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Sleep and the Immune System

Written by Harshita Parmar

Growing up, we have all heard from our parents, teachers, and other adults that may play an important role in our lives about how important sleep is. There is no doubt that sleep is crucial for the recovery of our body; it is the time we give our bodies to recharge and rejuvenate for the next day. However, a lack of sleep can impact a lot more than just our ability to function properly; it can, in fact, impact neurological function, cardiovascular function, and even the immune system, making you more prone to getting infected by various pathogens.

Why is sleep important for the immune system?

Studies have successfully proven that a lack of sleep is directly correlated to how prone you are to getting sick. It is a lot easier to get sick if you are exposed to a virus, and recovery time can be prolonged due to lack of sleep as well. Other than an increased risk of getting sick, a lack of sleep can also increase the risk of many chronic conditions such as diabetes, obesity, and cardiovascular disease. Getting the recommended 7-8 hours of sleep for adults, 9-10 hours for teenagers, and 10+ hours for younger children is a necessity to ensure that the immune system, as well as the rest of the body systems, functions well. At the same time, getting too much sleep can also have detrimental effects, which include poor quality of sleep due to difficulty falling/staying asleep.

How does lack of sleep exactly affect the immune system?

Lack of sleep directly leads to a decline in the number of T-cells, also known as white blood cells, in your body that fight against infection, in the immune system, which fight against, while inflammatory cytokines, a signaling molecule released by T-cells, increase in the body, causing a greater possibility of getting sick with the cold or flu. Additionally, when we are asleep, our bodies release cytokines, which are molecules that help induce sleep. Some types of cytokines increase when the body is attempting to fight off an infection, and lack of sleep can decrease the production of these cytokines. Lack of sleep also affects how the body fights off an infection. For instance, our body tries to help fight the infection by causing the body to have a fever; fevers help raise body temperature which can help kill bacteria and viruses. Fevers usually are at its highest during the night while we are asleep. When we pull an all nighter, we disrupt the process of the fever occurring, which can delay our recovery time significantly.

Lack of sleep and vaccine response:

Because lack of sleep can affect the way the body responds to illnesses, it can also affect the way we respond to vaccinations. Sleep improves the response for vaccines, showing how crucial it is for adaptive immunity, which works to destroy pathogens. Studies demonstrate that people who do not sleep the night after receiving their vaccine respond to the vaccine poorly, such as lowered vaccine immunity, which can result in less protection against the disease, and potentially may need a second dose to boost the immune system’s response. The body may be unable to develop immunological memory due to sleep deprivation because a good night’s rest enables the balance of immune function which is important for innate and adaptive immunity.


Mann, Denise. “Lack of Sleep and the Immune System.” WebMD, 19 January 2010,

“Sleep and immune function - PMC.” NCBI,

“Sleep & Immunity: Can a Lack of Sleep Make You Sick?” Sleep Foundation, 22 April 2022,

“Definition of T lymphocyte - NCI Dictionary of Cancer Terms - NCI.” National Cancer Institute,

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