Sleep and the immune system

Recall the last time you had the flu. Wasn’t it miserable? Your achy bones, runny nose, sore throat, and heavy cough was unpleasant, led to lost days at work, and/or required at least one visit to the doctor’s office and pharmacy. You wanted to curl up in bed and rest. And you should.



When it comes to getting sick, one of the pillars of getting better is to “get plenty of rest.” Higher fluid intake and medication compliance are other pillars, but sleep is definitely one of the most important ones that many individuals don’t follow through on. While sleep won’t necessarily keep you from getting sick, lack of sleep definitely has an impact on your immune system, which can leave you vulnerable.



In this article, we’ll take a closer look at sleep, the immune system, and how sleep deprivation impacts our immune system’s ability to function at peak levels.


So how much sleep do we need?


According to the National Sleep Foundation (NSF), adults need 7-9 hours of sleep per night and older adults over 65 still require 7-8 hours per night. It’s important to know that Americans get on average 6.8 hours of sleep at night, an hour less than what they were getting in 1942. This leaves about 40% of the population getting less than the recommended amount from the NSF.


While the quantity of sleep is important, the quality of your sleep is just as vital. Your nighttime slumber can be broken down into non-REM (rapid eye movement) and REM stages, with the former also being broken down further into three stages, namely N1, N2, and N3.


How does the immune system work?


The immune system is our body’s natural defense system against infections and illnesses. It has an innate system that combats bacteria, viruses, and other pathogens at that moment. It also has an adaptive system that learns to combat specific threats the body has come in contact with in the past, making the process more streamlined, quicker, and more effective.


The innate system consists of various white blood cells (WBCs) such as basophils, eosinophils, neutrophils, mast cells, and natural killer cells. Once a body comes in contact with a threat, they activate macrophages and dendritic cells to kill of the threat, later activating B and T cells for the adaptive immune system to remember them in the future.


How does sleep deprivation impact the immune system? 


Getting the right amount of quality sleep is good for your health and immune system. But how is that?


When we deprive ourselves of sleep, our body creates fewer cytokines, or proteins secreted by the immune system to regulate inflammation, immunity, etc. A lower amount of cytokines results in us being more susceptible to infections, a less robust response of the immune system, and a longer recovery time.


What is the evidence?


Dr. Aric Prather at the University of California, San Francisco, performed one of the most interesting sleep experiments we’ve come across. He measured the sleep of 150 healthy adults for a week, quarantined them, and proceeded to squirt a hefty dose of rhinovirus live cultures (the common cold virus) into their noses. Participants surprisingly gave full consent and were aware of the study.


Prather then monitored them in the lab for a week. Using blood, saliva, and nasal samples, he could determine objectively if someone caught the cold. The subjects were separated into groups based on how much they slept: less than five hours, five to six hours, six to seven hours, and seven or more hours of average sleep per night. There was a clear relationship with the infection rate and the lack of sleep participants got. The five hours or less group had an infection rate of close to 50%, while the seven hours or more group had a rate of just 18%.


I’ll let you draw your own conclusions.


What to do? 


The healthcare system has its part in treating the sick, and so do governments in establishing good policies for recovery. But the biggest impact will come from us, as individuals who take responsibility in taking care of our immune system. By practicing good sleep hygiene as a common practice, we can create a strong shield against ourselves and limit the amount of times we do get sick and shorten the recovery for when we do get sick.


It’s good for your health, good for your pocketbook, and it alleviates the burden of the healthcare system overall.



Leave a comment

Please note, comments must be approved before they are published