by Dr. Robert Rosenberg, Medical Adviser to SoClean, June 30, 2020.
Since many people are looking for ways to stay healthy during the COVID-19 crisis, it’s a good time to highlight one of the most critical factors in supporting your immune system: healthy, adequate sleep.
Scientists have long known about sleep’s importance in helping the body to protect itself from viruses and other pathogenic invaders. But a study from 20121 underscores just how critical it can be.
Researchers recruited 164 people, who subsequently underwent health screenings and answered questions about their stress levels, alcohol and cigarette use, and other health determinants. Researchers also directly measured subjects' sleep duration and quality with a watch-like sensor that measured their movement throughout the night.
The subjects were then quarantined and exposed to a mild form of the common cold virus through nasal drops. The researchers discovered that people who slept on average less than six hours a night, the week before the virus exposure, were 4.2 times more likely to catch a cold—independent of other risk factors—compared with those who got at least seven hours of sleep. And people who slept less than five hours per night were 4.5 times more likely to come down with the virus.
Of course, there’s no research specifically tying good sleep to resistance to the new coronavirus. But it’s clear that sleep deprivation makes us far more susceptible to developing a viral infection generally. (Not to mention that sleep is important for a host of other healthy body systems2.)
So exactly how does adequate, healthy sleep support the immune system? Here are just a few of the findings from the fascinating research that’s been done on this subject:
Sleep turns off the stress that hinders “killer” T-cells. These cells, also called cytotoxic T-cells, destroy virus-infected cells to stop them from replicating. They do this with the help of proteins called integrins, which allow the T-cell to stick to the virus and attack it. A study by German researchers3 compared the immune response of sleeping people with that of people kept awake during the night. Subjects who were not sleeping had T-cells with less activated integrins, which were less effective at fighting off viruses. The researchers determined that this is due to greater amounts of stress hormones (epinephrine, norepinephrine, prostaglandin and adenosine) that the body produces while we are awake.
Sleep allows immune cells to communicate better. Cytokines are a category of proteins that allow cells to communicate and interact with one another—and that includes the “killer” cells just mentioned that are responsible for destroying viruses in the body. Many studies4 have established a clear link between sleep deprivation—usually defined in research as less than six hours per night—and reduced production of certain cytokines.
Sleep improves antibody response. Antibodies are another type of blood protein that can bind to a virus and kill it. Once the body is exposed to a certain pathogen, it produces antibodies specific to that threat, meaning that it “recognizes” the invader and knows how to fight it off, which normally results in immunity. A study5 of people receiving the vaccine for hepatitis B found that subjects who were sleep-deprived the week before receiving the vaccination had a much poorer antibody response. In fact, in many cases, the researchers felt the antibody response produced in those people would not be strong enough to inhibit the hepatitis B virus.
One final note: If stress and anxiety are hurting your ability to sleep during this uncertain time, you’re certainly not alone. But as I think the above research makes clear, it’s vitally important to do whatever it takes to get an adequate amount of quality sleep.
Find some more ideas about how to maintain your schedule and reduce your stress levels here.
Sleep, “Behaviorally Assessed Sleep and Susceptibility to the Common Cold,” September 2015. https://www.ncbi.nlm.nih.gov/pubmed/26118561
American Sleep Association, “How Important Is Sleep?” accessed June 2, 2020. https://www.sleepassociation.org/about-sleep/how-important-is-sleep/
Journal of Experimental Medicine, “Gas-coupled receptor signaling and sleep regulate integrin activation of human antigen-specific T cells,” 2019. https://rupress.org/jem/article/216/3/517/120367/G-s-coupled-receptor-signaling-and-sleep-regulate
Brain, Behavior, and Immunity, “Influence of sleep deprivation and circadian misalignment on cortisol, inflammatory markers, and cytokine balance,” June 2015. https://www.sciencedirect.com/science/article/abs/pii/S0889159115000069
Sleep, “Sleep and Antibody Response to Hepatitis B Vaccination,” August 2012. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3397812/