Let’s start with the basics: the sympathetic and parasympathetic nervous systems. Both are part of the autonomic nervous system, a regulatory center that influences organs, vessels, glands, genitals, and digestive system, driving the survival reactive and regulatory involuntary functions of the body.
The parasympathetic system manages metabolism, reproductive health, sleep and energy cycles, body temperature, and fluid regulation and is often referred to as the “rest and digest” state while the sympathetic nervous system is the reactive survival response is often referred to as “fight or flight.”
When the body is under stress, it favors the sympathetic nervous system. This drives the activity of the hypothalamic-pituitary-adrenal axis (HPA axis), stimulating the adrenal glands to release cortisol and stress-responding neurotransmitters.
In a balanced body, cortisol serves to provide negative feedback to the HPA-axis, telling it the stress-responding chemical has been released and the body can go back to its regulatory, parasympathetic state. However, in a chronic stress state, the body does not shift from sympathetic mode back into parasympathetic, instead continuing to fire stress response chemicals while suppressing the regulatory function.
Unfortunately, in our modern lifestyle, stressors are plentiful and constant. This is where we start to see the influence of chronic stress on hormone balance.