What sleep deprivation really does to your body

Wondering if your night time habits are wearing on your wellbeing? Learn the causes, symptoms and side effects of sleep deprivation to better understand how a lack of shut-eye can impact your life.

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Whatever the cause, many of us just don’t get enough sleep. While an occasional sleepless night may only have a minor effect on how someone feels and functions, chronic sleep deprivation can have a major impact on a person’s health, says sleep specialist W. Chris Winter, MD.

Read on as medical experts share the signs and effects of sleep deprivation—plus research-proven tips to help you score a better night’s rest.

What is sleep deprivation?

Sleep deprivation is a condition where you don’t get enough rest—either occasionally or chronically, says neurologist, Fariha Abassi-Feinberg, MD. Everyone’s “adequate amount” varies; some people require nine hours of shut-eye a night, while others feel fine with seven, Dr. Abassi-Feinberg says. If you don’t meet your body’s requirement, you are experiencing sleep deprivation—and likely the physical and mental symptoms that tend to come with it.

What causes sleep deprivation?

Sleep deprivation can be caused by lifestyle circumstances (including family demands and work schedules), as well as medical conditions (such as depression, sleep apnoea and hormone imbalances.) Medications, caffeine and alcohol can also interfere with sleep.

Sometimes, though, many of us simply drop the ball on prioritising sleep, Dr. Abassi-Feinberg says. “We’re scrolling through social media or watching a show on Netflix, which pushes back our bedtime, cutting into our rest”, she says.

Symptoms of sleep deprivation

If you feel beat and can’t stop yawning throughout the day, those are telltale signs that you’re not getting enough sleep, Dr. Winter says. But fatigue isn’t the only signal that you’re short on sleep. Other possible signs include:

  • Difficulty remembering things: Can’t find your keys (again)? That late-night scroll may be to blame. The brain processes memories during sleep, Dr. Winter says, so falling short on sleep can affect both short- and long-term memory.
  • Altered decision making: Don’t be surprised if you regret a choice you made when you were exhausted. Research shows that people are more likely to make risky or poor decisions when they’re sleep deprived.
  • Trouble regulating emotions: Even one or two nights of tossing and turning can affect your mood, Dr. Abassi-Feinberg says. When you’re sleep deprived, you may have a shorter fuse and feel crankier, sadder and more stressed.
  • Difficulty staying focused: Sleep deprivation decreases activity in the part of the brain that controls attention and alertness, according to a study published in the journal Neuropsychopharmacology.

Physical effects of sleep deprivation

Not getting enough sleep night after night can take a toll on the body. Sleep deprivation may increase a person’s risk of the following conditions:

  • Weakened immune system: Sleep loss can reduce the function of key immune cells. That may be why one study found that people who slept six or fewer hours a night for one week were four times more likely to catch a cold than those who got more sleep.
  • Type 2 diabetes: Sleep deprivation may affect the body’s production of and sensitivity to insulin, a hormone that regulates blood sugar levels. A small study of nine healthy adults found that one night of serious sleep deprivation (subjects got just 4 hours of shut-eye) was enough to set off insulin resistance, a risk factor for type 2 diabetes.
  • High blood pressure: People who reported sleeping less than six hours on average a night were 66% more likely to have hypertension than those who slept longer, according to a large study published in the journal Sleep.
  • Heart disease: Not getting enough sleep doesn’t just increase the risk of high blood pressure; it’s correlated with inflammation, as well—and these conditions make a person more likely to develop heart disease.
  • Stroke: Insufficient sleep triggers processes that may lead to atherosclerosis, fatty build-up in blood vessels that can cause a stroke. Researchers at the University of Alabama at Birmingham found that the risk of stroke was four times greater for people who slept six or fewer hours per night than it was for those who slept at least seven hours.

Mental effects of sleep deprivation

Sleep loss affects the way the brain works, Dr. Winter says, which may lead to the following:

  • A quick temper: Sleep-deprived people react to frustrating situations with more stress and anger. Preliminary research points to a possible connection in grey matter, where sleep deprivation is linked with greater activity in the amygdala, an area of the brain tied to feelings of agitation.
  • Increased anxiety: Worry and sleep deprivation are intertwined in what scientists call a “bidirectional relationship.” Stressful thoughts can keep you up at night and research shows that sleep problems can set the stage for anxiety, perpetuating a cycle.
  • Impaired cognitive performance: Not getting enough shut-eye may reduce a person’s attention span, memory and motivation, according to research published in the journal Neuropsychiatric Disease and Treatment.
  • Increased sadness and depression: There’s a strong link between sleep issues and depression. One study found that 40% of people with depression have trouble falling and/or staying asleep. Research suggests that sleep deprivation can also affect brain chemistry and hormones, which may negatively affect a person’s mood.

Can lack of sleep affect your weight?

There’s definitely a connection between sleep and the scale, but it’s not as direct as “sleep more, weigh less.” Sleep loss increases levels of ghrelin, a hormone connected to hunger, and decrease levels of leptin, a hormone linked to feelings of fullness. This may lead sleep-deprived people to eat more than they would if they were well rested, Dr. Abassi-Feinberg says. Sleep loss also affects decision making and cravings, which can influence eating patterns and lead to poorer food decisions.

A review of research found that, on average, people eat an extra 384 calories (1600 kJ) per day when they’re sleep deprived compared to when they’re well rested—without expending more energy. If that happens often enough, it stands to reason that weight gain could result. So while there isn’t a direct correlation between how much you sleep and how much you weigh, it’s clear that shut-eye can affect the number on the scale.

Is there a treatment for sleep deprivation?

Let it be said, a third cup of coffee isn’t a cure for sleep loss. The only way to truly combat the effects of sleep deprivation is to get the shut-eye your body requires. Seven to nine hours is the go-to recommendation for adults, but the ideal amount of sleep required can vary between adults. To find out your ideal amount, note your bedtime and let yourself wake up naturally without an alarm on a few occasions. “That’s usually the amount of sleep you need,” Dr. Abassi-Feinberg says.

It also helps to ask yourself some key questions; Do you wake up feeling refreshed? Or are you still tired throughout the day, less focused and productive than you’d like? Tracking your responses against your sleep schedule may reveal insights unique to you.

Tips for preventing sleep deprivation

Once you’ve got a sleep goal in mind, the research-based strategies below can help you reach it. But before you dive in, you might want to check in with your doctor first. Sleep deprivation that’s caused by a medical issue—such as depression, sleep apnoea, or a prescription medication—may call for an approach beyond lifestyle modifications.

  • Create a sleep-friendly bedroom environment: Make your room dark and cool, Dr. Abassi-Feinberg says, since darkness helps trigger production of the hormones that support sleep and most people snooze better in cooler temperatures. Remove or dim any light sources, such as clocks and chargers. Also consider your mattress and pillow. If you wake up feeling achy, it might be time to replace them.
  • Try to cut back on alcohol: Although alcohol is a sedative, it actually suppresses the restorative stages of sleep, Dr. Winter says. Research shows that alcohol decreases sleep quality and duration. If you’re going to have a drink, try to have your last one at least four hours before bedtime so your body has a chance to metabolise the alcohol before bed.
  • Create a bedtime routine: Doing the same relaxing things each night signals to your brain that it’s time to switch into sleep mode. Try reading a book, taking a shower, or listening to soft music, Dr. Abassi-Feinberg says. Listening to a meditation can also be a great way to unwind - remember there are a number of meditations by Breethe in the WW app.
  • Try to stick to a set bedtime: Aim to go to bed around the same time every night—yes, even on weekends! Research shows that a consistent bedtime is linked with better sleep and less daytime sleepiness.
  • Switch off screens: The blue light emitted from phones, tablets, computers and TVs suppresses melatonin, a hormone important for helping you fall asleep. “Ideally, turn off devices 90 minutes before bedtime,” Dr. Abassi-Feinberg says.
  • Get active: Walk, bike, dance—whatever gets you moving—on most days. Research shows doing at least 30 minutes of moderate-intensity activity, five days a week, improves sleep quality and length. If you can get active outdoors, even better. Sunlight helps regulate your internal body clock, Dr. Winter says, which can help you sleep more soundly at night.
  • Skip the afternoon latte: Although everyone is different, it usually takes about six to eight hours to metabolise caffeine, Dr. Abassi-Feinberg says. Time your last coffee of the day accordingly, or switch to decaf if you don’t want to give up a late afternoon cup.

The upshot: Adequate sleep is key for good health

Feeling tired and foggy isn’t a normal part of life—it can mean you’re not getting the amount of rest your body needs. Short-changing sleep can affect a person’s mood and ability to handle stress, Dr. Winter says and research shows that sleep deprivation may also increase the risk of experiencing certain health issues. The good news, experts have found that making a few lifestyle changes can often help people get the sleep they need. If simple modifications don’t make a difference, check in with your doctor or a sleep specialist to explore other medical issues that may be involved.