Get some sleep. That’s the urgent advice the newly refreshed science of slumber has for North Americans.
Never mind the majority who got less than the recommended eight hours of sleep last night. In April, yet another air-traffic controller – the fifth in as many months – was suspended for falling asleep on the job, leaving a plane circling Reno, Nev., for 16 minutes with no one in the control tower to talk to.
A more alert tin-pusher on duty in neighbouring California eventually talked down the pilot – who, unlike several infamous colleagues last year, was awake. A British pilots-union survey recently discovered that 20 per cent of pilots pass out on the job.
We live under the enduring spell of The Warrior Who Does Not Sleep, believing that many accomplished people survive on no more than 4.5 hours of “core sleep” a night. It’s a myth.
Many heroic non-sleepers used pills (John F. Kennedy was a walking pharmacy and once fell asleep interviewing a prospective secretary of agriculture) or were inveterate nappers (Napoleon, Ronald Reagan, Bill Clinton and even Winston Churchill, who used sleeping tablets and survived his famous midnight meetings by climbing into bed for an hour every single afternoon).
And as David Dinges, chief of the division of sleep and chronobiology at the University of Pennsylvania School of Medicine, points out: “There are lots of other heroic, high-achieving figures – Einstein, Albert Schweitzer – who got their sleep.”
But we want to believe we’re big kids who don’t need to go to bed.
Our stubborn refusal is making the world a measurably more dangerous place. Sleep scientists make few exceptions – most of us need 7½ hours in bed, and preferably eight, to be fully capable. Top performers (such as violinists) often need more than eight, plus an afternoon nap.
Human sleep is regulated by a circadian clock located in a tiny, cone-shaped but essential intersection of cells in the hypothalamus called the suprachiasmatic nucleus. It is in turn fed by ganglion cells in the retina, which take their cues from light and dark cycles – that is, the rising and setting sun, the main determinant of when we want to wake up and when we want to sleep.
The farther we stray from that simple schedule, the more we pay.
In a 2007 study, U.S. Army researchers found that two sleepless nights impaired the prefrontal cortex’s ability to integrate cognitive and emotional processes, which in turn interfered with the ability to make moral judgments. Sleeplessness, in other words, makes the mind one-dimensional, which is why it was used at Abu Ghraib. Sleep deprivation as a torture dates at least as far back as medieval Italy, when Ippolito Marsili invented the so-called alarm clock: The victim could avoid anal penetration if he stayed awake. (If you work in a modern corporation, this may sound familiar.) We need one hour of sleep for every two we stay alert.
Because sleep is when the body and especially the brain regenerate and repair themselves, sleeplessness has been identified as a factor in an endless list of afflictions, including hypertension, heart disease, diabetes, obesity, memory loss, bipolar disorder, reduced immunity, mood swings, impaired carbohydrate metabolism and increased heart-rate variability. Not to mention depression and substance abuse and the impairment of memory, self-expression and the ability to read emotions in others. Oh, and a hundred thousand motor-vehicle accidents a year
A hamster kept awake for three days will die. Randy Gardner, a high-school student, stayed awake for a record of just over 11 days as part of a 1964 Stanford University study. By the end, he couldn’t talk. Former prime minister Kim Campbell blamed the implosion of the Conservative Party under her leadership on sleep deprivation. Yasser Arafat slept only three to five hours a day – yet another model human being. We stay awake at our peril.
Going, going, yawn