8 horrible things that happen if you don't get enough sleep

Whether it's because we're staying up to squeeze in a final episode of "The OA" or scrolling through Facebook, nearly 40% of us get less than seven hours of sleep a night, according to a recent Gallup poll. And the CDC estimates that another 50-70 million Americans likely have a sleep disorder.

Here are eight horrible things that can happen if you don't get enough sleep:

Colds

If you're wondering why you're sick all the time and seem to pick up every bug that travels around the office, it's probably because you're not getting enough sleep. When a group of 153 people were exposed to a common cold, those who had gotten less than 7 hours of sleep in the two weeks prior were almost 3 times more likely to get sick than those who'd had 8 or more hours of sleep. How well you sleep is also a factor — those who had spent 92% of their time in bed actually asleep were 5.5 times more likely to catch a cold than those who had been peacefully slumbering 98-100% of the time they were in bed.

Source: Archives of Internal Medicine, 2009

Tummy troubles

250 Americans currently experience. Additionally, people with Crohn's disease were twice as likely to experience a relapse when they weren't getting enough sleep.

Source: World Journal of Gastroenterology, 2013

Irritability and mood swings

Researchers have found that interruptions and disturbances tend to bother us more when we haven’t slept. "Complaints of irritability and [emotional] volatility following sleepless nights" are common, a team of Israeli researchers observed after following a group of underslept medical residents. The study found that the negative emotional effect of disruptive events — things like being interrupted while in the middle of doing something — were amplified by sleep loss.

Source: Sleep, 2005

Headaches and migraines

If you've ever noticed, after a night of tossing and turning, that you're not only irritable at work but also in pain, chances are they could be linked. Researchers still don't know exactly why sleep deprivation appears to cause headaches — but it's a connection doctors have noticed for more than a century. Migraines can be triggered by sleepless nights, and 36 to 58% of people with sleep apnea wake up with "nondescript morning headaches."

Source: Headache, 2003; Headache, 2005

Difficulty learning

Sleep deprivation interferes with our ability to remember and process new information, which is why dozens of scientists have recommended pushing back early work and school start times. In fact, one study of middle school students found that "delaying school start times by one hour, from roughly 7:30 to 8:30, increases standardized test scores by at least 2 percentile points in math and 1 percentile point in reading."

Source: Nature, 1999; Nature Neuroscience, 2000; Education Next, 2012

Depleted sex drive

Sleep deprivation and disturbed sleep have been linked with reduced libido and sexual dysfunction, and people suffering from sleep apnea appear to be at particular risk.

Source: American Journal of Obstetrics and Gynecology, 2007; Behavioral Brain Research, 2009; Journal of Sexual Medicine, 2009; Sleep Medicine, 2010; Brain Research, 2011

Poor vision

Having trouble focusing your eyes on this text? Sleep deprivation is linked with tunnel vision, double vision, and dimness. The longer you’re awake, the more visual errors you'll see and the more likely you are to hallucinate.

Source: International Journal of Occupational Medicine and Environmental Health, 2010

Weight gain

People who are underslept seem to have hormone imbalances that are tied to increased appetite, more cravings for high-calorie foods, a greater response to indulgent treats, and a dampened ability to control their impulses. Sure, you burn more calories when you're awake, but not nearly enough to cancel out the many excess ones you consume when you're exhausted.

Source: Journal of Clinical Endocrinology & Metabolism, 2012; PLOS Medicine, 2004; Nature Communications, 2013; PNAS, 2013

Lauren F. Friedman contributed to an earlier version of this article.

8 horrible things that happen if you don't get enough sleep

Surrounding ourselves with screens comes with an unexpected side effect: We cant sleep. And our bodies and minds are suffering.

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