Your body needs sleep, just as it needs air and food to function at its best. During sleep, your body heals itself and restores its chemical balance. Your brain forges new connections and helps memory retention. Without enough sleep, your brain and body systems won’t function normally. It can also dramatically lower your quality of life. A review of 16 studies found that sleeping for less than 6 to 8 hours a night increases the risk of early death by about 12 percent.The obvious signs of sleep deprivation are:
- excessive sleepiness
- daytime fatigue
Stimulants like caffeine aren’t enough to override your body’s profound need for sleep. Behind the scenes, chronic sleep deprivation can interfere with your body’s internal systems and cause more than just the initial signs and symptoms listed above. Read on to learn exactly how sleep deprivation affects specific body functions and systems.
Central nervous system
Your central nervous system is the information highway of your body. Sleep is necessary to keep it functioning properly, but chronic insomnia can disrupt how your body usually sends 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 come at a delay, decreasing your coordination skills and increasing your risks 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 there. A lack of sleep can also trigger mania in people who have manic depression. Other psychological risks include:
- impulsive behavior
- suicidal thoughts
You may also end up experiencing microsleep in the day. During these episodes, you’ll fall asleep for a few seconds or minutes 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 due to trips and falls.
While you sleep, your immune system produces protective, infection-fighting substances like cytokines. It uses these substances to combat foreign invaders such as bacteria and viruses. Cytokines also help you sleep, giving your immune system more energy 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. It may also take you longer to recover from illness. Long-term sleep deprivation also increases your risk for chronic illnesses like diabetes and heart disease.
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 the quality of your sleep. 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.
Along with eating too much and not exercising, sleep deprivation is another risk factor for becoming overweight and obesity. 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 night. A lack of sleep can also contribute to weight gain by making you feel too tired to exercise.Sleep deprivation also prompts your body to release higher levels of insulin after you eat. Insulin controls your blood sugar level. Higher insulin levels promote fat storage and increase your risk for type 2 diabetes.
Sleep affects processes that keep your heart and blood vessels healthy, including 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 published in the European Journal of Preventive Oncology linked insomnia to an increased risk of heart attack and stroke.
Hormone production is dependent on your sleep. For testosterone production, you need at least three hours of uninterrupted sleep, which is about the time of your first REM 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 build muscle mass and repair cells and tissues. The pituitary gland releases growth hormones continuously, but sleep and exercise also help induce the release of this hormone.