How Sleep Deprivation Affects the Human Body

From Hormone Changes to Weight Gain

Sleep deprivation happens when you do not get enough sleep to meet your body's needs. If you're sleep-deprived, you may feel tired. You can also have other symptoms, because sleep affects your whole body.

You may worry about what will happen if you don't get enough sleep. You might wonder if sleep deprivation will have lasting physical effects on your body. This article will look at what research says about the short- and long-term consequences of sleep deprivation on your health.

Person in bed with pillow over their face
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How Sleep Deprivation Happens

Sleep deprivation occurs when you get less sleep than your body needs to function. You can be sleep-deprived in the short term, as in the day after you slept poorly (acute) or long term (chronic) if you consistently are unable to get enough sleep.

Sleep deprivation can happen in one night or over weeks, months, or even years. If you need 9 hours of sleep to feel rested, you may become sleep-deprived if you regularly get 8 hours of sleep.

How Much Sleep Do I Need?

According to the National Sleep Foundation, most adults need 7 to 9 hours of sleep per night to feel rested. Older adults (age 65 and up) may only need 7 to 8 hours of sleep per night.

The cure for sleep deprivation is to get more sleep. However, that's not always easy to do—the fix for sleep problems depends on what's causing them.

Not getting the sleep you need negatively affects your physical and mental health in a number of ways. You'll feel some of these effects right away, but others may not show up for years.

Brain and Nervous System

The effects of sleep deprivation on the brain can be similar to the effects of alcohol on the brain. In fact, research has shown that driving when you're sleep-deprived can be as dangerous as driving while you're intoxicated.

If you are sleep-deprived, you may have:

Abnormal Reflexes

There are other neurological reflexes that are also affected by sleep deprivation.

You may not have any symptoms related to these changes, but if your healthcare provider were to test your reflexes, they would be abnormal.

For example, you may have:

  • Slow (sluggish) corneal reflexes
  • Oversensitive (hyperactive) gag reflex
  • Oversensitive (hyperactive) deep tendon reflexes


One of the most serious consequences of not getting enough sleep is that it can make you more likely to have a seizure. People who have epilepsy are at a higher risk for seizures when they are sleep-deprived.


You might be more likely to feel feel pain when you're sleep-deprived. Research has shown that sensitivity to heat and pressure pain is higher when we have not had enough sleep.

Other studies have found that people who are sleep-deprived can be more sensitive to pain in their esophagus. That might be one reason why people get heartburn or gastroesophageal reflux disease (GERD) at night.

Sometimes, people with ongoing pain that stems from sleep deprivation are diagnosed with fibromyalgia or other chronic pain conditions.


Not getting enough sleep affects your brain. Some of the changes might not be noticeable to you. However, other effects will be more obvious. For example, you might be more sensitive to pain or have trouble thinking.


Click Play to Learn All About Why You Can't Sleep

This video has been medically reviewed by Sanja Jelic, MD

Vital Signs

Studies have shown that sleep deprivation may cause small changes in your vital signs. Your vital signs are measurements that healthcare providers use to assess your overall health.

Vital signs that can be affected by sleep include:

The changes in your vital signs related to sleep deprivation are usually not very big. For example, your body temperature might only go down a little bit.

Your breathing might also change slightly. When sleep-deprived people do sleep, they tend to have longer and more frequent pauses in their breathing (apnea).


Sleep deprivation can cause small changes in your body temperature, blood pressure, heart rate, and breathing rate.


Sleep deprivation can change how hormones are released by the endocrine glands. Hormones that follow a circadian pattern are the most likely to be affected by sleep.

Growth in Childhood

The effects of sleep loss or disruption in children can be a very big deal. For example, kids that don't get enough sleep may have problems with their growth.

Growth hormone is secreted during slow-wave sleep. In children, this kind of sleep is common in the early part of the night.

However, if this period of sleep is disrupted—either because a child isn't getting enough sleep or they have a condition like sleep apnea—it affects how much growth hormone gets released.

As a result, children may not reach their full growth potential. They might be shorter than they would have been if they had gotten enough growth hormone.

Thyroid Function

Sleep deprivation can also change how the thyroid gland works. Staying awake for a long time increases your energy needs. In turn, your thyroid has to work harder to keep up.

Sleep problems can also be a symptom of thyroid disorders.


If you've ever been told that you look tired, you know that it can be hard to hide when you haven't had a good night's rest.

Sleep deprivation makes you look tired or rundown in a few ways. One is that it can give your skin a sallow, dull look. You may also have bags and dark circles under your eyes.

Your skin needs support from your hormones to rebuild and stay elastic. When you have hormones that aren't working optimally and poor circulation to your tissues, it creates that dull, rundown look of exhaustion.

Other Hormones

Sometimes, the relationship between sleep and your hormones is a vicious cycle. Some hormones are not just affected by sleep deprivation but may contribute to it.

Aside from thyroid and growth hormones, other hormones that are involved in sleep include:

Imbalances in hormones are most often linked to reproductive health problems, like changes to the menstrual cycle and infertility. However, you can also have symptoms related to other body systems that rely on hormones to function.

If your sleep is affecting your hormone levels, you may have symptoms throughout your body. Many of these symptoms are common in people who are going through menopause.

Hormone-related symptoms you might experience include:


When children don't get enough sleep, it can affect their growth. The effects of sleep deprivation on hormones can affect specific organs, like your thyroid. You can also have symptoms in your whole body because many systems need hormones to function.

Long-Term Health Risks

Sleep deprivation can negatively affect your health in both the short and long term. It can even increase your risk of dying.


Not getting enough sleep can affect your metabolism. If your metabolism is not working, it can lead to glucose intolerance and weight gain. Being overtired also makes it less likely that you'll want to take part in regular physical activity.

At the same time, changes in the hormones that make you feel hungry and full can happen when you haven't gotten enough sleep. Eating more and moving less can also lead to weight gain over time. These factors all increase your risk for chronic health conditions like diabetes.


There is some evidence that sleep deprivation has a negative impact on immune function. If your immune system isn't working, you might get sick more often. When you do get sick, you might get more ill and take longer to get better.


Researchers have started to look at whether chronic sleep deprivation may contribute to the risk of cancer. However, more research is needed to prove that there is an important link.


Not getting enough sleep affects your brain. Over time, you might be more likely to develop memory problems and conditions like dementia. Research has suggested that the risk for dementia is especially linked to not getting enough sleep when you're middle-aged.

Can You Die From Sleep Deprivation?

There have been cases of people who died from being completely deprived of sleep, but most of them had a rare condition that causes severe insomnia.

Not getting enough sleep is not likely to cause death directly. Instead, it can increase your risk of dying from other causes.

For example, if you're very tired, you might be more likely to get into a car accident. You might even fall asleep while you're driving.

Being sleep-deprived can also make you more likely to get injured when you're working, exercising, doing a hobby, or even just going about your daily routine.


Over time, sleep deprivation can increase your risk for chronic diseases like diabetes, dementia, and possibly cancer. It can also make your immune system weaker. You aren't likely to die from sleep deprivation directly, but it can increase your risk of accidents which could be fatal.


Sleep deprivation can have serious consequences for your physical and mental health. In the short term, you might have changes to your reflexes and vital signs.

Over time, not getting enough sleep can increase your risk of chronic health conditions and might even increase your risk of dying.

A Word from Verywell

It's important that you do your best to meet your sleep needs. That means figuring out how many hours of sleep you need each night to feel rested.

Beyond the number of hours, the quality of your sleep is also important. If you're not getting quality sleep, it's important to find out why. For example, having sleep apnea and other health disorders can make it harder to get enough good sleep.

If you're having trouble sleeping, talking to a healthcare provider who is board-certified in sleep medicine can be beneficial. They can test you for different sleep disorders and help you find a treatment.

For example, if you have trouble falling asleep or staying asleep, cognitive behavioral therapy for insomnia (CBTI) might help.

Frequently Asked Questions

  • What is sleep deprivation?

    Sleep deprivation is when a person doesn't get enough sleep to feel alert and well-rested. Most adults need 7 to 9 hours of sleep per night.

    Many things can cause sleep deprivation, including stress, anxiety, sound or light sensitivity, sleep disorders, and illness.

  • What are the effects of sleep deprivation on the brain?

    Sleep deprivation can have negative effects on the brain and body. When sleep deprivation affects the brain, you may experience symptoms like irritability, depression, anxiety, poor concentration, forgetfulness, lack of energy, and slow reaction time.

  • Can sleep deprivation cause nausea?

    Sleep deprivation can contribute to gastrointestinal symptoms including nausea, vomiting, abdominal pain, gas, constipation, and diarrhea.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Brandon Peters, MD
Brandon Peters, MD, is a board-certified neurologist and sleep medicine specialist.