After the year we have been through, the importance of keeping a strong immune system is clear. If you had a grandma like mine, you might have been advised when you were young to wash your hands frequently, eat right (i.e., eat those colorful vegetables), exercise, and get enough sleep to stay healthy.
Still, great words of wisdom and the science of sleep medicine continue to find more reasons why that suggestion to get enough sleep improves our immune system.
In the first few hours of sleep, where deep sleep becomes concentrated, growth hormone and prolactin are released. Under their influence, the immune system remains enhanced. Cells presenting antigens, or portions of infectious agents, will enable the T helper cells to develop immunity to the agent through activating B cells to make antibodies and increase cytotoxic T cells. During the process of a deep sleep, the memory of our immune system enhances and stores. In other words, deep sleep is an important time for our immune system’s training and the production of tools to fight infections.
Another reason sufficient sleep boosts the immune system may be through melatonin, which is not only one of the most powerful antioxidants in our body but also activates other antioxidants. A study of the Cleveland Clinic COVID-19 registry showed that patients who used melatonin had nearly a 30% less likelihood of testing positive for COVID-19. That risk reduction increased to 52% lower risk in African Americans.
Several studies have looked at the effect of sleep deprivation on the body’s response to a vaccine. Subjects getting 4 hours of sleep before and after the flu vaccine had less than half the antibody response than those who had 8 hours of sleep per night. Studies of short sleep duration have also shown less response to hepatitis B vaccination.
Other studies have looked at the susceptibility of catching a cold, and individuals sleeping less than 7 hours are more likely to develop colds.
In addition to getting enough sleep, having a healthy sleep is also essential. Obstructive sleep apnea appears to increase the risk of getting COVID-19 and of having more severe complications – so if you snore, now is a great time to consider being evaluated.
March 14-20 is Sleep Awareness Week and a great time to check out the National Sleep Foundation website here to learn more ways to improve your sleep.
Sleep Well!
Sources:
Miller MA, Cappuccio FP. A systematic review of COVID-19 and obstructive sleep apnoea. Sleep Med Rev. 2020;55:101382. doi:10.1016/j.smrv.2020.101382
Kryger, Principles and Practice of Sleep Medicine, ed 6.
The National Sleep Foundation
Zhou Y, Hou Y, Shen J, Mehra R, Kallianpur A, Culver DA, Gack MU, Farha S, Zein J, Comhair S, Fiocchi C, Stappenbeck T, Chan T, Eng C, Jung JU, Jehi L, Erzurum S, Cheng F. A network medicine approach to investigation and population-based validation of disease manifestations and drug repurposing for COVID-19. PLoS Biol. 2020 Nov 6;18(11):e3000970. doi: 10.1371/journal.pbio.3000970. PMID: 33156843; PMCID: PMC7728249.
Lynn Keenan, MD, FAASM
About the Author: Lynn Keenan, MD, FAASM is board certified in Sleep Medicine and Internal Medicine and provides services at University Sleep and Pulmonary Associates. Dr. Keenan holds a faculty appointment with University of California, San Francisco in the UCSF Fresno Department of Internal Medicine.
To learn more about University Sleep and Pulmonary Associates, please click here.