Not getting enough sleep drains your mental abilities and puts your physical health at risk. Science has linked inadequate slumber with a number of health problems, from weight gain to a weakened immune system.

If you’ve ever spent a night tossing and turning, you already know how you’ll feel the next day — tired, cranky, and out of sorts. But missing out on the recommended 7 to 9 hours of shut-eye nightly does more than make you feel groggy and grumpy.

The long-term effects of sleep deprivation are real.

Central nervous system

Your central nervous system is the main information highway of your body. Sleep is necessary to keep it functioning properly, but chronic insomnia can disrupt how your body usually sends and processes information.

During sleep, pathways form between nerve cells (neurons) in your brain that help you remember new information you’ve learned. Sleep deprivation leaves your brain exhausted, so it can’t perform its duties as well.

You may also find it more difficult to concentrate or learn new things. The signals your body sends may also be delayed, decreasing your coordination and increasing your risk for accidents.

Sleep deprivation also negatively affects your mental abilities and emotional state. You may feel more impatient or prone to mood swings. It can also compromise decision-making processes and creativity.

If sleep deprivation continues long enough, you could start having hallucinations — seeing or hearing things that aren’t really there. A lack of sleep can also trigger mania in people who have bipolar mood disorder.

Other psychological risks include:

You may also end up experiencing microsleep during the day. During these episodes, you’ll fall asleep for a few to several seconds without realizing it.

Microsleep is out of your control and can be extremely dangerous if you’re driving. It can also make you more prone to injury if you operate heavy machinery at work and have a microsleep episode.

Immune system

While you sleep, your immune system produces protective, infection-fighting substances like antibodies and cytokines. It uses these substances to combat foreign invaders such as bacteria and viruses.

Certain cytokines also help you to sleep, giving your immune system more efficiency to defend your body against illness.

Sleep deprivation prevents your immune system from building up its forces. If you don’t get enough sleep, your body may not be able to fend off invaders, and it may also take you longer to recover from illness.

Long-term sleep deprivation also increases your risk for chronic conditions, such as diabetes mellitus and heart disease.

Respiratory system

The relationship between sleep and the respiratory system goes both ways. A nighttime breathing disorder called obstructive sleep apnea (OSA) can interrupt your sleep and lower sleep quality.

As you wake up throughout the night, this can cause sleep deprivation, which leaves you more vulnerable to respiratory infections like the common cold and flu. Sleep deprivation can also make existing respiratory diseases worse, such as chronic lung illness.

Digestive system

Along with eating too much and not exercising, sleep deprivation is another risk factor for becoming overweight and obese. Sleep affects the levels of two hormones, leptin and ghrelin, which control feelings of hunger and fullness.

Leptin tells your brain that you’ve had enough to eat. Without enough sleep, your brain reduces leptin and raises ghrelin, which is an appetite stimulant. The flux of these hormones could explain nighttime snacking or why someone may overeat later in the night.

A lack of sleep can also make you feel too tired to exercise. Over time, reduced physical activity can make you gain weight because you’re not burning enough calories and not building muscle mass.

Sleep deprivation also causes your body to release less insulin after you eat. Insulin helps to reduce your blood sugar (glucose) level.

Sleep deprivation also lowers the body’s tolerance for glucose and is associated with insulin resistance. These disruptions can lead to diabetes mellitus and obesity.

Cardiovascular system

Sleep affects processes that keep your heart and blood vessels healthy, including those that affect your blood sugar, blood pressure, and inflammation levels. It also plays a vital role in your body’s ability to heal and repair the blood vessels and heart.

People who don’t sleep enough are more likely to get cardiovascular disease. One analysis linked insomnia to an increased risk of heart attack and stroke.

Endocrine system

Hormone production is dependent on your sleep. For testosterone production, you need at least 3 hours of uninterrupted sleep, which is about the time of your first R.E.M. episode. Waking up throughout the night could affect hormone production.

This interruption can also affect growth hormone production, especially in children and adolescents. These hormones help the body build muscle mass and repair cells and tissues, in addition to other growth functions.

The pituitary gland releases growth hormone throughout each day, but adequate sleep and exercise also help the release of this hormone.

Infographic on the effects of sleep deprivation on the body

The most basic form of sleep deprivation treatment is getting an adequate amount of sleep, typically 7 to 9 hours each night.

This is often easier said than done, especially if you’ve been deprived of precious shut-eye for several weeks or longer. After this point, you may need help from your doctor or a sleep specialist who, if needed, can diagnose and treat a possible sleep disorder.

Sleep disorders may make it difficult to get quality sleep at night. They may also increase your risk for the above effects of sleep deprivation on the body.

The following are some of the most common types of sleep disorders:

To diagnose these conditions, your doctor may order a sleep study. This is traditionally conducted at a formal sleep center, but now there are options to measure your sleep quality at home, too.

If you’re diagnosed with a sleep disorder, you may be given medication or a device to keep your airway open at night (in the case of obstructive sleep apnea) to help combat the disorder so you can get a better night’s sleep on a regular basis.

How can insomnia affect you?

Temporary insomnia may increase your fatigue and perceived stress levels. Persistent sleep deprivation may lead to:

  • memory and learning challenges
  • emotional distress
  • increased production of stress hormones
  • irritability and other mood changes
  • decreased productivity
  • difficulty with focus and concentration
  • worsening of existing symptoms of mental or physical health
  • increased blood pressure

What are the long-term effects of insomnia?

In the long term, a chronic lack of sleep can have a negative effect on your heart health and metabolism. Research shows long-term insomnia may be associated with a higher chance of obesity, type 2 diabetes, hypertension, and some cancers.

How does insomnia affect the brain?

Lack of sleep may lead to cognitive challenges. Cognitive refers to thought processes related to learning, remembering, planning, and interpreting information.

At a glance, insomnia may impact:

  • attention
  • working memory
  • amygdala reactivity, making it more difficult for you to perceive ranges of emotions
  • decision-making processes
  • learning ability

What are the 5 stages of sleep deprivation?

The 5 stages of sleep deprivation refer to the amount of time you go through without sleeping. After each stage, additional negative side effects begin to occur. The times are:

  1. 24 hours
  2. 36 hours
  3. 48 hours
  4. 72 hours
  5. 96 hours