Chronic insomnia is linked to a multitude of physical and psychological ills: increased risk of cancer, hypertension, heart disease, obesity, diabetes, infertility, miscarriage, depression, anxiety, irritability, dementia, impaired cognitive and reasoning skills, lowered immune-system function, heightened awareness of pain, and who knows what else? Probably bunions, dandruff, and pinkeye. But while insomnia apparently contributes to, results from, or is comorbid with the ailments on this laundry list, why we get insomnia, which parts of the brain are most implicated, and how it actually hurts us, even what it is exactly, all remain largely a mystery, as does sleep itself. Thus researchers summed up a lengthy 2005 National Institutes of Health report on insomnia with deadpan succinctness: "Little is known about the mechanisms, causes, clinical course, co-morbidities, and consequences of chronic insomnia."
What's undisputed, however, is that sleep is as necessary to physical and mental health as air and water, and that, without it, we suffer—often severely. So, those annoying world-beaters, who brag about needing only four hours of sleep a night (the better to forge multimillion-dollar start-ups and do their Nobel Prize–winning research) are perhaps not being entirely candid. According to sleep expert Thomas Roth of the Henry Ford Sleep Disorders Center in Detroit, "The percentage of the population who need less than five hours of sleep per night, rounded to a whole number, is zero."
Yet if a vast conspiracy were afoot to create an entire civilization of insomniacs, it would operate pretty much the way our society does now. Over the past century or so—roughly coresponding with the invention and worldwide adoption of electricity—the average time allotted to sleep in the industrialized world has shrunk by as many as four or five hours. The average North American now sleeps about six and a half hours a night—even fewer for ambitious careerists on an upward trajectory—down from eight hours a generation ago and ten hours in the early 20th century. In fact, thanks to technology, particularly the Internet, there's nothing you can do during the day that you can't do at night. The glory of 24/7 is that, using our computers or TVs or cell phones, we can continue working, buying, selling, playing, communicating, gambling, managing our portfolios, following the latest news in Karachi, or London, or Santiago, or Shanghai without stopping for a time-waster like sleep.
And we have a consumer industry to aid us in these pursuits. In all but the most godforsaken wilderness, it's possible to get in your car and find an all-night gas station that sells submarine sandwiches and any number of high-jolt, caffeine- and sugar-infused canned beverages with names like "Spike," "Fuel Cell," "Wired," and "Powershot." Here in the United States, where we work longer hours and take fewer vacations than citizens of any other Western nation, sleeping more than is absolutely necessary seems to be regarded as a form of sloth: you aren't really serious about your career unless you show up for work at 6:00 a.m. with bags under your eyes and don't leave until 9:00 p.m.