November 13th, 2009
01:46 PM ET

Fight or flight: The chemical motivator

ashleycarBy Ashley J. WennersHerron
CNN NY Medical News Intern

It was the last day of winter break. I was driving to a friend’s house to say goodbye before returning to New York for the spring semester. I was stopped at an intersection when the light turned green. I pushed down the gas and saw a flash of white. Next thing I knew, I was facing the wrong way, toward oncoming traffic and I could feel the January wind rushing in through the driver’s side window I had shattered with my head. My steering wheel was stuck and hitting the brakes did nothing. I hit another car head on and side-scrapped a third. I barreled up a hill, finally stopping just feet away from a row of gas pumps.
ashleycarpicMy airbags had deployed, filling the air with a foul smell and bits of grit. Disoriented and terrified, I thought the burning odor meant my car was on fire. I tore my seat belt open, which was no easy feat. In the impact, I slammed against the armrest, breaking it, which jammed the seat belt buckle. I got myself free, dove through the broken window (my door wouldn’t open), somersaulted to a standing position and ran away from the car I thought was going to blow up. When I reached what I perceived as safety, I collapsed. It felt as if I couldn’t move at all. During my escape, I couldn’t feel the pain, but as soon as I relaxed, I became aware of the extent of my injuries. My head felt as if it were leaking (a result of a concussion and a hairline skull fracture), my ribs were bruised, my leg was banged up and I had shards of glass and airbag dust in my eyes. I could barely answer the paramedic’s questions; how had I managed to perform acrobatic tricks just minutes earlier?

The answer lies in the functions of the autonomic nervous system, a branch of the central nervous system, which is what operates involuntary body functions, including breathing and blinking. The autonomic nervous system operates the sympathetic and parasympathetic nervous systems. The first perks up in a fight-or-flight situation, where danger is perceived. It releases adrenaline, a hormone also known as epinephrine, in response to fear or anxiety. It dilated my eyes and heightened my other senses, allowing for a higher intake of information. It also increased my blood pressure, which let oxygen travel quickly to my muscles and brain, explaining my circus-stunt escape route. Adrenaline powered my body in preparation for an attack or to flee. I wasn’t about to fight my Chevrolet Blazer, so I did everything I could to put distance between it and myself.

As soon as I was safe, my parasympathetic nervous system took over. The norepinephrine (the opposite of adrenaline) slowed my breathing, lowered my blood pressure and relaxed my muscles. My body had entered a long-term state, beginning the process of assessment and healing.

I’m glad to say that despite the severity of the accident, everyone involved was able to walk away. Now, I’m still in physical therapy and I will forever have scars of the accident, but my body took care of me in the moment.

Have you ever experienced unusual focus or strength in the face of danger?

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Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.