Our fight-or-flight response is our body's sympathetic nervous system reacting to a stressful event. Our body produces larger quantities of the chemicals cortisol, adrenaline and noradrenaline, which trigger a higher heart rate, heightened muscle preparedness, sweating, and alertness - all these factors help us protect ourselves in a dangerous or challenging situation.
Non-essential body functions slow down, such as our digestive and immune systems when we are in fight-or flight response mode. All resources can then be concentrated on rapid breathing, blood flow, alertness and muscle use.
When we are stressed the following happens