How Sleep Boosts Your Immune System (And How Poor Sleep May Be Making You Sick)

by | Last updated Apr 22, 2022

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If we learned one thing from the COVID-19 pandemic, it’s the importance of having a healthy immune system. Washing your hands and eating a healthy diet are well-known ways to keep your immunity healthy, but what about getting a good night’s sleep?

Healthy sleep is an integral part of your overall health, but is adequate sleep the key to a strong immune system? Your sleep actually has a significant effect on your immunity and preventing illnesses, so let’s take a look.

How Does Sleep Affect Your Immunity?

Think about sleep as an everyday pitstop for your body. While you sleep, your body and your brain work to recover from the day and to prepare for the next. This includes producing hormones, repairing or regrowing damaged cells, and boosting your immune system.

However, without adequate sleep, your body can’t fully complete its regular nightly maintenance or effectively fight back against illnesses. This makes you more vulnerable to viruses, inflammation, and infections.

Related: Why We Sleep (And Why It’s So Important to Sleep Well)

Sleep Improves T-Cell Function

The first way a good night’s sleep helps create a healthy immune system is in how it maintains T-cells. T-cells— also known as t-lymphocyte or thymocytes— are a type of white blood cell that protects your body against infections and illnesses.

T-cell activation is an important process in which these cells attack and destroy infected cells carrying viruses. Quality sleep is essential for t-cells to function properly and protect your body from disease. On the other hand, inadequate sleep diminishes the efficiency of t-cell responses and puts the body at risk of getting sick.

A study published in the Journal of Experimental Medicine observed the connection between sleep and immune function, and found that participants who had a good night’s sleep had higher levels of t-cell activation than those who didn’t get a full night’s rest.

Those who didn’t get enough sleep also had increased levels of receptor agonists during sleep. These compounds, such as norepinephrine, epinephrine— also known as adrenaline— and adenosine have a suppressive effect on your immune system. 

Additionally, increased levels of these receptor agonists are also associated with adverse health conditions like stress, sleep disturbance, and hypoxia, a condition that results in inadequate oxygen levels in your blood.

Related: How to Use Your Sleep Cycle For Your Best Sleep

Quality Sleep Helps Your Body’s Cytokines Attack Viruses

Another reason sufficient sleep is important for your immunity is that it fosters the release and production of cytokine— a versatile protein that supports the immune system’s response to threats. Cytokines play a key role in managing your immune system when you’re healthy, as well as helping it attack viruses when you’re not feeling well.

The two main jobs of cytokines are promoting cell-to-cell communication, and stimulating cells to move towards areas of inflammation and infection. When you’re sick, cytokine production corresponds with fatigue— this is by design. By making you tired while you’re ill, your body is signaling you to get more rest as it fights illness. On the other hand, sleep loss inhibits the production of cytokines and negatively impacts your body’s immune response.

Sleep and Your Chances of Catching the Common Cold

The strong link between sleep and avoiding the common cold was observed during a study conducted by the University of California, San Francisco. Researchers found that poor sleep— particularly short sleep— was the prime factor in determining whether a person would get sick after being exposed to the cold virus.

The study recorded the sleep habits of 164 volunteers, as well as other lifestyle factors such as stress and alcohol or cigarette use. After a week, the researchers separated the volunteers into hotel rooms and exposed them to the cold virus via nasal drops.

Participants who regularly had a good night’s sleep — between 7 and 9 hours of good quality sleep nightly — were much less likely to catch a cold. Conversely, participants who slept for 6 hours or less each night were 4.2 times more likely to develop a cold than those getting adequate rest were. It dipped even more for participants who got 5 hours of sleep or less— they were 4.5 times more likely to catch a cold.

The study concluded that regardless of age, stress levels, or whether or not they smoked, people who experience chronic sleep loss are at a much higher risk of getting sick.

The human body depends on proper sleep to replenish the proteins and cells it needs to combat diseases. Over time, chronic sleep loss has been connected to an increased risk of serious health conditions including obesity, diabetes, and heart disease. On the other hand, living a long life is associated with not only a healthy lifestyle, but also getting enough sleep regularly.

6 Tips for Getting a Good Night’s Sleep and Boosting Your Immunity

Sleep has been a go-to remedy for those looking to fight back against the common cold and other illnesses for centuries, often going hand-in-hand with grandma’s remedy of a warm bowl of chicken noodle soup. Here are a few of our tips for boosting your immune health through better sleep:

1. Take a Warm Bath

Taking a warm bath with Epsom salts before bedtime can help your body and muscles relax, helping you fall asleep more easily. The hot water can also change your core body temperature, preparing your body for a good night’s sleep. This is because the warm water raises your body temperature, encouraging it to fall as you cool post-bath, mimicking its natural drop as you go to sleep each night.

2. Reduce Alcohol and Caffeine Intake

Consuming alcohol and caffeine too close to bedtime makes it harder to fall and stay asleep. Caffeine’s stimulant effects will keep you awake longer than you intend, and alcohol can relax the muscles in your airways, leading to snoring. Or in the case of too much alcohol, even potentially sleep-disordered breathing.

To avoid this, be sure to stop drinking alcohol within at least two hours of your normal bedtime. With caffeine, avoiding it 6 to 8 hours before bedtime is ideal— this ensures it’s at least at its half-life and moving out of your system by the time you want to go to sleep.

3. Take B Vitamins

B Vitamins encourage good sleep by helping your body regulate its levels of tryptophan. This amino acid helps your body produce melatonin— the sleep hormone that is vital for a good night’s sleep.

4. Drink Herbal Tea

Herbal teas like chamomile, lavender, and passionflower are great choices before bed because they contain little to no caffeine that would keep you up at night. They can also promote healthy sleep by helping you relax and reducing anxiety.

5. Avoid Blue Light before Bed

Blue light from the sun helps keep your circadian rhythm working properly, however, blue light from electronic devices like cell phones and computers hampers your body’s ability to produce melatonin. This makes it harder for your to fall asleep on time, and can lead to poor sleep quality and short sleep. 

To get your best sleep, stop using electronic devices 60 to 90 minutes before bed. Alternatively, you can use blue light blocking products to reduce the amount of blue light you are exposed to when you use your devices. We personally recommend blue light blocking products by Swanwick and Ocushield.

Related: Blue Light and Sleep: How Electronics Can Hurt You

6. Get Tested for Sleep Disorders

If you get a full night’s rest every night but still wake up feeling tired and unrefreshed, then you may have a sleep disorder.

Sleep disorders like insomnia and obstructive sleep apnea can wreak havoc on your sleep. To make matters worse, many people may not even realize they have a sleep disorder. Sleep apnea is especially likely to go undiagnosed because its main symptoms occur while you sleep. Sleep apnea isn’t just a factor of poor sleep— it can contribute to or worsen many health problems, including:

Receiving appropriate treatment for sleep apnea, such as CPAP therapy, can allow your body to return to the deep restorative sleep you need for your body to fight off illness.

Related: 7 Serious Signs You Might Have Sleep Apnea

Getting a good night’s sleep is key to a strong and healthy immune system. Adding and following healthy sleep habits to your nighttime routine will help you get the rest you need each night.

If you’re worried about getting the sleep you need, contact us today at the Sleep Centers of Middle Tennessee. We can help you figure out your symptoms and get you back to the rejuvenating and healthy sleep you need to be at your best each day.


Dimitrov, Stoyan, et al. “Gαs-Coupled Receptor Signaling and Sleep Regulate Integrin Activation of Human Antigen-Specific T Cells.” Journal of Experimental Medicine, The Rockefeller University Press, 4 Mar. 2019,

Prather, Aric A, et al. “Behaviorally Assessed Sleep and Susceptibility to the Common Cold.” Sleep, Associated Professional Sleep Societies, LLC, 1 Sept. 2015,

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