Part one of our entry on stress and how it effects your immune system
Your Immune System
Your immune system is a complex and highly organized network of tissues, glands, cells and chemical messengers. Continually on guard to protect your body against disease, it identifies, isolates and eliminates pathogens (viruses, bacteria, parasites, and fungi), dead and cancerous cells, and other substances it recognizes as foreign. These various immune activities are coordinated through an interactive communication network that also involves your brain and stress response system. Each component in this vast network contributes to the regulation of immune function.
Immunity and the Stress Response
When you experience any type of physical or emotional stress, your body’s physiological reaction is the same as that of early humans: an immediate, short-term response programmed to help you physically deal with the stressor. Your brain signals your adrenal glands to secrete hormones, such as adrenaline and cortisol, that prepare your body for action. These hormones cause the “fight or flight” response, in which every system in the body becomes primed to do one of two things: fight the stressor or escape. The stress response increases heart rate and blood pressure to rush blood and nutrients to muscles, mobilizes sugar into the bloodstream where it can be used for energy, and focuses attention. You may have noticed these physiological changes after experiencing something like a near miss in traffic – your heart pounds, your breathing increases and your muscles tense. However, there are other important changes triggered by stress hormones that are not so readily apparent. One of the most important of these is the alteration in immune function. Almost every immune cell in the body has receptor sites for either cortisol, adrenaline, or both. The acute fight or flight response set off by adrenaline can be pro-inflammatory and temporarily boosts certain aspects of innate, front-line immunity that help reduce the chance of infection from an injury sustained in the fight or flight. The accompanying elevated cortisol suppresses the deeper, adaptive aspects of immunity that protect you over the long term from disease. If you are facing a lion, your body will shift energy resources from less immediate threats (like fighting cancer or a cold) to help you survive the critical danger in front of you. When stress is chronic or prolonged, both the increase in inflammation and the decrease in overall immune function can begin to adversely affect your health.