Sleep is a vital physiological process and is undoubtedly the most important eight hours of one’s day. It allows you to recharge the body and mind, enabling you to feel refreshed and energized for the new day. Without sleep, one may be susceptible to disease and the brain may not function optimally.
Sleep may be classified as either non-rapid eye movement sleep (NREMS) or rapid eye movement sleep (REMS).1 They are distinguished by electroencephalographic wave patterns, eye movement frequency and brain temperature. During a normal sleep, about 25% of sleep is comprised of REMS. However, this reduces to 10% in severe inflammatory states. Sleep regulation is associated with the circadian rhythm controlled by a pacemaker in the suprachiasmatic nucleus of the hypothalamus.1
Sleep deprivation paradigms are not standardized and are therefore difficult to compare findings amongst laboratories. Furthermore, sleep alone cannot be an isolated variable due to other physiological variables that change when awake. However, prolonged lack of sleep may cause hypothalamic failure. Acute sleep loss results in the release of stress hormones such as increased cortisol2, whilst during a normal sleep, stress hormones such as adrenaline and noradrenaline as well as prostaglandins decrease. This decrease in stress hormones allow for the stickiness of molecules called integrins3 to become stronger. Integrin stickiness allows for the contact of T cells to virus infected cells or cancer cells. This contact allows for the T- cells to kill the virus infected cell. In addition, acute stress may activate the immune system whilst chronic stress or infection damages the immune system.
Infections represent one form of systemic inflammation. Cancer, trauma and autoimmune diseases also fall under this category. Thus, sleep disorders are often associated with chronic fatigue syndrome and fibromyalgia due to systemic inflammation evident in these conditions. To measure the effects of sleep deprivation on the immune system, leukocytes and cytokines are studied. The degree thereof sleep results in different immune statuses. Plasma levels of Interleukin (IL)- 1β increases slightly during deprivation and decreases below baseline upon recovery. Interferon-γ levels fluctuate during deprivation but decrease significantly upon recovery1.
As seen above, sleep is important in maintaining our innate immune systems but in our waking lives we must continue to follow Covid-19 protocols. Remember to maintain social distancing of at least 1.5 metres and wear your mask correctly covering your nose and mouth. Furthermore, follow proper hygiene techniques by washing your hands with soap and clean water for at least 20 seconds or by using hand sanitizer with at least 70% alcohol content. Lastly, remember to dispose your mask safely and correctly and do not touch the front of your mask.
-Written by Nabeelah Jacobs
References:
1. Majde JA, Krueger J. Links between the innate immune system and sleep [Internet].2005 October 04 [cited 2021 May 21]116(6): 1188-1198. Available from: https://www.jacionline.org/article/S0091-6749(05)01719-7/fulltext. DOI: 10.1016/j.jaci.2005.08.005
2. Stanborough RJ. How does cortisol affect your sleep [Internet] 2020 July 10 [cited 2021 May 21] Available from: https://www.healthline.com/health/cortisol-and-sleep#disruption
3. Capitol Rehab of Arlington. The impact of sleep and stress resolution on your immune system: How T-cells stick it to the enemy [Internet]. 2020 April 15 [cited 2021 May 21] Available from: https://www.capitolrehabofarlington.com/2020/04/the-impact-of-sleep-and-stress-reduction-on-your-immune-system-how-t-cells-stick-it-to-the-enemy-2
