You know shut-eye is good for you—but when 11 p.m. comes around, it’s so tempting to keep scrolling through Instagram. Sure, I could use more rest, you think. Then again, who couldn’t? Early bedtimes are for second graders. All right, then. If you believe you’re a hardy soul who functions perfectly well on six hours a night (five if there’s a House Hunters marathon), try this: Sit in a quiet, dark room with a pencil in your hand. Set a timer for five minutes and relax.

Dropped the pencil? You may have just nodded off. When sleep pressure (the official term for our urge to sleep) builds up, says Hans Van Dongen, PhD, director of the Sleep and Performance Research Center at Washington State University, the brain will grab any opportunity for a micro catnap—even just half a second. Sleep is stealthy that way. In one study, people who slept only six hours or less a night for two weeks scored as poorly on tests of their attention, memory, and reaction times as those who’d been up for two nights straight.

About one in three Americans gets fewer than seven hours of sleep nightly, according to the CDC, which has called insufficient sleep a public health problem that leaves us vulnerable to car crashes, medical errors, and industrial accidents, along with a host of chronic diseases. Research also shows that sleep deprivation costs the U.S. economy up to $411 billion in lost productivity each year, makes us crankier, and gives us crow’s-feet.

Think about all this the next time you go for your third espresso or doze off during the sales meeting. Would you say no to a magic elixir that can make you healthier, safer, smarter, prettier, nicer, happier— at no cost? We thought not. So curl up and settle in for a different kind of bedtime story.

Photo: David Arky

Emotional Rescue
Do you need a shrink—or a good night's sleep?

Your husband snipes that you forgot to pay the Visa bill again, and the sobs start to build in your throat. Does he think you’re an idiot? Everything’s gone wrong today! On top of that, you’ve tossed and turned three nights in a row, and now your eyeballs feel as if they’ve been rolled in sand. You fear you may be losing your grip. What is going on?

When we’re tired, we feel less equipped to handle life—because we are less equipped to handle life. Getting too little sleep can affect our powers of emotional control and regulation, as well as our ability to think a few steps ahead. These higher-level functions, managed by an area of the brain called the prefrontal cortex, begin to shut down when we’re insufficiently rested. And according to William Killgore, PhD, professor of psychiatry, psychology, and medical imaging at the University of Arizona, just one off night can compromise your ability to “tap the brakes on the emotional centers of your brain.” That leaves you prone to overreacting in situations bad or good. You’re more inclined to feel frustrated, hurt, and oversensitive, or you may feel anxious and out of it. Meanwhile, up goes the volume on your amygdala, the threat-responsive part of the brain. In a study last year, Killgore and his colleagues looked at the effect pulling an all-nighter has on one’s ability to detect emotions via facial expressions. The research, published in the journal Neurobiology of Sleep and Circadian Rhythms, found that sleep-deficient subjects had a tough time identifying happy and sad faces but could still process “survival” emotions like fear, anger, or disgust. That’s why when you’re tired, every interaction may seem a little worse—your brain is focused on who might be out to get you.

And yes, all of this can chip away at your happiness the next day and lead to mood disorders long-term. “In our studies, two nights of no sleep significantly increases symptoms of depression and paranoia, as well as anxiety levels,” says Killgore. So lights-out, and see if you wake up a newer, saner, brighter person.

A Sobering Thought
There's a reason we say tired people are "punch-drunk."

Pop quiz: Worker fatigue is believed to have contributed to which of the following catastrophes?

  • A. The crash of the Exxon Valdez
  • B. The nuclear reactor meltdown at Three Mile Island
  • C. The explosion of the space shuttle Challenger
  • D. All of the above

    D. Exhausted people are slower to react and less aware of their surroundings, and they operate with impaired judgment—just as one does after having too much to drink. You may not be the head of mission control, but drowsy driving can be as dangerous as getting behind the wheel after ti many martoonis. Consider the numbers:
  • Going without sleep...from 6 a.m. to midnight (18 hours) can be like drinking* two glasses of wine in one hour (a blood alcohol level of 0.05 percent).
  • Going without sleep...for an entire night can be like drinking* four glasses of wine in two hours (a blood alcohol level of 0.10 percent).
    *For a 140-pound woman

    Photo: David Arky

    This is your body on not-enough rest.

    The longer you’re awake, the more a chemical called adenosine builds up, making you feel increasingly drowsy. If you don’t snooze, your brain will become less active, causing lapses in attention and focus.

    The Brain's Cortex
    When you sleep, your brain clears out waste products like beta-amyloid proteins; get too little, and they start to increase—and may eventually clump together to form the hallmark plaques of Alzheimer’s. Chronic sleep problems may also lead to tau protein tangles, another telltale sign of dementia.

    The more hours your eyes are open, the more likely you’ll suffer from dryness the next day.

    Healthy adults who sleep five or fewer hours per night are 50 percent more likely to have stiffer blood vessels and arterial plaque buildup than people who get seven hours; those changes can increase their risk of cardiovascular disease.

    Compared to the well-rested, sleep-deprived folks can appear to have droopier eyelids, swollen eyes, darker under-eye circles, paler skin, and downturned corners of the mouth, one study found, and are more likely to think of themselves as less attractive, less healthy, and sad.

    Too little sleep can lead the brain to release hormones that impair muscle growth, inhibiting recovery after exercise or injury.

    Not only does not getting enough good sleep potentially raise the risk for breast cancer, but sleep-deprived postmenopausal women are more likely to be diagnosed with aggressive later-stage tumors, one study found.

    G.I. System
    Prolonged disrupted sleep causes immune cells to secrete inflammatory substances that can exacerbate G.I. issues such as Crohn’s disease and ulcerative colitis. (Digestive conditions can also keep you up at night.)

    For every hour under seven by which you cut your nightly sleep, you increase your likelihood of developing type 2 diabetes by 9 percent (sleeping over nine hours also boosts risk). As many as 10 to 40 percent of people with this metabolic condition develop kidney failure.

    People who sleep fewer than six hours a night have a nearly 50 percent greater risk for benign tumors that are, in most cases, a precursor to colon cancer than those who log at least seven hours.

    Immune System
    When researchers measured healthy people’s sleep, then exposed them to a cold virus, those who got fewer than six hours a night were more than four times as likely to sniffle and sneeze than those who regularly slept seven hours or more.

    Sleep loss is associated with weight gain and obesity. One possible reason: Higher-than-normal levels of appetite-raising chemicals in sleep-deprived people may make them likely to snack too much in the afternoon.

    Getting fewer than five hours a night can result in fine lines, sagging, loss of plumpness, and dark spots. Skimping on sleep can also exacerbate disorders such as eczema and psoriasis, possibly because it increases inflammation, triggering flare- ups. Nighttime itchiness from these disorders can disrupt sleep, only compounding the problem.

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