Writer: Priya Desai
Editor: Isabella Io
Stress is an unavoidable aspect of life and can profoundly impact an individual's mental and physical health. Chronic stress significantly weakens the immune system, making the body more susceptible to illnesses and infections. Understanding the relationship between stress and the immune system is extremely important for developing strategies to reduce its negative effects on health.
What is Stress?
Stress is a biological response to a perceived threat. It’s caused by chemicals and hormones surging throughout your body. It can help you respond to a particular problem, but too much stress can harm your health. Stress triggers your fight-or-flight response to fight the stressor or run away from it. Typically, after the reaction occurs and the trigger is gone, your body should relax. Too much constant stress can have negative effects. [8]
What is the Immune System?
The immune system is a large network of organs, white blood cells, proteins and chemicals. These parts all work together to keep you healthy. It helps your body heal from infections and injuries, as well as protect you from germs. [5] White blood cells, which are also known as leukocytes, are responsible for protecting your body from infection. White blood cells circulate in your blood and help with fighting off injuries or illness. White blood cells are formed in the soft tissue inside of your bones (bone marrow). [10] Inflammation is the immune system's initial reaction to infection or irritation, and it can also occur due to tissue damage from abnormal or uncontrolled cell growth. This response involves various immune cells and their secreted mediators and products. [9]
The Link Between Stress and Immune Function
When the body perceives a stressful situation, it triggers the "fight-or-flight" response, releasing stress hormones such as cortisol and adrenaline. While this response is beneficial for short-term threats, chronic activation of the “fight-or-flight” response can be detrimental. [6] Prolonged exposure to stress hormones can suppress the immune system's functionality, reducing its ability to fight off antigens and increasing vulnerability to infections and diseases.
Studies have shown that chronic stress can decrease the production of white blood cells, which are essential for fighting infections. Additionally, stress can reduce the effectiveness of the body's inflammatory response, which is crucial for healing and fighting infections. [2] This weakened immune response is a key factor in the development of various health issues, including autoimmune diseases, heart disease, and increased vulnerability to viral infections like influenza. [4]
Psychological Stress and Immune Dysregulation
Research shows that individuals experiencing elevated levels of negative emotions or psychological stress, such as anxiety or depression, is linked to immune dysregulation - showing in higher levels of inflammation and lower immune response. This dysregulation can be particularly harmful as it may lead to chronic inflammation, which is associated with various diseases such as arthritis, cardiovascular diseases, and certain cancers. [1]
Moreover, stress can exacerbate existing health conditions. For example, individuals with autoimmune diseases may experience flare-ups or worsened symptoms during periods of high stress. Flare-ups are when the symptoms of a disease or condition suddenly get worse. This relationship shows the importance of managing stress to maintain overall health. [3]
Behavioral Responses to Stress and Health
Stress can also influence health indirectly through behavioral changes. Individuals under stress are more likely to engage in unhealthy behaviors such as smoking, excessive alcohol consumption, poor diet, and lack of physical activity. These behaviors can further weaken the immune system and contribute to the development of chronic diseases.
Additionally, stress can affect sleep patterns, leading to insufficient or poor-quality sleep. Adequate sleep is vital for a healthy immune system, and chronic sleep deprivation can impair immune function, making the body more susceptible to illnesses. [8]
Implications for Mental Health
The interactions between stress and mental health is complex and two- way. Chronic stress can lead to mental health disorders such as anxiety and depression, which can further weaken the immune system. [7] Furthermore, mental health disorders can increase stress levels, creating a continuous cycle that is challenging to break. [1]
Addressing stress and its impact on mental health requires a multifaceted approach. Therapeutic interventions such as cognitive-behavioral therapy (CBT), mindfulness, and stress management techniques can be effective in reducing stress and improving mental health. Regular physical activity, a healthy diet, and adequate sleep are crucial for managing stress and supporting the immune system. Quality sleep allows the brain to process emotions and recover from daily stressors. Altogether, these habits create a balanced approach that supports overall well-being and mental health.
Conclusion
Understanding the intricate relationship between stress and the immune system highlights the importance of managing stress for overall health. Chronic stress not only weakens the immune system, making the body more susceptible to diseases, but also increases the severity of mental health issues. By adopting healthy lifestyle habits, engaging in regular stress management practices, and seeking professional help when needed, individuals can decrease the negative impacts of stress on their immune system and overall well-being.
Sources & Credits
[1] Brosschot, J. F., Gerin, W., & Thayer, J. F. "The perseverative cognition hypothesis: A review of worry, prolonged stress-related physiological activation, and health." Psychosomatic Medicine, vol. 68, no. 2, 2006, pp. 211-224, https://pubmed.ncbi.nlm.nih.gov/16439263/
[2] Dhabhar, Firdaus S. "Effects of stress on immune function: the good, the bad, and the beautiful." Immunologic Research, vol. 58, no. 2-3, 2014, pp. 193-210,
[3] Cohen, Sheldon, Janicki-Deverts, Denise, & Miller, Gregory E. "Psychological stress and disease." JAMA, vol. 298, no. 14, 2007, pp. 1685-1687,
[4] "Stress and the Immune System." SSC Psychology, 28 Nov. 2012,
[5] “Immune System Function, Conditions & Disorders." Cleveland Clinic, 20 Oct. 2023,
[6] "Understanding the Stress Response." Harvard Health, 22 Oct. 2020, https://www.health.harvard.edu/staying-healthy/understanding-the-stress-response#:~:text=After%20the%20amygdala%20sends%20a,as%20adrenaline)%20into%20the%20bloodstream
[7] "Stress and Illness." Introduction to Psychology, Lumen Learning,
[8] “The Effects of Stress on Your Body." Healthline, 27 Apr. 2023 https://www.healthline.com/health/stress/effects-on-body
[9] Vaknin, Ilan, and Michal Baniyash. "Inflammatory Response and Immunity." Encyclopedia of Cancer, edited by Manfred Schwab, Springer, Berlin, Heidelberg, 2011, pp. 1859-1864.
[10] “White Blood Cells.” Cleveland Clinic, Cleveland Clinic, 23 July 2021.
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