Immune System And Lack Of Sleep

Overview

In recent years, the importance of sleep has been highlighted very often in our workplaces and the community. Sleep is deemed the best meditation. It is an integral and essential part of maintaining our mental and physical health. It helps in optimal functioning of the body and mind, helps in tissue repair, and, most importantly improves health; a sound sleep also boosts our immune system functioning.¹ Sound sleep can build a strong immune defence system and provide innate and adaptive immunity. On the other hand, sleep deprivation and not having sound and regular sleep can severely impact the normal and healthy functioning of our body, especially the immune system.² 

About The Immune System 

Before further delving into the effects of the immune system on sleep and vice versa, let us take a moment and get to know the immune system. Our body is continuously exposed to infectious particles from our daily activities, starting from food to the keyboard of our laptop, or the door lock. Pathogens are everywhere, and we cannot hide from them. These organisms infect and inhabit our bodies and alter normal functioning. To protect ourselves from these pathogens, our body has an inbuilt immune system which is an interactive network of cells, lymphoid organs, and humoral and cytokine factors. 

The immune system has two parts: innate immunity (general) and adaptive immunity (specialised). Innate immunity includes physical, chemical, and microbiological barriers. It also includes elements such as monocytes, macrophages (which kill microorganisms), neutrophils ( patrol to check the signs of microbial infection), and cytokines (signalling molecules). Innate immunity is considered necessary due to its immediate action toward the invading microorganisms. The response is fast but comes with a disadvantage; their lack of specificity damages the host cells.

On the other hand, we have adaptive immunity. Adaptive immunity is more specific, but it takes several days or weeks to develop an adaptive response. Adaptive immunity comes with memory cells. As the name indicates, they remember the pathogen in case it re-enters for the body. It will be recognised immediately and produce a faster, more rapid adaptive response. Adaptive immunity consists of B lymphocytes, or B-cells, which produce antibodies and T lymphocytes, or T-cells, which recognise antigens and stimulate B lymphocytes to produce antibodies and kill cells.³ 

We have briefly discussed the parts of the immune system and how they work. Now, we are able to discuss the advantages of the immune system.  

1. One of the immune system's primary and essential functions is protecting against the harmful microbes in our surroundings. It recognises foreign invaders to produce a biological response to fight them off.
2.  The immune response can be in the form of macrophages killing the microbes by phagocytosis, in which the microbe is engulfed in the cell and undergoes breakdown in subsequent processes, or in the form of antibodies produced by B-cells 
3. It also functions to identify harmful substances that have entered the body from our environment, and their subsequent neutralisation is also the function of the immune cells⁴
4. The immune system also functions to fight disease-causing changes in the body, such as cancer cells (cancer cells divide continuously and uncontrollably in the body, and they also infiltrate other parts of the body)⁴ 

About Lack of Sleep

Before discussing the lack of sleep and its consequences on human health, we should be clear about sleep. A healthy human’s life is based on eating, exercising, and sleeping regularly. If any of these fall short, the chances of living a healthy life will be decreased. As per the research of the National Sleep Foundation, an average of seven hours of sleep is the preliminary step of living a healthy life and is considered a good amount of sleep. Suppose we put our health in danger for any reason, such as office stress, anxiety issues, or other problems where we get insufficient sleep at night. There are various causes for a lack of sleep, such as sleep disorders, lifestyle choices, and stress due to workload.⁵ Sleep deprivation can cause various health hazards to our health such as:⁶ 

1. high blood pressure, stroke, heart failure, or heart attack
2. Insufficient sleep can sway our physical appearance too. Dark circles around our eyes, loose posture, lack of attention, and daytime sleepiness can occur here
3. Sleep deprivation can cause a surge in cortisol levels which in turn causes collagen breakdown. Collagen is a protein in our skin, connective tissues, bone, and cartilage. Collagen also keeps our skin smooth. In short, poor sleep causes wrinkles on our faces

Link between the immune system and lack of sleep

As discussed earlier, sleep has an important influence on our body's systems. When we discuss these systems, the immune system also comes into this. The role of cytokines can explain the link between sleep and the immune system. Cytokines are signalling molecules secreted by T-cells. Tumour Necrosis Factor-alpha (TNF-ɑ) and interleukin-6 (IL-6) are related to sleep and are extensively studied. The increased levels of these cytokines cause an increase in NREM sleep.⁷ NREM sleep is when our heartbeats, eye movements, and breathing activity begin to slow down.⁸ 

Effects of lack of sleep on the immune system and vice versa

Sleep and circadian rhythm are potent regulators of immunological processes. This influence is firmly based on the bidirectional communication between the central nervous and immune systems. Here, the immune system is mediated by signalling molecules such as cytokines and neurotransmitters and innervations by the autonomic nervous system. Poor sleep decreased the levels of antibodies produced. 

Summary

In this era of advancements and rapid innovations, getting sound sleep has become a significant problem for many people. Sleep is considered the best form of meditation and has become integral to human mental and physical health. Healthy sleep can enhance our immune response, and insufficient sleep can alter it. In our daily life, we are exposed to many pathogens and microbes that are persistent in invading our bodies. To stop these harmful and infection-causing microbes, our body has an immune system. It is an interactive network of lymphoid organs, cells, and molecules that consistently fights and destroys these invading microorganisms. Our immune system can be categorised into 2 types based on speed and selectivity/specificity: adaptive immunity and innate immunity. Innate immunity shows a rapid host defence and is not selective. Adaptive immunity is the opposite of that and has a slow response, but it lasts for a lifetime due to the presence of memory cells. Immune system functions in identifying and destroying harmful substances. It is also involved in killing cancer cells. Many factors cause sleep loss, such as anxiety issues, workload stress, and sleep disorders. Sleep loss can impact our body functions and appearance by causing wrinkles and dark under-eye circles. Sleep deprivation can also impair and alter the normal and beneficial functioning of the immune cells. In the end, if we want a healthy lifestyle with solid immune defences, we need to sleep well regularly.