16 Scary Things That Happen to Your Body When You Don’t Get Enough Sleep

When you crawl under the covers and fall asleep at night, your body and brain go to work, essentially running a critical reboot process. Most of the good stuff happens when you’ve reached a deep sleep, which is why it’s so important to get a full night’s rest (which is 7 to 9 hours for most adults).

During this most restorative sleep phase, your blood pressure drops, muscles relax, blood supply to muscles increases, tissue is grown and repaired, energy is restored, and hormones are released. Pretty impressive, right?

But, according to a study from the Centers for Disease Control and Prevention, more than a third of American adults aren’t getting enough shut-eye on a regular basis.

Not sleeping enough can lead to an array of health problems. In honor of National Sleep Awareness Month (March), we want to inspire you to get the sleep your body so desperately needs. Since we know you’re well aware sleep is good for you, but chances are you’re still not getting enough of it, we’re here to scare you straight with the tough facts about exactly what happens to your mind and body when you are sleep-deprived.

1. You’re adding inches to your waistline

Getting enough ZZZs could translate to losing LBs. A 2017 study from the University of Leeds found that people who sleep, on average, 6 hours a night had a waist measurement that was 3 centimeters greater than those who were logging 9 hours a night. Here’s where things get really interesting: The study did not find any correlation between shortened sleep and a less healthy diet, which surprised researchers since most previous studies suggest that less sleep can lead to poor dietary choices. The takeaway suggests poor sleep alone could be a culprit of weight gain.

2. You lower your “good” cholesterol levels

Those who sleep just 6 hours or less a night also had reduced levels of HDL cholesterol, aka the “good cholesterol,” the same University of Leeds study found. HDL cholesterol helps remove fat from circulation, and having a high HDL cholesterol level can protect against heart disease.

3. You increase your risk for diabetes and heart disease

Sleep disturbances and disruptions in your “internal body clock” can increase your risk for obesity, diabetes, and heart disease, explains Dr. Phyllis Zee, a neurology professor at Northwestern University. “Just like a healthy diet and physical activity, healthy sleep is essential for physical, emotional, and cognitive health,” says Zee, a co-author of the Women & Sleep Guide and a member of the Society for Women’s Health Research Interdisciplinary Network on Sleep.

4. You hinder your body’s ability to control blood sugar

Delving deeper into the correlation between sleep and diabetes, the National Sleep Foundation explains that deep sleep can play a crucial role in regulating glucose in the body. When otherwise healthy people sleep for just 4 hours a night for a week, their ability to break down sugars becomes 40 percent lower than normal, according to the foundation. That’s similar to those who don’t make enough insulin and are at risk of diabetes. Sleeping too little, therefore, can increase your risk for type 2 diabetes, according to the foundation.

5. You have a tougher time problem solving

The immediate consequences of sleep deficiency can affect your brain function, making you less alert, impairing your memory, and even diminishing your problem-solving skills, Zee says.

6. You cave to cravings

Sleep is a powerful tool for weight management. “Getting sufficient sleep — for most of us that means 7 to 9 hours a night — can help keep your appetite in check, curb cravings, and reduce late-night noshing,” explains Michael Breus, Ph.D, who is known as the “Sleep Doctor” and is a SleepScore Labs advisory board member. Tracking your sleep could help you better manage your weight, he suggests.

Several studies have shown that not getting enough sleep leads to increased calorie consumption. A 2016 analysis from researchers at King’s College London found that people who don’t sleep enough consume an average of 385 more calories per day, which is the equivalent of 4 1/2 slices of bread.

7. Your reaction times suffer

Not only does National Sleep Awareness Month fall in March, but so does Daylight Savings (it’s March 11 this year). “Even losing an hour or so of sleep on any given night impacts our functioning, including reducing reaction time and problem-solving ability,” says Russell Rosenberg, Ph.D., former chairman of the National Sleep Foundation and the founder and CEO of NeuroTrials Research, a clinical research site in Atlanta that focuses on sleep-related conditions and other neurological disorders. “So, tasks like driving or operating machinery may be more dangerous.”

8. You might become short on patience

When we’re sleep-deprived, our mood is also affected, says Rosenberg. “We tolerate stress less and relationships can suffer,” he says.

9. You take greater risks without even knowing it

Participants involved in a small study were asked twice a day to choose between obtaining a specified amount of money paid out with a probability or playing it safe with a lower amount of money paid out for sure. Those who were running on five hours of sleep were more likely to make the riskier choice; a higher possible prize, but possibly getting nothing at all, according to the researchers at the University of Zurich and University Hospital Zurich. The researchers believe that when we don’t get enough sleep, it affects the right prefrontal cortex and is correlated with increased risk-seeking behavior.

10. You can become anxious

In fact, just the thought of not sleeping can make someone anxious, explains Jodi J. DeLuca, Ph.D., a licensed clinical psychologist with Erie Colorado Counseling. The anxiety associated with prolonged periods of not being able to sleep can put into motion a vicious cycle of psychological and physical problems, including depressions, she says.

11. You have a hard time shaking negative thoughts

study earlier this year from Binghamton University – State University of New York found that sleeping less than the recommended 8 hours a night is associated with intrusive, repetitive thoughts much like those seen in anxiety and depression. Without enough sleep, people have a hard time shifting their attention away from negative information, the researchers found. They suggested that inadequate sleep is part of what makes negative thoughts stick around and interfere with people’s lives.

12. You have a hard time making decisions

“Our cognitive abilities are more likely to be be impaired by lack of rest,” explains Lorenzo Turicchia, a sleep scientist and biometrics expert with Bedgear. That can affect everything from simple decisions to being able to effectively manage your time.

Pulling an “all-nighter” and not getting any sleep causes people’s brains to lose efficiency, researchers from Texas A&M College of Medicine explain. If you stay up all night, or aren’t getting a recommended amount of sleep, your brain gets weary and there’s a sharp decrease in in performance when it comes to learning and memory tasks.

13. You weaken your immune system

Deep sleep is critical for recharging and strengthening your immune system, says Chris Brantner, a certified sleep science coach with SleepZoo. “If you aren’t spending enough time in deep sleep, your body will have a more difficult time fighting off viruses like the flu,” he explains.

14. You slow your muscle growth

Not getting enough deep sleep can also hinder muscle growth, Bratner explains. During deep sleep, your body releases growth hormones to help build and repair muscle. “So you break muscle down during the day working out, but you grow at night,” he explains.

15. Your skin prematurely wrinkles

When you’re not getting enough shut-eye, your body releases cortisol, a stress hormone that can break down collagen, according to the National Sleep Foundation. Without that collagen, you can get premature wrinkles and your skin can become more crepey or sag.

16. You might feel colder

Sleep is important for body temperature regulations, so when you’re skimping on it, you might feel colder than usual, according to the National Sleep Foundation.

Exactly How Much Sleep Do You and Your Family Members Need?

Sleep recommendations vary depending on age. Here are the most current recommendations from the National Sleep Foundation:

  • Newborns (0-3 months): 14 to 17 hours
  • Infants (4-11 months): 12 to 15 hours
  • Toddlers (1-2 years): 11 to 14 hours
  • Preschoolers (3-5): 10 to 13 hours
  • School-age children (6-13): 9 to 11 hours
  • Teenagers (14-17): 8 to 10 hours
  • Younger adults (18-25): 7 to 9 hours
  • Adults (26-64): 7 to 9 hours
  • Older adults (65+): 7 to 8 hours


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Brittany AnasBrittany Anas is a freelance writer who specializes in health, fitness and travel writing. She also contributes to Men’s Journal, Women’s Health, Trip Savvy, Simplemost, Orbitz, and Eat This, Not That! She spent a decade working at daily newspapers, including The Denver Post and the Daily Camera in Boulder, Colorado, and she is a former federal background investigator. In her free time, Brittany enjoys hiking with her gremlin-pot belly pig mix that the rescue described as a “Boston Terrier” and coaching youth basketball. She also works with domestic abuse survivors, helping them regain financial stability through career coaching. Follower her on Twitter and Instagram.