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Autonomic Nervous System - Parasympathetic Reflex/Cortisol Hormone

Get out your anatomy and physiology books! (You don’t have to, but we are

going to review the physiological implications of STRESS -Ugh, don’t you just hate

that word? Alright, let’s get started; it’s more complicated than you’d [like to]


Imagine, it’s been an awful week: It’s Monday. You’re not feeling well. Didn’t

have breakfast. In a traffic jam. Late for work. Your boss has called; twice. The sirens

of an ambulance? Gridlock. Where to pullover? Phone rings: you need to pick up

your sick child. POW! Flat tire… Can you feel the stress mounting? Muscles tense,

heart rate increases, breath tightens. This is the work of your autonomic nervous


This branch of your nervous system helps to regulate internal organs and

involuntary movement in the body. It is divided into two branches: the

parasympathetic nervous system: controls the relaxation response, and the

sympathetic nervous system: controls the fight or flight response. These branches

operate complementary to one another attempting to maintain balance, keeping the

body in metabolic equilibrium, or better known as homeostasis. Usually when a

stressful stimulus occurs, the body moves through the negative feedback loop and

the two systems are able to bring balance to the body. However, with sustained

stress the sympathetic nervous system is always “on”, never allowing the body to

activate the parasympathetic nervous system, recover and relax. Exposure to

sustained stress and time with the sympathetic nervous system “on” can lead to

long-term health effects that prolong recovery time, or inflict irreparable damage

via hormone imbalance.

When an individual is faced with a stressor a complex hormonal reaction

occurs. First adrenaline is secreted. If the stressor(s) continue to be present cortisol

is secreted; this prepares the body for fight or flight and triggers a number of

internal reactions. Muscles are flooded with glucose, providing immediate energy

supply; insulin production is halted encouraging the prompt use of glucose and

preventing it form being stored; blood vessels narrow, heart rate increases,

increasing blood pressure and forcing the heart to work harder.

Here is the turning point:

-If the stressor(s) is/are addressed and resolved, the parasympathetic

nervous system will turn “on”, and hormone levels will return to normal and

optimal bodily functions will resume.

-If the stressor(s) is/are not addressed and resolved the secretion of the

stress hormone, cortisol, continues. Overtime cortisol adversely affects brain

functioning, as it interferes with neurotransmitters. Since the “lines are

down” this results in decreased learning and decreased ability to create new

memories or recall old memories. The continued presence of cortisol

interferes can lead to GI dysfunction, increased weight gain, chronic disease

risk, and inflammation and decreased immunity. An increase in sleep

disorders is also associated with elevated activity in the sympathetic nervous

system, which only perpetuates the cycle and robs the body of the repair and

healing that takes place during REM sleep cycles.

Stress is unavoidable, especially in our fast paced, ever-changing world. What

is important is not trying to avoid stress, but to examine how we react to it. How do

we avoid spurring ourselves into self-perpetuating stress cycles?

-Breath: The mechanical action of taking a big, deep breath will allow for

increased oxygen to the brain and muscles. This will allow clearer thinking,

and the muscles to relax. Also, a shift of focus away from the stressor to the

breath will take you, momentarily, out of any negative thought loops and may

allow for better perspective.

-Get out: Remove yourself, physically or mentally, from the stressor. Taking a

few moments to center may allow for time to clear your head, take a few

breaths and allow for a response rather than a reaction that may only

increase stress levels.


-Exercise: Whether you are running 10 miles or relaxing in a long-held yoga

pose, getting out of your head, remove you from the situation, get into your

body, increase your breath and burn off some extra (nervous?) energy.

-Massage: Massage helps to turn “off” the sympathetic nervous system and

turn “on” the parasympathetic nervous system. When the body is massaged

blood and lymph circulation is increased moving vital nutrients and oxygen

to through out the body to organs and muscles. Serotonin and endorphins

essential for healthy mental functioning and decreasing depression and

anxiety are secreted.

Stress affects everyone differently, and affects genders differently. To this I

encourage you to listen to yourself, you will know when too much is too much. I

hope understanding the silent affects of stress on your body encourages you to

reevaluate how you handle stress. No matter which tools you decide to employ, at

least you now have a few more.

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