25 Terrifying Side Effects of Sleep Deprivation

What do you feel like when you don’t get enough sleep? Groggy, fuzzy-headed, irritable? Starting as early as middle school, we all become accustomed to the feeling of sleep loss – but what you feel is just the teeniest tip of the iceberg of impacts.  

It turns out humans are the only species that intentionally forgoes sleep. For generations, experts have wondered why we even need it. And in today’s busy world, skipping it is a badge of honor – “sleep is for the dead” (and lazy).

But, in recent decades research has uncovered an inconvenient fact for all of us burning the midnight oil or tossing and turning from sleep problems – a shortage of shut-eye negatively impacts our health and well-being in countless ways. To date, after thousands of studies, the better question is there any biological function that isn’t impacted by sleep?

It’s a serious public health issue So serious, the World Health Organization has declared a global sleep loss epidemic. Even more, experts are urging the government and employers to take action and for doctors to start prescribing sleep (not sleeping pills).

One leading sleep expert says it’s a “catastrophic epidemic that’s killing us,” and that policies should be developed that mandate sleep. In an interview with the Guardian,  Professor Matthew Walker, director of the Center for Human Sleep Science at the University of California, Berkeley said “Once you know that after just one night of only four or five hours’ sleep, your natural killer cells – the ones that attack the cancer cells that appear in your body every day – drop by 70 per cent, or that a lack of sleep is linked to cancer of the bowel, prostate and breast, or even just that the World Health Organization has classed any form of night-time shift work as a probable carcinogen, how could you do anything else?”

And, it’s not just cancer.

A study published last year showed that just one week of sleeping fewer than six hours a night resulted in changes to more than 700 genes.

To date, every time researchers wonder, “Hmmm..Do you think sleep is tied to this?” It has been. It impacts us head to toe; inside and out.

Sleep Deprivation

Here are 25 terrifying side effects of sleep deprivation after just one night of shortened sleep…

1. You’ll incur some minor brain damage.

It’s not really as bad as it sounds, but researchers at Stanford University and Washington Medical School have found that just one night of bad sleep is enough to raise levels of amyloid beta - a substance which clumps together creating plaque in your brain that’s toxic to nerve cells. Also, a study in the journal SLEEP found that just one all-nighter resulted in signs of brain tissue loss. Study researcher Christian Benedict, of Uppsala University, said in a statement, “Our results indicate that a lack of sleep may promote neurodegenerative processes.”

2. Your immune system will turn against you.

Just as angsty as an adolescent when you try to cut their shut-eye short, your immune system takes no time turning against you when you lose sleep. Just one night of sleep loss prompts it to trigger tissue-damaging inflammation.

3. You’ll be hungrier and apt to make bad food choices.

Two hormones go hand-in-hand in your body to control feelings of hunger and fullness: ghrelin stimulates your appetite and leptin tells your brain when you’ve had enough to eat. Without enough sleep, ghrelin levels leap and leptin levels lag – which means that not only will you feel hungrier, you’ll also likely eat bigger portions because it’ll take more to feel full. On top of that, studies have found short-term sleep loss makes you crave high-calorie, high-carb foods and makes food smells like potato chips and cinnamon rolls more enticing. It’s the perfect storm for...

4. Your insulin sensitivity will be a similar degree as if you had been on a high-fat diet for 6 months.

You read that right. According to a study out of Cedars-Sinai Medical Center in Los Angeles, one night of bad sleep lowers our body’s sensitivity to insulin in a similar degree as 6 months on a high-fat diet. A decrease in sensitivity to insulin or “insulin resistance” makes your body unable to keep blood sugar stable, which can eventually lead to Type 2 diabetes. (Note: The study was conducted on dogs, but it’s still very telling.)

5. You’ll be a bit dumbed down.

Sleep loss affects your brain in myriad ways. It’s harder to think, focus, remember, and multi-task. Cognitive performance, including complex decision-making skills, innovative thinking, basic math and reaction times are affected by sleep loss. The speed, accuracy, and the ability to multi-task may also be impaired according to some studies.

6. You’ll be less likeable.

We all know how one night of bad sleep can show on our faces, but did you know looking tired makes people less likely to socialize with you? It’s true. In one study, people who had not gotten enough sleep the night before were rated as less attractive and unhealthy looking – both factors that made people want to steer clear of interacting with them. Also, people tend to use more negative words when they are sleep deprived and they are more aggressive and irritable.

7. You’ll be more likely to get into a car accident.

Getting six or fewer hours of shut-eye a night triples your risk of drowsy driving-related accidents, according to the National Sleep Foundation’s Drowsydriving.org. Plus, just one bad night’s sleep can affect a driver’s eye-steering coordination, according to research from Manchester Metropolitan University. It’s a serious safety issue.

Drowsy driving is also a major problem in the U.S. In a National Sleep Foundation survey, 60% of drivers admitted to driving drowsy and 37% admitted to falling asleep at the wheel in the past year. The National Highway Transportation Safety Administration attributes 100,000 accidents, 40,000 injuries and 1550 deaths to drowsy driving, and AAA attributes 17% of all deadly crashes to fatigue. It is estimated that 24 hours of wakefulness makes a driver even more impaired than a blood-alcohol level of .10, meaning that drowsy driving could be even more dangerous than drunk driving.


After about a week of sleep deprivation (give or take a day or two)...

8. You’ll be 4 times more likely to catch a cold.

Sleep is when your immune system builds up its forces for fighting off foreign invaders like bacteria and viruses. Skimp on it and your immune system is left in a weakened state making you more vulnerable in the battle against bugs. One study exposed subjects to a common cold virus and found that those who slept less than 6 hours a night during the prior week were 4 times more likely to get a cold.

9. You could pack on a couple of pounds.

Since one night of bad sleep is enough to make your hunger hormones go haywire, it shouldn’t be too surprising that even more nights can lead to weight gain. One study from the University of Pennsylvania found that subjects who were sleep deprived for five nights in a row gained about two pounds. Another study found that subjects who got only 4.5 hours of sleep for 4 nights had 33% higher levels of ghrelin compared with well-rested people. If you recall from above, too much ghrelin gives you mega-munchies. On top of that, sleep loss makes you more likely to store fat. It’s a double whammy

(On a side note: If you’re dieting and don’t get enough sleep, most of the weight you lose will come from lean body mass, not fat.)

10. You’ll have the cognitive function of a drunk.

You won’t recognize it, but your brain on sleep loss is like your brain on booze. Researchers found that subjects who slept just six hours a night for 14 days (yes, that’s 2 weeks) had the cognitive wherewithal of someone with a 0.1% blood alcohol level. That’s legally drunk.

11. You’ll be more likely to do something you might regret.

There's an area of your brain that's responsible for knee-jerk emotional reactions, called the amygdala. Normally, your prefrontal cortex overrides that reaction, essentially telling your amygdala to chill out because whatever just happened isn't that big of a deal. That doesn't work so well when you're sleep-deprived. After getting four hours of sleep for five nights in a row, subject's amygdalas were about 60 percent more reactive to things meant to make them mad or sad. Meanwhile, communication between the prefrontal cortex and the amygdala broke down. Real-life translation: You're more likely to say or do something you typically wouldn't.

Sleep Deprivation

12. You’ll pave a path for dangerous brain tangles.

After just a handful of nights of sleep disruption, levels of a chemical called tau tick up in your brain. Tau is known to cause tangles in the brain and is also linked to Alzheimer’s disease. http://www.telegraph.co.uk/science/2017/07/10/poor-nights-sleep-triggers-brain-chemical-linked-alzheimers/

13. Your blood sugar levels will be so out of whack that you could be classified as pre-diabetic.

Chronic sleep loss has been tied to diabetes in multiple studies, but a study published in Sleep Medicine Clinics for that even just one week of restricted sleep produces physiological changes that are consistent with the future development of type 2 diabetes.

14. Your sex life will suffer.

Scientists from the University of Chicago found men who get less than five hours sleep a night for a week or longer suffer have far less levels of testosterone than those who get a good night’s rest. Their study found that the levels of the hormone are reduced dramatically to levels more akin to someone 15 years older. Also, The Journal of Sexual Medicine found, a “one hour increase in sleep duration causes a 14% increase in desire for partnered sexual activity.” Can we assume each hour lost causes a 14% decrease? Whether or not that’s accurate, the connection between sleep and sex is clear.


Long-term sleep deprivation makes you a ticking time bomb of health problems…

15. You can become 73% more prone to injuries.

In a 2014 study of competitive young athletes, the correlation between sleep loss and sports injury was staggering. Those who averaged 9 hours of sleep a night had about an 18% chance of injury; those who averaged 8 hours a night had a 35% chance; those who averaged 7 hours a night had about a 60% chance and those who averaged 6 hours of sleep a night had a whopping 73% chance of injury. Most of us aren’t competitive athletes, but many of us are physically active and the connection between sleep loss and injury is more than evident.

16. You’ll age faster.

According to research from the Harvard School of Public Health, sleeping five or fewer hours a night equates to ageing an extra four to five years. Your skin ages twice as fast. Over 60? A study published in Brain, Behavior, and Immunity found sleep deprivation speeds up older adult’s molecular process of biological ageing.

17. You’ll have an impaired intellect.

Sleep is vital to learning and memory. Countless studies have shown if you go without enough for too long and you’ll start making more mistakes, your thinking will slow down, your response time slows down, your short-term recall and memory declines, you won’t be able to learn things as easily, and more. Worse yet, as the authors of one study put it, “cognitive deficits accumulate to severe levels over time without full awareness by the affected individual.”

18. You’ll be more likely to develop a mood disorder like depression and anxiety.

According to the CDC, people that get less than 7 hours of sleep a night are 57% more likely to have depression. In a 2007 study of 10,000 people, those with insomnia were five times as likely to develop depression as those without. In the same study, people with insomnia were 20 times more likely to develop panic disorder (a type of anxiety disorder).

19. Your risk for dementia and Alzheimer's increases.

Sleep is when the brain takes care of housekeeping – like washing away toxins that build up during the day. Lose out on too much and studies show they build up, leading to the plaque and tangles found in those with Alzheimer’s disease and dementia. And it’s not just the amount of sleep, you need the right kind, too. A study in the journal Neurology found that people who get less REM, or dream-stage sleep, may be at higher risk for developing dementia.

20. You’ll be 24% more likely to be obese.

As noted above, just one night of bad sleep can make you hungrier and apt to eat more. Not only can short-term sleep loss lead to increased caloric consumption, but multiple studies have suggested a link between chronic sleep deprivation and increased obesity risk over time. According to the CDC, people that get less than 7 hours of sleep a night are 24% more likely to be obese. And, the American Sleep Association says 3–5% of the overall proportion of obesity in adults could be attributable to short sleep.

21. You’ll have two and a half times the risk of developing diabetes.

Studies from the University of Laval in Quebec show that people who had less than 7 hours sleep had two and a half times the risk of type 2 diabetes or glucose intolerance. This was backed up with research that showed people who get five or less hours of sleep a night are five times more likely to contract diabetes than those who get over seven.

22. You’ll be at risk for all sorts of heart problems.
  • Heart disease - A 2011 European Heart Journal review of 15 medical studies involving almost 475,000 people found that short sleepers had a 48% increased risk of developing or dying from coronary heart disease.
  • Heart attack - One study that examined data from 3,000 adults over the age of 45 found that those who slept fewer than six hours per night were about twice as likely to have a heart attack as people who slept six to eight hours per night.
  • Heart failure - An 11-year Norwegian study of more than 54,000 people, ages 20–89, published in the European Heart Journal, concluded participants with multiple insomnia symptoms had a fourfold increased risk of heart failure compared with those who had no insomnia symptoms.
  • High blood pressure - In the first National Health and Nutrition Examination Survey of 4,810 middle-aged (32-59 years), sleeping less than 5 hours a night was associated with a 60% higher risk of hypertension.
23. You’ll be at least 50% more likely to have a stroke.

According to the CDC, people that get less than 7 hours of sleep a night are 50% more likely to have a stroke. And, preliminary evidence shows if you typically get less than 6 hours, you may have up to a fourfold increased risk for stroke.

24. You’ll increase your risk for all sorts of cancers.

One cancer study of 1,240 participants who underwent colonoscopies found that those who slept fewer than six hours a night had a 50 percent spike in risk of colorectal adenomas, which can turn malignant over time. Another 2012 study identified a possible link between sleep and aggressive breast cancers.

25. You’ll double your risk of death.

In the “Whitehall II Study,” British researchers looked at how sleep patterns affected the mortality of more than 10,000 British civil servants over two decades. The results, published in 2007, showed that those who had cut their sleep from seven to five hours or fewer a night nearly doubled their risk of death from all causes. In particular, lack of sleep doubled the risk of death from cardiovascular disease.



We’ve known for generations that diet and exercise are vital for good health, but now we know sleep is essential, as well. “Now we see sleep as the preeminent force in this health trinity,” writes Professor Walker in his book Why We Sleep. “The physical and mental impairments caused by one night of bad sleep dwarf those caused by an equivalent absence of food or exercise. Sleep is the single most effective thing we can do to reset our brain and body health each day – Mother Nature’s best effort yet at contra-death.”

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