How sleep affects the immune system

Photo: Danny G/Unsplash. Design: BOOST Thyroid.

Photo: Danny G/Unsplash. Design: BOOST Thyroid.

A close connection between autoimmune conditions and sleep quality

Sleep is critical for maintaining a healthy body. Disturbed or too little sleep has an impact on the likelihood of developing a number of health conditions, as well as your ability to recover.

Sleep, brain, and the immune system

Approximately 1 in 4 people today experience some sort of sleep disturbance (1). This is a stunning number of people suffering from a lack of one of the body’s crucial functions.

Sleep helps the body redistribute energy resources that are primarily used for brain and muscle work to the immune system. During sleep, the immune cells get out of the circulation, settle in the lymph nodes and start getting ready for the next day of work (2, 3). A similar thing happens in the brain; it not only doesn’t recharge, it also cleans itself up from all the toxic waste of the day, which can otherwise cause inflammation (4).

During sleep cortisol and adrenaline levels drop, while melatonin rises. This helps to counteract inflammation by reducing some of the damaging molecules called reactive oxygen species (ROS) (2).

Sleep creates a unique constellation of immune system and hormones. These are helpful because the active immune system is energy-dependent, and changes in hormone levels during sleep enable our bodies to take extra energy from the muscles and utilize it for building up and maintaining a healthy immune system (4–6). Our hormones are so brilliant, that in the time we are about to wake up, they again rearrange our immune system in order to prepare it to start working from the moment we are up (7, 8).

Lastly, it is not only the brain that determines sleeping patterns. It goes the other way around, too, and the connecting part in this case is the immune system (9). There are two distinct groups of immune cells and molecules which either increase or decrease the amount of deep sleep experienced throughout the night (10–12).

How does poor sleep affect the immune system?

Poor sleep will over time lead to increased inflammation in the body (13, 14), because lack of sleep causes a drop in the production of molecules that counter inflammation (15, 16).

A lack of sleep also makes you vulnerable to viruses and bacteria (17), meaning you might be more prone to catch a cold or flu when you’re sleep deprived (18).

Even if you are only slightly sleep deprived, your body is likely to activate certain parts of the immune system responsible for autoimmune flare-ups (19). This effect is especially strong in women (20, 21).

Sleep is affected by many more biological factors, such as age or the level of physical activity.

A lack of sleep not only causes the immune system to go awry and makes you more susceptible to viral and bacterial infections, it also leads to the breakdown of immune self tolerance (tolerance of our immune system to our own body) which triggers autoimmune diseases (22).

How does inflammation affect sleep?

When talking about autoimmune flare-ups, scientifically we are talking about inflammation happening in the body. Inflammation changes how the brain processes signals, as well as how the brain regulates sleep (23). In the case of ongoing, persistent and chronic inflammation, the body requires much more energy, meaning you have to sleep longer to get enough energy (24).

If an increased amount of certain antibodies are present in the body, you will have more problems sleeping. Some researchers even want to classify narcolepsy as an autoimmune condition (25).

Age as a factor in the sleep-immune system interaction

Age changes how you sleep. Conversely, this means your immune system will change, too. As you approach your 50s, your sleeping patterns will have notably started to change: you will go to bed earlier, take a longer time to fall asleep, sleep for shorter periods of time, and probably wake up several times a night (26).

What can fix the inflammation-sleep loop?

Inflammation can be reduced and sleeping patterns can be improved by practicing mindfulness-based meditation, or through cognitive behavioral therapy (27, 28).

What are the symptoms to look out for?

Sleep deprivation may cause the following:

  1. Daytime sleepiness

  2. Cognitive impairment

  3. Reduced effectiveness of vaccination (you might notice it with flu vaccinations) (29)

  4. Increased obesity and increased appetite (this happens because levels of the anti-hunger hormone leptin are low and levels of the hunger hormone gherlin are increased as a consequence of disturbed and short sleep) (30–32)

  5. Heart problems, including high blood pressure and high risk of heart attack (33–35)

Track your sleep and other symptoms with the BOOST Thyroid app to understand how to improve your health.


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