National Geographic

a million auto accidents each year, as well as to asignificant number of medical errors. Even smalladjustments in sleep can be problematic. TheMonday after a daylight saving time change inthe U.S., there’s a 24 percent increase in heartattacks, compared with other Mondays, and ajump in fatal car crashes too.During our lifetimes, about a third of us willsufer from at least one diagnosable sleep disor-der. They range from chronic insomnia to sleepapnea to restless leg syndrome to much rarerand stranger conditions.In exploding head syndrome, booming soundsseem to reverberate in your brain as you try tosleep. A Harvard study found that sleep paral-ysis—the inability to move for a few minutesafter you’ve woken from dreaming—is the gen-esis of many alien abduction stories. Narcolep-tic attacks, uncontrollable episodes of suddensleep onset, often are triggered by strongly pos-itive emotions, such as listening to a joke, beingtickled, or tasting delicious food. People withKleine-Levin syndrome will, every few years,sleep nearly nonstop for a week or two. Theyreturn to regular cycles of consciousness with-out any discernible side efects.Insomnia is by far the most common prob-lem, the main reason 4 percent of U.S. adultstake sleeping pills in any given month. Insomni-acs generally take longer to fall asleep, wake upfor prolonged periods during the night, or both.If sleep is such a ubiquitous natural phenome-non, refined across the eons, you might wonder,why do so many of us have such trouble with it?Blame evolution; blame the modern world. Orblame the mismatch between the two.Evolution endowed us, like other creatures,with sleep that is malleable in its timing andreadily interruptible, so it can be subordinatedto higher priorities. The brain has an overridesystem, operating in all stages of sleep, that canrouse us when it perceives an emergency—thecry of a child, say, or the footfall of an approach-ing predator.The problem is that in the modern world,our ancient, innate wake-up call is constantlytriggered by non–life-threatening situations,like anxiety before an exam, worries aboutfinances, or every car alarm in the neighbor-hood. Before the industrial revolution, whichbrought us alarm clocks and fixed work sched-ules, we could often counteract insomnia sim-ply by sleeping in. No longer. And if you’re one5%of women``````3%of men``````Canada$21.4 1.35%``````United States2.28%``````United Kingdom$50.2 1.86%``````Germany$60 1.56%``````Japan$138.6 2.92%2016 202117.8$27.5 billion9.411.97.2 9.0‘16 ‘21 ‘16 ‘21Sleep apneadevices``````Medications Sleepcenters``````BY AGE20-39 1.8%40-49 4.950-59 6.060-69 5.570-79 5.7+80 7.0$411 billion+9.1% +4.8% +4.6%Billion $/year % GDP lost0THE AGE OF SLEEP AIDSTHE MARKET FOR SLEEPTHE COST OF SLEEPLESSNESSA Centers for Disease Control and Preventionstudy found that older Americans are more likelyto use prescription sleep aids than their youngercounterparts. Women were also slightly morelikely than men to report they used sleep aids.``````Sleep-deprived consumers paid $66 billion in2016 for devices, medications, and sleep studies.The figure could rise to $85 billion by 2021.``````A 2017 Rand study found that lack of sleep canresult in reduced productivity as well as morework absences, industrial and road accidents,health care expenses, and medical errors.``````NGM STAFF. SOURCES: U.S. CENTERS FOR DISEASE CONTROLAND PREVENTION; BCC RESEARCH; RAND EUROPESLEEP 67