs is paralysed? Otherwise, you would ‘act’ out your dreams. Or that sleep-walking and sleep-talking has nothing to do with your dreams? He goes into insomnia, the deathly effect of continuous sleep deprivation, the effects of alcohol on sleep, what actually happens when you sleep-walk or sleep-talk. He demonstrates links between car crashes and lack of sleep. And it’s all done in easily grasped layman’s language and excellently conceived analogies.

Surprising and entertaining facts abound in this book. Did you know, for example, that the reason some fish are able to swim while they sleep is because only half their brain sleeps at a time? Or that birds, which also sleep with half a brain at a time, keep the eye on the alert side of the brain open to look out for danger? Even more incredibly, to allow for a ‘full brain’ slumber, flocks of birds line up in a row with half-brain sleeping ‘guard’ birds at each end of the row facing the opposite direction, thereby keeping an eye out for dangers on both sides. Nerdy stuff, I know, but quite fun nonetheless.

Somehow, sleep in our culture is associated with laziness. High achievers often advertise the fact that they don’t ‘need’ much sleep and we assume it’s part of the explanation for their success. Famously, both Ronald Reagan and Margaret Thatcher got by with four hours of a night. Walker can’t help but speculate what role that played in their development of dementia. More frighteningly, Donald Trump claims to sleep 3-4 hours a night, when you know how sleep deprivation effects decision making, it doesn’t look pretty.

I’ll leave you with a quote from the book by American entrepreneur E. Joseph Cossman which rings true for me, at least:

The best bridge between despair and hope is a good night’s sleep.

Why We Sleep is published by Penguin, 342 pages.