How Sleep Affects the Immune System

How often have you been told to “get some rest” when feeling under the weather?


At the first sign of being sick, most people’s instinct is to get to bed and allow their body time to recuperate. But unfortunately, keeping a healthy, consistent sleep routine is much more challenging when you’re already healthy. 

Given the growing “hustle” culture, it’s normal for people to downplay the importance of getting adequate sleep, especially when confronted with family and financial commitments. In fact, the CDC estimates that about 70 million people nationwide suffer from chronic sleep issues. The problem is, a lack of sleep can lead to a myriad of health problems. There have also been countless studies revealing a clear link between sleep and the immune system. 

In this article, we’ll discuss the powerful role sleep plays in supporting healthy immune function, the effects of sleep deprivation, and how much sleep we need to stay healthy.

Why is sleep important?

Sleep, or a lack thereof, is a critical determinant of our mental and physical well-being and impacts nearly every system in the body. When we sleep, our bodies are able to recharge, supporting healthy brain function and helping lower the risk of chronic health problems. Additionally, getting enough sleep is essential for children and teens to support proper growth and development.

Several important processes also happen during sleep, including muscle repair, protein synthesis, tissue growth, and the release of many vital hormones. Memory is another process closely linked to sleep, as rest allows our minds to sort out the various stimuli we encounter while we’re awake. This triggers changes in the brain that strengthen neural connections, helping us form long-term memories, learn new information, and recall the information later on. 

Finally, sleep can be a powerful stress reliever, helping improve concentration, regulate mood, and sharpen decision-making skills. In contrast, a lack of sleep can reduce our mental efficiency and our ability to cope with stressful situations.

How much sleep do we need?

The amount of sleep you need primarily depends on your age. However, as a general rule, babies need the most rest, followed by young children, teens, and adults. According to the National Sleep Foundation, most healthy adults need between 7 and 9 hours of sleep per night to function properly. 

The ideal amount of sleep also varies depending on the situation. For instance, there are certain cases when people need more sleep, including if they’re experiencing jet lag, working later hours, or recovering from an illness. That said, more sleep isn’t always better. For healthy adults, sleeping more than 9 to 10 hours per night, or “oversleeping,” can result in poor sleep quality, obesity, and an increased risk of developing chronic diseases.

Overall effects of sleep deprivation

Getting adequate sleep is crucial for overall health and well-being. Without it, you may experience various detrimental short-term and long-term issues. 

Short-term effects of sleep deprivation include:

• Decreased cognitive performance
• Inability to concentrate
• Reduced quality of life
• Increased stress
• Mood disorders
• Emotional distress
• Impaired memory

Long-term effects of chronic sleep deprivation include:

• Gastrointestinal issues (acid reflux, constipation, and flatulence) 
• Depression and anxiety
• Severe mood swings
• High cholesterol levels
• High blood pressure
• Hallucinations
• Heart disease
• Diabetes
• Obesity

Impacts of sleep deprivation on immune function

Sleep is essential to the immune system, ensuring it operates at full capacity and preparing it for infections and disease. Furthermore, getting enough sleep each night enables the body to build stronger immunity, respond effectively to vaccines, and react less severely to allergic reactions. 

In contrast, people with severe sleep disorders, such as sleep apnea, insomnia, and narcolepsy, can suffer from an impaired immune system, leaving them more vulnerable to infectious illnesses like the common cold. 

Essentially, sleep is one of the body’s first lines of defense against disease. During sleep, the body produces proteins called cytokines, which fight off infection and inflammation throughout the body. When the body is exposed to dangerous pathogens or experiences chronic stress, it increases the production of these cytokines to counteract illness or avoid it entirely. 

Unfortunately, the body uses significant energy to kick the immune system into high gear and eliminate pathogens. Consequently, less energy is leftover for other bodily functions and everyday activities. This phenomenon is responsible for the lethargic, sluggish feeling we all experience when we’re sick. It’s also why the age-old advice of “getting more rest” is still so valuable to help heal the body and conserve energy to fight diseases.

How to improve sleep and strengthen your immune system

Sleep deprivation can have devasting effects on the immune system. However, getting consistent, good quality sleep can have the opposite effect. Practicing better sleep hygiene is often a simple and achievable way to strengthen your immune response and improve your overall physical and mental health.

Here are several positive changes you can make to improve your sleep routine:

• Stick to a consistent sleep schedule, and maintain a regular bedtime and waketime
• Limit naps to 15-20 minutes, and avoid regularly napping to replace a full night’s sleep
• Limit exposure to artificial light before bed, including light from electronic devices
• Make sure your bedroom is comfortable, cool, dark, and quiet 
• Practice healthy eating habits and stay active during the day
• Avoid caffeine, alcohol, and heavy meals before bed
• Quit smoking and any other method of tobacco use

When to see a doctor

It’s normal to stay up late or have trouble sleeping from time to time. For minor problems like these, start by changing your sleep habits using the tips mentioned above. However, if you see no improvement in the duration or quality of your sleep after a couple of weeks, it’s best to visit a doctor to avoid more serious health issues. 

Additionally, if you wake up frequently throughout the night, sleep often but wake up not feeling rested, or have a partner complaining about your excessive snoring, it’s essential to visit a sleep specialist to help minimize your risk of illness and improve your quality of sleep.



Written by

Kayla Orange

Seasoned healthcare writer with experience writing for various medical professionals and organizations, including general doctors, dentists, plastic surgeons, and sleep specialists.

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