The ANS and Chemical Messengers

One of the most powerful chemical messengers of the autonomic nervous system (ANS) is adrenaline, also known in scientific communities as epinephrine. When called upon, this formidable chemical courses throughout the body via the bloodstream.

“The energy of the crowd is insane. Twenty thousand people. It’s the biggest jolt of adrenaline. It’s very hard to explain. You know the old story about the woman lifting the car off her kid? It’s in that realm. You can actually hurt yourself and not know it.” 

Tom Petty, Rock Star 

Esquire Magazine Interview 

June 29, 2006 

Adrenaline is derived from noradrenaline, which is also known as norepinephrine. Adrenaline is secreted in small increments every day, even during the most basic tasks, such as getting out of bed in the morning. During highly stressful moments, adrenaline surges through our bloodstream and enables us to respond to acute stress or danger. 

The term “fight or flight response” was first described by Walter B. Cannon in 1915 at Harvard University after observing the natural physical changes that occur, including a surge of adrenaline, in response to life-threatening stress. 

The ANS depends on the proper balance of adrenaline in response to both the normal stress of daily living and to the high stress of acute situations. Adrenaline has many physical effects on the body. 

Adrenaline can: 

  • Increase blood pressure 
  • Increase heart rate 
  • Increase blood flow to the muscles of the body 
  • Expand airways in the lungs 
  • Enlarge pupils of the eyes for better sight 
  • Decrease blood flow to the gut 
  • Cause a metabolic change to maximize blood glucose/energy levels throughout the body 
Young woman running

Mom Lifts Car to Save Son

Mrs. Maxwell Rogers, a resident of Tampa, Florida, earned a Guinness World record by lifting one end of a station wagon after the car fell off a bumper jack and onto her teenage son on April 24, 1960. During the amazing car lift, fueled by an unusual burst of adrenaline, Mrs. Rogers, who weighed 123 lbs., lifted an estimated 1000 lbs. and sustained fractures of several vertebrae.1 

This is one of many reports of people using supernatural strength in life-threatening situations. Although Mrs. Rogers was severely injured, it is likely she did not sense pain at the time because the adrenaline that flooded her body had the ability to block pain receptors that normally protect us from injury. 

Addicted to Adrenaline?

Although adrenaline is a natural chemical that is essential for functioning, many people are drawn to activities that give them an extra boost of this neurotransmitter. Exercise is great activity that boosts a healthy increase of both adrenaline and norepinephrine in the blood- stream. But what happens when we have repeated surges in adrenaline when there is no real danger or stress? And why is it that many people today who live high stress lives also choose recreational activities that cause additional adrenaline surges? 

Movie producers seem to know this addiction well, as a vast majority of films are action-packed thrillers that are expected to give us an adrenaline rush even though we’re just sitting and watching. On YouTube you can watch a back-to-back showing of trailers from the top 20 movies that fuel our adrenaline, from The Dark Knight to The Fast and the Furious. 

Stressed young businesswoman at office desk with notepad

When our Lives are Filled with Chronic Stress

According to the Mayo Clinic, long-term chronic stress may put your health at risk. “The body’s stress-response system is usually self-limiting. Once a perceived threat has passed, hormone levels return to normal. As adrenaline and cortisol levels drop, your heart rate and blood pressure return to baseline levels, and other systems resume their regular activities. But when stressors are always present and you constantly feel under attack, that fight-or-flight reaction stays turned on. 

The long-term activation of the stress-response system—and the subsequent overexposure to cortisol and other stress hormones—can disrupt almost all your body’s processes. This puts you at increased risk of numerous health problems.”2 

Since adrenaline is the most powerful chemical messenger of the ANS, it may be helpful to think of it as a double-edged sword: Essential for healthy living; but, capable of causing harm when overused. In dysautonomias, acute or chronic stress is a common trigger for on- set or relapse of symptoms. 



1 Smith, Jack. “Guinness Gives Records.” 

2 Mayo Clinic Staff. Patient Care & Health Information; Healthy Lifestyle Stress Management., July, 2015. 

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