Inflammation, Stress, Sleep & Your Immune System

Inflammation, Stress, Sleep & Your Immune System

When most of us think of inflammation, we envision swollen red areas on our skin that accompany things like bee stings and twisted ankles[1]. You might even think about the classic acronym for reducing inflammation after injury: rest, ice, compression, and elevation (RICE). Though it's difficult to imagine, when we're nursing a painful injury inflammation can be a very helpful way for our bodies to repair after injury. As long as inflammation isn't too intense and it doesn't last too long, there's nothing to be concerned about.

What’s Immunity Got to Do with It?

In addition to protecting us from injury, inflammation is a key tool for our immune cells to use when warding-off a threat from a pathogen (tiny germs that can make you sick)[2]. This process utilizes cell signaling proteins that regulate inflammation called cytokines to achieve a couple of functions[3]. For instance, when we're actively fighting-off pathogens, our immune systems activate cytokines to dilate (enlarge) blood vessels and call for more immune cells to come and help, which can cause systemic inflammation (meaning inflammation that affects your entire body, rather than a specific area or organ). In such cases, systemic inflammation is a helpful way for our bodies to direct an attack against pathogens. But it's not just illness that causes inflammation throughout our bodies.

Allergies, autoimmune diseases (caused when our bodies target our own cells, mistaking them for pathogens) and even many of the inflammation triggers I discuss in the next section can cause chronic (long-lasting) systemic inflammation.

It's important to understand the distinction between short-term and long-lasting inflammation to appreciate why long-term inflammation is so harmful. When inflammation occurs as a result of an infection, our bodies will clear that infection and then return to a baseline uninflamed state. This is called acute (short-term) inflammation. However, when inflammation is caused by a trigger like lifelong stress, our bodies struggle to return to baseline[4]. That's because prolonged high stress continually releases cortisol (an immune-suppressing adrenal hormone), which our immune systems respond to over long periods of time by amping-up the production of cytokines. Without a reduction in stress, inflammation will continue to occur.

Inflammation Triggers

Many of us are under intense stress, getting too little sleep, eating a processed diet low in essential nutrients, not exercising regularly or over-exercising (over-training), and coping with mental health struggles such as depression and anxiety. Tons of other triggers, such as smoking cigarettes, drinking alcohol, and living in an area with bad air quality all cause dangerous amounts of inflammation in our bodies[5].

Aside from directly limiting our ability to respond to pathogens, left unchecked, they also cause inflammation that can contribute to the development of chronic diseases such as diabetes, Alzheimer's disease, cancer, and cardiovascular disease.

Inflammatory Sleep

Take poor sleep quality, for example. People who get less sleep are more likely to catch a cold, but it turns out that these individuals also experience more systemic inflammation[6]. Though it's not proven exactly why reduced sleep causes inflammation, scientists believe that a lack of sleep triggers excess pro-inflammatory signals in our blood vessels. Individuals who sleep poorly have consistently higher levels of specific cytokines that are precursors to chronic disease, than those of us who sleep well. This is a major reason people who experience constant sleep debt (accumulative sleep loss) have a much higher incidence of heart disease.

A common theme in immunology (and science as a whole) is the positive feedback loop. Poor sleep quality contributes to inflammation, stress, negative mindset, and a lack of energy to make healthy decisions about diet and exercise. In turn, these factors all result in continued poor sleep quality, because we don't sleep well when we have high stress, especially in the absence of regular exercise. Inflammation is amplified by each factor, which increases the likelihood of developing chronic disease[7]. You can imagine how this feedback loop—where each factor increases the likelihood of the next occurring—could quickly get out of hand.

As we conclude our deep dive into the interconnectedness of inflammation, stress, sleep, and immunity, we underscore the necessity of balance and the pursuit of healthful habits in our lives. Our bodies may be truly remarkable machines, however they can easily be overworked and stressed by various triggers, and the resulting inflammation can significantly hamper our ability to combat disease.

5 Takeaways

  • Inflammation is not inherently bad - It's a natural response your immune system uses to protect and heal you. However, chronic or systemic inflammation is a well-known contributor of health problems over time.
  • Chronic stress = long-lasting inflammation - Continuous high stress can cause our bodies to be in a perpetual state of inflammation due to the sustained release of cortisol and excess production of cytokines.
  • Lifestyle habits significantly impact inflammation - Poor sleep, unhealthy diets, lack of regular exercise, and constant exposure to environmental pollutants are all triggers for potentially harmful inflammation.
  • Inflammation contributes to chronic diseases - Chronic inflammation can significantly increase the risk of conditions such as diabetes, Alzheimer's disease, cancer, and heart disease.
  • Feedback loop of poor health choices - Poor sleep quality, stress, unhealthy dietary habits, and lack of exercise not only cause inflammation individually, but they also feed into each other, making it harder to break the cycle and regain balance.

In summary, understanding the importance excess inflammation impacts our overall health, and how various lifestyle factors can trigger harmful, long-term inflammation, helps illuminate the road to better health. In order to experience optimal health, one must mitigate stress, enhance sleep quality, maintain a balanced diet, and engage in regular exercise. In doing so, we can ensure our immune systems function optimally, maintaining a healthy equilibrium of inflammation and thereby minimizing the risk of chronic disease. After all, the best offense is always a good defense.

References

 

[1] Schett, G., Neurath, M. F. (2018). Resolution of chronic inflammatory disease: universal and tissue-specific concepts. Nature Communications. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6197179/
[2] Immune response and inflammation: Medzhitov, R. (2008). Origin and physiological roles of inflammation. Nature. https://www.ncbi.nlm.nih.gov/pubmed/18650913
[3] Akdis, M., Aab, A., Altunbulakli, C., Azkur, K., et al. (2016). Interleukins (from IL-1 to IL-38), interferons, transforming growth factor β, and TNF-α: Receptors, functions, and roles in diseases. The Journal of Allergy and Clinical Immunology. https://www.ncbi.nlm.nih.gov/pubmed/27577879
[4] Cohen, S., Janicki-Deverts, D., Doyle, W. J., Miller, G. E., Frank, E., Rabin, B. S., Turner, R. B. (2012). Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk. Proceedings of the National Academy of Sciences. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3341031/
[5] Minihane, A. M., Vinoy, S., Russell, W. R., et al. (2015). Low-grade inflammation, diet composition and health: current research evidence and its translation. The British Journal of Nutrition. https://www.ncbi.nlm.nih.gov/pubmed/26228057
[6] Irwin, M. R., Olmstead, R., Carroll, J. E. (2016). Sleep Disturbance, Sleep Duration, and Inflammation: A Systematic Review and Meta-Analysis of Cohort Studies and Experimental Sleep Deprivation. Biological Psychiatry. https://www.ncbi.nlm.nih.gov/pubmed/26376074
[7] Wirtz, P. H., von Känel, R. (2017). Psychological Stress, Inflammation, and Coronary Heart Disease. Current Cardiology Reports. https://www.ncbi.nlm.nih.gov/pubmed/28861865

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