Fear is defined as an unpleasant emotion caused by the belief that someone or something is dangerous, likely to cause pain, or a threat. This year we have all kinds of reasons to create this emotional response within our bodies without thinking twice about it. For many, Covid 19 has spurred more fear than we know what do with. But what actually happens to your body when these fearful thoughts are unleashed within the body?
There are several physiological changes that occur when experiencing fear. These processes are most commonly referred to as the fight-or-flight response. These changes within your body are designed to prepare you to either fight or run. Your breathing rate increases, heart rate follows suit, peripheral blood vessels (in the skin, for instance) constrict, central blood vessels around vital organs dilate to flood them with oxygen and nutrients, and muscles are pumped with blood, ready to react.
This process of fight-or-flight all begins within the amygdala, a bundled group of neurons within the brain that forms part of the limbic system, a key player in the processing of all types of emotions, including fear. The amygdala is able to trigger activity in the hypothalamus activating the pituitary gland. This is where the nervous system meets the endocrine system (LINK previous blog post) the center for our hormones. The pituitary gland secretes adrenocorticotropic (ACTH) hormone into the blood. At this time, the sympathetic nervous system — a division of the nervous system responsible for the fight-or-flight response — gives the adrenal gland a nudge, encouraging it to squirt a dose of epinephrine into the bloodstream. It’s at this point that you may feel like you are about to “loose your s#%t!”
Your body will release cortisol alongside the adrenal in response to ACTH. This is when you experience the rise in blood pressure, blood sugar, and white blood cells. The cortisol turns fatty acids into energy, ready for your muscles to be put to use. The epinephrine and norepinephrine hormones prepare your muscles for violent action, while also boosting activity in your heart and lungs. This reduces activity in the stomach and intestines, giving validity to the feeling of “butterflies” in your stomach. All of these responses are necessary when in harms way, but what research is only recently started to uncover is how this stress response has become chronic to many of us, and how this impacts our physical health, specifically our immunity.
The immune system is a collection of billions of cells that travel through the bloodstream. They move in and out of tissues and organs, defending the body against foreign bodies (antigens), such as bacteria, viruses and cancerous cells. The main types of immune cells are white blood cells. There are two types of white blood cells – lymphocytes and phagocytes. When you become stressed, hormones such as corticosteroid are released, and decrease your body’s lymphocytes — the white blood cells that help you to fight off infection. The lower your lymphocyte level, the more at risk you are for viruses, including the common cold and cold sores. Stress can also have an indirect effect on the immune system as a person may use unhealthy behavioral coping strategies to reduce their stress, such as drinking and smoking. Research has found a direct link between chronic stress, and headaches,. infectious illness like the flu, cardiovascular disease, diabetes, asthma, gastric ulcers, and fibromyalgia.
Emerging evidence can now trace the pathways of the mind-body interaction. When looking at lonely individuals, they tend to have more psychological stress or experience it more intensely, and in turn tamps down their immunity. It's also no surprise that depression hurts immunity. At the same time, depression may both reflect a lack of social support and/or cause someone to withdraw from social ties. Both can be stressful and hurt the body's ability to fight infection. All of these findings extend what we know about how stress management and interpersonal relationships can benefit day-to-day health, everything from helping us combat the common cold to supporting a speedy healing process after surgery.
A 2002 study out of John Hopkins School of Medicine reported that even chronic, sub-clinical mild depression may suppress an older person's immune system. Participants in the study were in their early 70s and caring for someone with Alzheimer's disease. Those with chronic mild depression had weaker lymphocyte-T cell responses to two mitogens, which model how the body responds to viruses and bacteria. The immune response was down even 18 months later, and immunity declined with age. In line with the 2004 meta-analysis, it appeared that the key immune factor was duration of depression, not the severity. And in the case of the older caregivers, their depression and age meant a double-whammy for immunity. Intuitively, all of this research makes sense when reflecting on early developmental relationships. The first human connections we had as a newborn were through the touch of another human. One could argue it to be the foundation of physical and social connection from start to end.
Put simply, your mind has a LOT more influence on your immune system than you probably know or perhaps want to acknowledge. To own that you have this much control over your health first emotionally, and then physically requires a willingness to take full responsibility. When you become aware of these impacts, you create new habits to address these stress responses before they do too much harm, and could very well be the thing that completely transforms your daily life. For me ways to better address your immunity, here are 5 Proven Ways to Concur Stress and Boost Up Immunity.