In our fast-paced, modern world, stress has become an inevitable part of life for essentially everybody. Whether it’s due to work pressures, personal expectations, or socioeconomic challenges, the effects of stress can permeate every aspect of our well-being. One critical aspect that often takes a toll is our immune system. It’s important to understand the intricate relationship between stress and the immune system, as well as how chronic stress can compromise our body’s top defense mechanisms.
Stress is the body’s natural response to perceived threats or challenges, which can come from both an internal or an external stimulus. When the body encounters these stressors, we produce a stress response; an immediate stress response and a lower-grade slow response as a result of activating the HPA axis. For some of these stressors, the body activates a “fight or flight” response, releasing hormones such as epinephrine or norepinephrine from the adrenal medulla. This is a quick action response to stress that quickly increases heart rate, tightens blood vessels, increases blood pressure, and opens up the lungs. Epinephrine also increases blood flow to muscles and increases the amount of sugar/nutrients in the blood. These actions of epinephrine are important in that it allows the body to engage in that fight or flight response quickly (1). For the slow stress response, we also release cortisol, a hormone also released from the adrenal glands, but from the adrenal cortex. Cortisol, considered a “glucocorticoid”, helps optimize the action of epinephrine & to liberate blood sugar from storage throughout the body as well as produce new sugar for the system to use in moments of stress. While these responses are essential for survival in acute situations, prolonged or chronic stress can lead to a cascade of negative effects on various physiological systems, including the immune system.
The immune system can be divided into two categories, the innate immune system and the adaptive immune system. This defense system is a complex network of cells, tissues, and organs working together to defend the body against harmful invaders, such as viruses, bacteria, and other pathogens. This system also works to remember previous infections, catch early infections before they establish a foothold, create local and body-wide inflammation, and attack compromised cells (for a refresher of the actions of the immune system and what we can look at with basic blood work, check out the webinar recorded by Dr. Forsberg & Dr. Woods back in October 2021, linked below). While the actions of the immune system work intricately together, a delicate balance is necessary for optimal immune function, and disruptions to this balance can have profound consequences.
Chronic stress can alter the balance of immune cells in the body. One way it does this is by decreasing the action of the immune system (a term called immunosuppression) in order to decrease inflammation. For instance, it may lead to a decrease in the number of T lymphocytes, which play a crucial role in orchestrating the immune response. Cortisol can also reduce the movement of neutrophils (some potent bacteria fighters) & prevent B-cells from producing antibodies (5). This is why you will often see cortisol (or analogs) being used in states of chronic inflammation; think: prednisone, cortisone injections, etc. For a short term and under conditions of normal stress, this can be really helpful and protective for the body. But when stress is chronic and cortisol output seems relentless, this compromised immune function can leave individuals vulnerable to infections including recurrent or reactivated viral infections, increased autoimmune susceptibility, and to cancer.
Luckily there are things that can help mitigate stress and support the immune system:
Stress management: Adopting stress management techniques, such as meditation, deep breathing exercises, and mindfulness, can help mitigate the physiological effects of stress. These practices have been shown to reduce cortisol levels and promote overall well-being. (2) 2.
Movement: Physical activity has been linked to improved immune function and reduced stress. Regular exercise can enhance the production of endorphins, the body’s natural mood elevators, and contribute to a more resilient immune system. (3) 3.
Foundations of health: A balanced diet (4), sufficient sleep, and maintaining a healthy lifestyle contribute to overall well-being. These factors support immune function and provide the body with the resources it needs to cope with stress.
Recognizing the intricate connection between stress and the immune system is essential for promoting holistic wellness. By adopting stress management strategies and making lifestyle choices that support a healthy and robust immune function, we can strive to strike a balance in our lives, enhance our overall well-being and be resilient in the face of all of life’s (internal & external) stressors.
Webinar link:
(1): Epinephrine – statpearls – NCBI bookshelf. (n.d.).
(2): Koncz, Adam, et al. “Meditation Interventions Efficiently Reduce Cortisol Levels of At-Risk Samples: A Meta-Analysis.” Taylor & Francis Online, Health Psychology Review, 7 July 2020,
(3): De Nys, Len, et al.. “The Effects of Physical Activity on Cortisol and Sleep: A Systematic Review and Meta-Analysis.” Psychoneuroendocrinology, Pergamon, 24 June 2022,
(4): Weyh C, Krüger K, Strasser B. Physical Activity and Diet Shape the Immune System during Aging. Nutrients. 2020; 12(3):622.
(5) : Thau L, Gandhi J, Sharma S. Physiology, Cortisol. In: StatPearls. StatPearls Publishing, Treasure Island (FL); 2022. PMID: 30855827.