How Sleep Affects Immunity


In recent decades, sleep science has shown that sleep impacts virtually every body system, including the immune system. Research on the links between sleep and physical health make it clear – sleep and immunity are closely intertwined.

The immune system is critical for healing, fighting infections, and protecting against illness. Its relationship with sleep goes both ways. An active immune response (like during an infection) can affect sleep. And getting enough quality sleep bolsters immune function in return.

So while a strong immune system supports better sleep, good sleep also strengthens the immune system. This allows it to work at optimal balance and effectiveness.

On the flip side, not getting enough sleep can disrupt the immune system in both the short and long term. Evidence shows that sleep deprivation can literally make you sick by harming immune defenses.

So supporting healthy sleep is absolutely vital for also maintaining a properly functioning immune system ready to take on viruses, bacteria and more.

How Does the Immune System Work?

The immune system is a complex network protecting the body against illness in multiple ways. Immunity is generally split into two main types:

  1. Innate immunity – Broad, general defenses that form the first line of protection against threats.
  2. Adaptive/acquired immunity – Defenses that build up over time against specific germs. This immunity develops as you’re exposed to diseases.

Together these two arms of the immune system form layers of protection within the body. Innate immunity offers widespread coverage against pathogens. Adaptive zeroes in on tailored responses to germs the body has battled before. This comprehensive defense system works constantly to keep you healthy.

Understanding the Immune System

Our immune system is very complex. An important part of it are white blood cells, also called leukocytes. Their job is to find and get rid of germs and other foreign invaders in our bodies.

Our immune system reacts in two main ways – innate (immediate) and adaptive (learned over time). This allows us to safely interact with our environment every day.

When a white blood cell detects a harmful germ, it releases proteins called cytokines. These act as messengers to tell other white blood cells to prepare to attack.

Cytokines also cause things like swelling or redness at the site of an infection. This helps contain the invaders. Other chemicals like histamine are involved in these immune reactions too.

So in summary – white blood cells, cytokines and chemicals work together as part of our innate and adaptive immune responses. This protects us by fighting off germs we encounter.

Balanced Immune Response

The immune system works best when it’s in balance. It needs to be strong enough to detect and fight threats. But it also needs to be regulated, so the body isn’t constantly inflamed or in “attack mode.”

When there is an injury or infection, the immune system kicks into action. It causes reactions like redness, swelling, fever, fatigue, and pain at the site. These are signs that the immune troops are attacking the threat.

But these inflammatory responses need to be controlled. The immune system can’t be overactive all the time. It needs to return to a balanced state when the threat is gone.

In summary, the immune system works hard to defend against germs and infections. But it also needs to know when to relax. Finding this balance is key to good immune function overall.

How Does Sleep Affect the Immune System?

Getting enough good sleep is very important for a healthy immune system. When we sleep well, it allows our immune defenses – both innate and adaptive – to function at their best.

Good sleep also helps us respond better to vaccines. And it can mean less severe allergic reactions.

On the flip side, chronic sleep problems like insomnia, sleep apnea, and disrupted sleep rhythms can interfere with normal immune function.

So quality sleep helps “recharge” and balance our immune system. But sleep disorders can throw off that balance and disrupt immune defenses.

In summary, aim for sufficient, high-quality sleep to support a properly functioning immune system. And treat any sleep disorders, as they can negatively impact immunity.

How Sleep Affects Immunity
How Sleep Affects Immunity

Sleep and Innate and Adaptive Immunity

Research shows that sleep is very important for both innate and adaptive immunity.

During sleep, some parts of the immune system become more active. For example, production of inflammation-causing cytokines goes up. This is driven by sleep and the body’s 24-hour circadian rhythm.

This increased immune activity during sleep may help the body recover from illness or injury. It strengthens innate and adaptive immunity as the body fights infection or repairs wounds.

Interestingly, this inflammation happens even without active injury or sickness. Research suggests it strengthens immune memory, which is part of adaptive immunity.

Like sleep helps consolidate memories in the brain, it seems to help the immune system reinforce its ability to recognize and respond to threats.

Experts think this happens during sleep for several reasons:

  • Sleeping uses less energy, freeing it up for immune tasks
  • Inflammation at night avoids harming daytime performance
  • Melatonin counters inflammation stress

This immune activity self-regulates, winding down as sleep ends. Quality sleep provides the right balance for immunity.

Sleep and Vaccines

Studies clearly show sleep improves vaccine effectiveness, demonstrating the immunity benefits of sleep.

Vaccines work by introducing a weakened antigen to train the immune system to recognize and attack the real thing later.

Research found weaker immune response to vaccines when people didn’t sleep the night after getting vaccinated. For some vaccines, this meant needing an extra dose.

Those who habitually sleep less than 7 hours a night also tend to have reduced vaccine effectiveness. Their bodies may not develop full immune memory.

Sleep and Allergies

Growing evidence links sleep and allergies.

The circadian rhythm helps regulate the body’s response to allergens. Disrupted rhythms can increase allergy risk and severity.

Studies also show sleep deprivation makes people more susceptible to allergy attacks. It lowers the exposure level needed to trigger an attack.

Can Sleep Deprivation Make You Sick?

Not getting enough sleep can negatively affect your immune system and make you more likely to get sick.

Lack of sleep has been linked to both short-term illnesses like colds and flu, as well as long-term health problems like diabetes and heart disease. Researchers believe this is because sleep deprivation disrupts normal immune function.

Studies show people who sleep less than 6-7 hours per night are more prone to infections. Insufficient sleep also makes you more susceptible to catching colds and flu. In hospitals, patients who don’t get enough sleep may have slower wound healing.

Lack of sleep is tied to chronic diseases too. In healthy sleep, inflammation at night resolves by morning. But with insufficient sleep, inflammation persists abnormally.

This ongoing mild inflammation contributes to higher risks of diabetes, heart disease, pain, neurodegenerative disorders, and possibly cancer. It may also relate to the high rates of depression in people with sleep disorders.

Unfortunately, the immune system does not seem to “adapt” to ongoing sleep deprivation. The inflammation can become chronic, further worsening long-term health.

In summary, lack of sufficient sleep negatively impacts immunity in both the short and long-term. Adequate high-quality sleep is important to maintain a properly functioning immune system.

How the Immune System Affects Sleep

The immune system also affects sleep in several ways when you are sick.

Infections trigger immune responses like fatigue and sleepiness. This is why people tend to sleep more when they’re ill – the immune system is signaling the need for rest.

The quality of sleep changes too. Infections increase time spent in deep non-REM sleep. This slows body processes, freeing up energy for immunity to fight infection.

Fever is another key immune response. Higher body temperature boosts immune defenses and makes the body less hospitable to germs.

Experts believe infection-related sleep changes facilitate fever. Deep sleep lowers metabolism, enabling a higher fever. And shivering raises temperature, but can’t happen in REM sleep. So REM sleep decreases.

With fevers, people often experience “fever dreams” – more frequent nightmares. This results from fragmented REM sleep during infection.

So in summary, the immune system alters sleep patterns to optimize its germ-fighting abilities when you’re sick. This demonstrates the close two-way interactions between sleep and immunity.

How Can You Improve Sleep and Strengthen Your Immune System?

Getting enough good quality sleep each night is important for strengthening your immune system.

Improving sleep often starts with habits and routines – known as good sleep hygiene. Steps like keeping a regular sleep schedule and not using phones in bed can make it easier to sleep well.

People with chronic sleep issues or recurring sickness should talk to their doctor. They can identify underlying causes and recommend solutions.

Those with insomnia may benefit from cognitive behavioral therapy for insomnia (CBT-I). It changes negative thoughts about sleep and promotes healthy sleep habits. Studies show it reduces inflammation too.

Relaxation techniques like yoga, tai chi, and meditation can also enhance sleep and immunity. Research finds they improve vaccine response and lower inflammation markers.

The bottom line is prioritizing sufficient, high-quality sleep through good sleep hygiene and treatment of sleep disorders. This can go a long way in supporting a properly functioning immune system.

Smith-Magenis Syndrome and Sleep

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  • Milly

    Milly is a mechanical engineer residing in Canada who loves to disassemble and rebuild the latest tech in her spare time. Her passion for understanding how electronics work combined with her engineering expertise allows Milly to provide in-depth,nuts-and-bolts reviews on everything from smartphones to high-end TVs.

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