Sleep deprivation

=== Immunosuppression ===
Among the myriad of health consequences that sleep deprivation can cause, disruption of the immune system is one of them. While it is not clearly understood, researchers believe that sleep is essential to providing sufficient energy for the immune system to work and allowing inflammation to take place during sleep. Also, just as sleep can reinforce memory in a person's brain, it can help consolidate the memory of the immune system, or [[Adaptive immune system|adaptive immunity]].<ref name=":1">{{Cite web|title=Sleep & Immunity: Can a Lack of Sleep Make You Sick?|url=https://www.sleepfoundation.org/physical-health/how-sleep-affects-immunity|access-date=21 January 2021|website=Sleep Foundation|date=26 October 2018 |language=en}}</ref><ref>{{cite journal | vauthors = Irwin MR | title = Sleep and inflammation: partners in sickness and in health | journal = Nature Reviews. Immunology | volume = 19 | issue = 11 | pages = 702–715 | date = November 2019 | pmid = 31289370 | doi = 10.1038/s41577-019-0190-z | s2cid = 195847558 }}</ref>

Sleep quality is directly related to immunity levels. The team, led by Professor Cohen of Carnegie Mellon University in the United States, found that even a slight disturbance of sleep may affect the body's response to the cold virus. Those with better sleep quality had significantly higher blood T and B lymphocytes than those with poor sleep quality.These two lymphocytes are the main body of immune function in the human body.<ref>{{Cite web |title=睡眠好坏直接影响免疫力--健康·生活--人民网 |url=http://health.people.com.cn/n1/2020/0331/c14739-31655366.html |access-date=2023-12-05 |website=health.people.com.cn}}</ref>

An adequate amount of sleep improves the effects of vaccines that utilize adaptive immunity. When vaccines expose the body to a weakened or deactivated antigen, the body initiates an immune response. The immune system learns to recognize that antigen and attacks it when exposed again in the future. Studies have found that people who don't sleep the night after getting a vaccine are less likely to develop a proper immune response to the vaccine and sometimes even require a second dose. {{Citation needed|date=June 2023}} People who are sleep deprived in general also do not provide their bodies with sufficient time for an adequate immunological memory to form and, thus, can fail to benefit from vaccination.<ref name=":1" />

People who sleep less than six hours a night are more susceptible to infection and are more likely to catch a cold or flu. A lack of sleep can also prolong the recovery time of patients in the intensive care unit (ICU).<ref name=":1" /><ref>{{cite journal | vauthors = Prather AA, Janicki-Deverts D, Hall MH, Cohen S | title = Behaviorally Assessed Sleep and Susceptibility to the Common Cold | journal = Sleep | volume = 38 | issue = 9 | pages = 1353–1359 | date = September 2015 | pmid = 26118561 | pmc = 4531403 | doi = 10.5665/sleep.4968 }}</ref><ref>{{cite journal | vauthors = Pisani MA, Friese RS, Gehlbach BK, Schwab RJ, Weinhouse GL, Jones SF | title = Sleep in the intensive care unit | journal = American Journal of Respiratory and Critical Care Medicine | volume = 191 | issue = 7 | pages = 731–738 | date = April 2015 | pmid = 25594808 | pmc = 5447310 | doi = 10.1164/rccm.201411-2099CI }}</ref>