What is stress? It is often perceived as an event that causes worry or anxiety: a work or school project, family difficulties, major life events and other concerns. But stress can be defined as anything that places a burden on the body, mind or spirit. So in today’s modern world no one is free from its grasp. We are constantly bombarded by not only emotional and mental stressors, but physical stressors as well, such as pollution, toxins, pathogens and less than optimal lifestyle choices.
During an acute stressor, such as a near accident, our bodies respond accordingly: our pupils dilate, our breathing increases, and our sense of time slows down. But when the event passes, we return to a balanced state, homeostasis; critical not only to our survival, but to our overall wellness. Typically our stress response functions as it should. But our daily lives don’t provide us with a filter for acute stressors only; we are often in a state of chronic stress. The stress we experience is chronic in part due to the nature of our lives today and environment in which we live. But it is also due to the capacity we have of being able to think about life events, past and future. And it turns out that this causes the same physiological responses that the actual stressors do! We can worry about a relationship or upcoming conflict without actually begin in that conflict and we will respond: our heart rate will increase, as will our breathing. Unfortunately because of the body’s need for homeostasis and the ability to adapt, many of us become used to the “stress” and stop noticing it on a conscious level until our body starts talking to us through unpleasant symptoms.
Why is chronic stress so hard on the body? To answer that, let’s look at the key system involved in our stress response: the autonomic nervous system (ANS). The ANS is composed of two subsystems—the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system is in charge of what we typically refer to as the “fight or flight” response. When we experience a stressor, or think about one, it gets us physiologically ready to respond. Our body, through a complex process, kicks our sympathetic nervous system into high gear, and releases adrenaline, cortisol, epinephrine and norepinephrine to start the process. Our heart rate and blood pressure increase, glucose levels rise to meet energy demands, and veins constrict to increase the amount of blood going to major muscles while smooth muscles relax to get more oxygen into to our lungs and pupils dilate to let more light in.
When the stressor has passed, we want to return to balance—homeostasis, and that is what the parasympathetic nervous system is for. The parasympathetic nervous system, also known as the “rest and digest” response, brings us back down: our heart rate slows, as does our breathing; we begin to digest food again, and the functions that were deemed “non-essential” in the moment of stress, from which energy is diverted to systems necessary for the “emergency”, can resume. Both systems work synergistically with one another, neither should be dominant. But the world we live in today creates a breeding ground for sympathetic nervous system dominance.
Why is it that prolonged stress or sympathetic nervous system dominance is so hard on the body? The systems that experience increased function during nervous system dominance can lead to: cardiovascular problems, blood sugar imbalances, weight gain, muscle pain and tension, suboptimal digestion, low libido, and suppressed immune function, just to name a few. Stress and poor health fuel each other, creating a vicious cycle. It is important to return to a homeostatic state where the ANS is in balance for optimal function of all of our systems.