Imagine if there was a medicine you could take that was guaranteed to make you live longer. A medicine that could help you stay slim, protect you from infection and keep you feeling happy and fulfilled. Interested? Well, listen to this: the medicine in question not only exists, it is already available free of charge in your own home. It's called sleep.
In his new book Why We Sleep, Matthew Walker – a professor of neuroscience and psychology and director of the University of California, Berkeley’s Center for Human Sleep Science – catalogues the benefits of this undervalued miracle cure. He is convinced that we are in the grip of a « catastrophic sleep-loss epidemic », whose true costs are astronomical. « No aspect of our biology is left unscathed by sleep deprivation, » Walker told Britain’s Observer newspaper, « and yet no one is doing anything about it. Sleep loss costs the UK economy over £30 billion a year in lost revenue, or 2% of GDP. »
In his book, Walker charts the drastic changes in sleeping habits that have taken place over the past 75 years. In 1942, less than 8% of the population was making do with six hours sleep or less each night. Today, the figure has risen to almost 50%. And the consequences are disturbing, to say the least. Walker cites large-scale scientific studies to demonstrate that the shorter your sleep, the shorter your life.
« After just one night of only four or five hours’ sleep, your natural killer cells – the ones that attack the cancer cells that appear in your body every day – drop by 70%, » Walker told the Observer. Adults aged over 45 who sleep less than six hours a night are three times more likely to have a heart attack or stroke than those who sleep for seven or eight hours. Short sleep makes you more susceptible to weight gain, while getting too little sleep throughout your adult life significantly raises your risk of developing Alzheimer’s disease.
Walker’s book is a powerful argument for making a concerted effort to get to bed earlier. « I take my sleep incredibly seriously, because I have seen the evidence, » he said. He keeps regular hours and won’t settle for less than eight hours sleep every night. Maybe you should be doing the same.
Why We Sleep: The New Science of Sleep and Dreams is published by Allen Lane in the UK and by Scribner in the USA