It triggers a cascade of physiological responses that enables you to instantly respond to what is causing your stress, by freeing up tons of energy and directing it to areas in your body and brain that need it most. This automated nearly-instantaneous biochemical and physiological response is as old as human kind and it is highly functional in life-threatening situations, or any situation that asks for an instant physical reaction to cope with the challenge (stressor) at hand. Our stress response is so fast, that it’s fully operational even before our brain’s sensory centers have had a chance to fully grasp what is going on. This is why you are able to jump out of the path of an oncoming car even before you think about what they are doing.
Cortisol is the primary hormone responsible for the stress response. It effects virtually your entire body and impacts several homeostatic mechanisms. While cortisol’s primary targets are metabolic, it also affects your immune response and your memory. It carefully regulates the level of glucose circulating through the bloodstream. This enables your body to maintain steady supplies of blood sugar and helps you to stay revved up and on high alert. Allowing you to cope with prolonged stress; continue your fight or flight.