Proper Sleep Could Strengthen Our Immune System, Study Says

A recent study gives a possible reason doctors keep telling their sick patients to “get good rest.” Researchers at the University of Tübingen in Germany discovered that our bodies might be more able to fight infection with healthy sleep.

The researchers focused on T Cells, or lymphocytes (a type of white blood cells) that are integral to our immune response. They found that our T Cells may attach to virus-infected cells more easily while we sleep, thus boosting immune system activity.

Luciana Besedovsky, Ph. D., head of the study, says the results of this study “show a potential fundamental mechanism by which sleep helps us fight infection.”

So what exactly is the connection between our immunity and sleep, and why does sleep play such a critical role in keeping us healthy? We’ll explore how T cells and more help make this relationship possible.

Study figure

Understanding Sleep 

While it may seem like you simply fall asleep at night and wake up in the morning, your body goes through a variety of complicated processes.

As you sleep, you move through different sleep stages in two types of sleep: Non-REM sleep (NREM) and rapid eye movement sleep (REM). You’ll spend 75% of your time sleeping in NREM sleep, which is also known as deep sleep.

Sleep Cycle 

Each of these sleep stages plays a vital role in maintaining your physical and mental health. Here are the different stages and how they impact your body.

  • Stage 1 sleep is a relatively light stage, and it’s fairly easy to be woken up.
  • During Stage 2 sleep, body temperature drops, and breathing and heart rate begin to slow.
  • Stage 3 sleep is described as the “deepest and most restorative sleep.” During this stage, blood pressure drops, muscles relax, breathing slows down and hormones are released.
  • Finally, you reach REM sleep, also known as Stage 4 sleep, which first happens about 90 minutes after falling asleep. This stage is characterized by your eyes moving back and forth — hence the name, rapid eye movement. During REM sleep, your breathing speeds up and becomes irregular, and dreaming can occur as your brain is extremely active. “Signals are sent to the brain’s cerebral cortex, which is responsible for learning, thinking, and organizing information,” the National Institutes of Health (NIH) explains. “Signals are also sent to the spinal cord to shut off movement, creating a temporary inability to move the muscles (‘paralysis’) in the arms and legs.”
  • After a period of REM sleep, one full sleep cycle is complete and Stage 1 sleep starts again.

The Immune System: A Brief Overview

Your immune system is a vast network of organs, white blood cells, proteins or antibodies and chemicals that help protect you from foreign invaders like viruses and bacteria. It helps fight infection, illness and disease.

An immune system that works properly will understand which cells belong to you and which substances are invaders in your body. It then activates and fights off these invaders that can cause illness.

Over time, your immune system will build up antibodies to specific foreign cells (as happens with a vaccine) and quickly remember and destroy them if you’re exposed to them again.

Innate Immunity 

The immune system is made up of two parts: the innate immune system and the adaptive immune system. Your innate immunity is your general immune system that operates as your body’s first line of defense against germs.

Your innate immune system consists of protection from skin and mucous membranes, plus protection from immune system cells and proteins.

Adaptive Immunity 

In the event that your innate immune system isn’t able to destroy germs, your adaptive, or secondary immune system will kick into gear. This type of immunity specifically targets germs that cause infections, and while it works slower than innate immunity, it has the power to “remember” germs.

Adaptive immunity consists of T Cells, B lymphocytes (found in the tissue between the body’s cells) and antibodies in the blood and bodily fluids.

How Does Sleep Support the Immune System? 

Sleep plays a critical role in supporting the immune system.

Research shows that sleep loss is linked to a higher risk for infection, especially when sleeping less than four hours per night for six days.

Plus, poor sleep has been found to change the way your immune system responds, creating a chronic state of inflammation in your body that can make it tough to fight off illness or disease. 

These are other ways that sleep helps support the immune system.

Sleep and Allergies 

Sleeping While Sick

As your body fights off an allergic reaction, it does so by activating the immune system. When you’re constantly dealing with allergies, your immune system has to work twice as hard to protect your body from harmful germs.

While it may come as a surprise, your sleep can actually play a big role in making your allergies better or worse—especially when it comes to your sleep environment. If you’re prone to allergies, be sure to get an allergy-safe mattress

Sleep and Vaccines 

When you’re sick, the time you spend in REM sleep, or the most restorative stage of sleep, can decrease. You might also create fewer antibodies to vaccines like the flu shot if you sleep poorly. Therefore, if you plan on getting a vaccine, it’s essential to prioritize good sleep in the days that follow.

T Cells and Sleep 

Poor sleep can reduce the quality and strength of your T cells, which are essential for fighting off infection. Your body also produces T cells while you sleep, making sleep critical to promoting proper immune system function.

Can Sleep Deprivation Make You Sick? 

Sleep deprivation itself won’t give you a cold, but it can lower your immune system response and make you much more susceptible to getting sick.

Getting seven to nine hours of sleep per night for healthy adults isn’t simply a baseline recommendation. It’s how much time our bodies actually require to “recharge and keep our immune system strong,” UC Health explains.

Tips for Getting a Better Night Sleep

If poor sleep is bringing down your immune system, or you constantly find yourself fighting off viruses, there are steps you can take to get better sleep.

Practicing sleep hygiene is one of the most important things you can do for your sleep. Your sleep hygiene is essentially a set of behaviors, habits and your overall sleep environment, and these factors combined can have a major impact on both your quality and quantity of sleep.

Here are some simple guidelines to follow for a better night of sleep.

  • Create a dark, cool, quiet and comfortable sleep environment
  • Maintain a consistent bedtime (and wake time)
  • Avoid consuming too much caffeine or alcohol, and don’t consume either at least three hours prior to sleep
  • Don’t watch TV, read or work in bed
  • Keep naps short (or avoid naps altogether)
  • Exercise regularly, but not just before bed
  • Take a warm bath or shower before bed
  • Practice meditation or mindfulness

A woman sleeps soundly.
Rachata Teyparsit/Shutterstock

A good night’s sleep is essential to maintaining a strong immune system. If you sleep well and you still find your immune system isn’t working properly, you may want to speak to a healthcare professional to rule out potential underlying conditions that aren’t related to your sleep.


How does sleep affect the immune system?

Getting a full night’s rest of seven to nine hours of sleep helps your body recharge the immune system, allowing it to work properly and fight off pathogens. When you sleep poorly, your immune system doesn’t have time to reset, eventually weakening it if you experience chronic sleep loss.

Can lack of sleep make you sick? 

A lack of sleep itself won’t make you sick, but it can make you much more prone to catching a virus or coming down with an infection since sleep deprivation lowers your immune response.

Does sleep boost your immune system?

While you sleep, your body produces T cells, which are essential to fighting off sickness. Therefore, getting good, consistent quality sleep can help keep your immune system strong.

Ashley Zlatopolsky

Ashley Zlatopolsky is a Detroit-based writer and editor. She writes about health, wellness and fitness for Sports Illustrated, Real Simple, Healthline, Greatist, SELF and more.