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<\/p>\nOn a typical workday morning, if you\u2019re like\u00a0most people<\/a>, you don\u2019t wake up naturally. Instead, the ring of an alarm clock probably jerks you out of sleep. Depending on when you went to bed, what day of the week it is, and how deeply you were sleeping, you may not understand where you are, or why there\u2019s an infernal chiming sound. Then you throw out your arm and hit the snooze button, silencing the noise for at least a few moments. Just another couple of minutes, you think. Then maybe a few minutes more.<\/p>\n It may seem like you\u2019re giving yourself a few extra minutes to collect your thoughts. But what you\u2019re actually doing is making the wake-up process more difficult and drawn out. If you manage to drift off again, you are\u00a0likely plunging<\/a>\u00a0your brain back into the beginning of the sleep cycle, which is the worst point to be woken up\u2014and the\u00a0harder we feel<\/a>\u00a0it is for us to wake up, the worse we think we\u2019ve slept. (Ian Parker wrote about\u00a0the development of a new drug for insomnia<\/a>\u00a0in the magazine last week.)<\/p>\n One of the consequences of waking up suddenly, and too early, is a phenomenon called sleep inertia. First\u00a0given a name<\/a>\u00a0in 1976, sleep inertia refers to that period between waking and being fully awake when you feel groggy. The more abruptly you are awakened, the more severe the sleep inertia. While we may feel that we wake up quickly enough, transitioning easily between sleep mode and awake mode, the process is in reality far more\u00a0gradual<\/a>. Our brain-stem arousal systems (the parts of the brain responsible for basic physiological functioning) are activated almost instantly. But our cortical regions, especially the prefrontal cortex (the part of the brain involved in decision-making and self-control), take longer to come on board.<\/p>\n In those early waking minutes, our\u00a0memory<\/a>,\u00a0reaction time<\/a>,\u00a0ability to perform<\/a>\u00a0basic mathematical tasks, and\u00a0alertness and attention<\/a>\u00a0all suffer. Even simple tasks, like finding and turning on the light switch, become far more complicated. As a result, our decisions are neither rational nor optimal. In fact, according to Kenneth Wright, a neuroscientist and chronobiology expert, \u201cCognition is best several hours prior to habitual sleep time, and worst near habitual wake time.\u201d In the grip of sleep inertia, we may well do something we know we shouldn\u2019t. Whether or not to hit the snooze button is just about the first decision we make. Little wonder that it\u2019s not always the optimal one.<\/p>\n Other research has found that sleep inertia can last two hours or longer. In\u00a0one study<\/a>\u00a0that monitored people for three days in a row, the sleep researchers Charles Czeisler and Megan Jewett and their colleagues at Harvard Medical School found that sleep inertia took anywhere from two to four hours to disappear completely. While the participants said they\u00a0felt<\/i>\u00a0awake after two-thirds of an hour, their cognitive faculties didn\u2019t entirely catch up for several hours. Eating breakfast, showering, or turning on all the lights for maximum morning brightness didn\u2019t mitigate the results. No matter what, our brains take far longer than we might expect to get up to speed.<\/p>\n When we do wake up naturally, as on a relaxed weekend morning, we do so based mainly on two factors: the amount of external light and the setting of our internal alarm clock\u2014our circadian rhythm. The internal clock isn\u2019t perfectly correlated with the external one, and so every day, we use outside time cues, called zeitgebers, to make fine adjustments that mimic the changes in light and dark that take place throughout the year.<\/p>\n The difference between one\u2019s actual, socially mandated wake-up time and one\u2019s natural, biologically optimal wake-up time is something that Till Roenneberg, a professor of chronobiology at Ludwig-Maximilians University in Munich, calls \u201csocial jetlag.\u201d It\u2019s a measurement not of sleep duration but of sleep timing: Are we sleeping in the windows of time that are best for our bodies? According to Roenneberg\u2019s\u00a0most recent estimates<\/a>, based on a database of more than sixty-five thousand people, approximately a third of the population suffers from extreme social jetlag\u2014an average difference of over two hours between their natural waking time and their socially obligated one. Sixty-nine per cent suffer from a milder form, of at least one hour.<\/p>\n Roenneberg and the psychologist Marc Wittmann have\u00a0found<\/a>\u00a0that the chronic mismatch between biological and social sleep time comes at a high cost: alcohol, cigarette, and caffeine use increase\u2014and each hour of social jetlag\u00a0correlates<\/a>\u00a0with a roughly thirty-three per cent greater chance of obesity. \u201cThe practice of going to sleep and waking up at \u2018unnatural\u2019 times,\u201d Roenneberg\u00a0says<\/a>, \u201ccould be the most prevalent high-risk behaviour in modern society.\u201d According to Roenneberg, poor sleep timing stresses our system so much that it is one of the reasons that night-shift workers often suffer higher-than-normal rates of\u00a0cancer<\/a>,\u00a0potentially fatal heart conditions<\/a>, andother<\/a>\u00a0chronic disease, like\u00a0metabolic syndrome and diabetes<\/a>.\u00a0Another study<\/a>, published earlier this year and focussing on medical-school performance, found that sleep timing, more than length or quality, affected how well students performed in class and on their preclinical board exams. It didn\u2019t really matter how long they had slept or whether they saw themselves as morning people or not; what made a difference was when they actually went to bed\u2014and when they woke up. It\u2019s bad to sleep too little; it\u2019s also bad, and maybe even worse, to wake up when it\u2019s dark.<\/p>\n Fortunately, the effects of sleep inertia and social jetlag seem to be reversible. When Wrightasked<\/a>\u00a0a group of young adults to embark on a weeklong camping trip, he discovered a striking pattern: before the week was out, the negative sleep patterns that he\u2019d previously observed disappeared. In the days leading up to the trip, he had noted that the subjects\u2019 bodies would begin releasing the sleep hormone melatonin about two hours prior to sleep, around 10:30\u00a0P.M.<\/small>A decrease in the hormone, on the other hand, took place after wake-up, around\u00a08 A.M.<\/small>\u00a0After the camping trip, those patterns had changed significantly. Now the melatonin levels increased around sunset\u2014and decreased just after sunrise, an average of fifty minutes before wake-up time. In other words, not only did the time outside, in the absence of artificial light and alarm clocks, make it easier for people to fall asleep, it made it easier for them to wake up: the subjects\u2019 sleep rhythms would start preparing for wake-up just after sunrise, so that by the time they got up, they were far more awake than they would have otherwise been. The sleep inertia was largely gone.<\/p>\n Wright concluded that much of our early morning grogginess is a result of displaced melatonin\u2014of the fact that, under current social-jetlag conditions, the hormone typically dissipates two hours after waking, as opposed to while we\u2019re still asleep. If we could just synchronize our sleep more closely with natural light patterns, it would become far easier to wake up. It wouldn\u2019t be unprecedented. In the early nineteenth century, the United States had a hundred and forty-four separate time zones. Cities set their own local time, typically so that noon would correspond to the moment the sun reached its apex in the sky; when it was noon in Manhattan, it was five till in Philadelphia. But on November 18, 1883, the country settled on four standard time zones; railroads and interstate commerce had made the prior arrangement impractical. By 1884, the entire globe would be divided into twenty-four time zones. Reverting to hyperlocal time zones might seem like it could lead to a terrible loss of productivity. But who knows what could happen if people started work without a two-hour lag, during which their cognitive abilities are only shadows of their full selves?<\/p>\n Theodore Roethke had the right idea when he wrote his famous line \u201cI wake to sleep, and take my waking slow.\u201d We do wake to a sleep of sorts: a state of not-quite-alertness, more akin to a sleepwalker\u2019s unconscious autopilot than the vigilance and care we\u2019d most like to associate with our own thinking. And taking our waking slow, without the jar of an alarm and with the rhythms of light and biology, may be our best defense against the thoughtlessness of a sleep-addled brain, a way to insure that, when we do wake fully, we are making the most of what our minds have to offer.<\/p>\n Maria Konnikova<\/a>\u00a0is the author of \u201cMastermind: How to Think Like Sherlock Holmes<\/a>.\u201d<\/em><\/p>\n Photograph: Keystone-France\/Gamma-Keystone\/Getty<\/em>.<\/p>\n<\/div>\n<\/article>\n<\/div>\n","protected":false},"excerpt":{"rendered":" Zeitgerbers: Outside time cues that make fine adjustments which mimic the changes in light and dark that take place throughout the year. http:\/\/www.newyorker.com\/online\/blogs\/elements\/2013\/12\/science-of-sleep-trouble-with-snooze-buttons.html DECEMBER 10, 2013 SNOOZERS ARE, IN FACT, LOSERS POSTED BY\u00a0MARIA KONNIKOVA On a typical workday morning, if you\u2019re like\u00a0most people, you don\u2019t wake up naturally. Instead, the ring of an alarm clock … Continue reading Zeitgebers<\/span>