IN THE screen-lit bustle of modern life, sleep is expendable. There are television shows to binge-watch, work emails to answer, homework to finish, social media posts to scroll through. We’ll catch up on shut-eye later, so the thinking goes – right after we click down one last digital rabbit hole.
Brain research, which has pushed back hard against this nonchalant attitude, is now expanding rapidly, reaching beyond the laboratory and delving into exactly how sleep works in disease and in normal cognitive functions such as memory. The growing consensus is that casual disregard for sleep is wrongheaded – even downright dangerous.
Preschoolers who skip naps are worse at a memory game than those who snooze, even after the children “catch up” on sleep the next night. An alarming new line of research suggests poor sleep may increase the risk of Alzheimer’s, as even a single night of sleep deprivation boosts brain levels of the proteins that form toxic clumps in Alzheimer’s patients. All-nighters push anxiety to clinical levels, and even modest sleep reductions are linked to increased feelings of social isolation and loneliness.
“It used to be popular for people to say, ‘I’ll sleep when I’m dead’. The ironic thing is, not sleeping enough may get you there sooner,” said Daniel Buysse, a professor of sleep medicine at the University of Pittsburgh.
The research is changing policy in some areas, with school officials, for example, considering whether to push back school start times to better match teenagers’ sleep cycles. The National Sleep Foundation will hold its first consumer expo in March, with offerings ranging from mattresses to sleep trackers – a visible sign of the burgeoning sleep industry. Meanwhile, a growing number of scientists, not normally known for being advocates, are bringing evangelical zeal to the message that lack of sleep is an escalating public health crisis that deserves as much attention as the obesity epidemic.
“We’re competing against moneyed interests, with technology and gaming and all that. It’s so addictive and so hard to compete with,” said Orfeu Buxton, a sleep researcher at Pennsylvania State University. “We’ve had this natural experiment with the Internet that swamped everything else.”
The sleep research community, formerly balkanised into separate sleep disorders such as insomnia and sleep apnea, has begun to coalesce around the concept of “sleep health” – which for most adults means getting at least seven hours a night. But time in the sack has been steadily decreasing.
In 1942, a Gallup poll found that adults slept an average of 7.9 hours per night. In 2013, the average adult had sheared more than an hour off that number. In 2016, the Centers for Disease Control and Prevention reported that a third of adults fail to get the recommended seven hours.
In the blink of an eye, in evolutionary terms, humans have radically altered a fundamental biological necessity – with repercussions we are still only beginning to understand.
“When you are asleep, it’s the most idiotic of all things: You’re not finding food, not finding a mate. Worse still, you’re vulnerable to predation,” said Matthew Walker, a psychology professor at the University of California at Berkeley. “If there was a chance to shave even 10 per cent to 20 per cent of that time, Mother Nature would have weeded it out through the process of evolution millions of years ago.”
For most of human history, scientific understanding of sleep was limited to asking people how they felt afterward. The discovery in the early 1950s of rapid-eye-movement sleep, when the brain crackled with electrical activity and dreams, changed the field forever. Electroencephalography (EEG) research revealed the sleeping mind cycles through active stages of light and deeper sleep that repeat about every 90 minutes.
For years, animal studies have shown that learning activities are reactivated during sleep, a critical part of how lasting memories are formed. More recently, Princeton postdoctoral researcher Monika Schönauer asked 32 people to sleep in the lab after they had been asked to memorise 100 pictures of houses or faces. By analysing their patterns of electrical brain activity, she found she could effectively read their minds, predicting which images they had been studying while awake – because they were replaying them. – Text and Photo by The Washington Post