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Your autonomic nervous system takes care of things without your conscious involvement, all day, every day. While you're awake and while you're asleep.
Breathing, digesting your food, blood flow, sweating, just to name a few functions, are the territory of the autonomic nervous system.
There are two branches, the parasympathetic nervous system and the sympathetic nervous system. These two systems do not operate simultaneously. When one is active, the other is not.
The parasympathetic nervous system is in control when you are relaxed or at rest. If you are taken by surprise by an emergency or a stressful situation, the sympathetic nervous system takes over like the Incredible Hulk and roars into action.
This "fight or flight" response makes your heart beat faster, sending blood at a faster than normal rate throughout the body. Digestion slows, so that more energy is available for the perceived challenge.
Your adrenal glands release the stress hormone adrenaline, also called epinephrine, which activates your muscles with extra oxygen, dilates your pupils and make your response to the situation the biggest, best and fastest it can be.
Short-term, this arrangement works very well. It keeps us safe and alive. And when the parasympathetic nervous system takes over after the crisis, ideally the body has an opportunity to regain its balance and carry on.
But sometimes the sympathetic nervous system stays active for extended periods of time. Perhaps you've lost your job, or lost a loved one. Perhaps you are being bullied at school or at work.
Maybe you have financial problems that leave you feeling vulnerable and afraid. Feeling in danger and at risk is a clarion call to the sympathetic nervous system.
When the sympathetic nervous system is in charge for too long, the adrenals may release cortisol instead of adrenaline. Over time, a chronic overuse of cortisol can cause harm to our brains and our bodies.
This is chronic stress. This is a road to poor health.
The hypothalamus is the part of your brain that kicks off the stress response. Non-essential body systems are bumped down the priority list.