Those who have been in a life or death situation say you never really know how your body will react until you find yourself in such a position. It is likely that you have heard the phrase, “fight or flight” at one point or another. The idea behind it is simple–people react to stressors to the best of their capabilities. However, its application is far more complex and is rooted deep in human nature. 

Fight or flight is a physiological reaction that occurs in response to perceived danger. It was first discovered by Walter Bradford Cannon, who noticed the trend in mammals. The connection was made that humans also experience this in a similar fashion. 

So what actually happens when someone encounters a stresser? Well, according to a publication by Harvard Health, the reaction begins within a part of the brain called the amygdala, which deals with emotional processing. The amygdala transfers the message to the hypothalamus, which distributes the message to the rest of the body through the sympathetic nervous system. Hormones are secreted throughout the body in response. Estrogen, testosterone, cortisol, dopamine, and serotonin are the hormones responsible for how the organism will react to stress. 

These hormones are released when our minds perceive adversity, in an attempt to help us have an appropriate reaction that will keep us alive. 

Blood will cease pumping to the digestive tract and be rerouted to large muscle groups, since digesting food isn’t the body’s main priority during a time of crisis. Resultantly, heart rate will increase, hands can become sweaty or cold, pupils will dilate, and adrenaline levels will be high. Sound familiar? Most people experience these symptoms throughout their day, and they are normally triggered by first world problems. Such as knowing you are going to be late for something important or an upcoming exam. 

However, this instinctual reaction is rooted back to cavemen, and their constant battle to remain alive. The fight or flight instinct evolved thousands of years go when danger was around every corner, yet today in a society with little pressing danger, it has taken a new shape. 

This stressed induced fear reaction was crucial to the survival of past generates, such as neanderthals. Knowing how to sense a predator, what locations were safe to roam, and facing general danger could all prove deadly without this instinct. Thus, the brain’s release of hormones would result in either running away, or fighting. As a result, the flight or flight reaction would have saved their life. 

However, in the setting of a highly technological first world country, such as the United States, this instinct has morphed and begun to take effect in unnecessary situations. The brain still releases the stress-induced hormones, but now in relatively harmless situations. 

The majority of the human race no longer encounters life or death situations on a regular basis, as they once have. Now, common everyday stressors such as school and work can be enough to trigger the fight or flight reaction in humans as a consequence. This leads to fear in situations that are not life threatening; which explains that pounding heart-beat before a big presentation, and why we run up the stairs as fast as possible after turning off the lights in the basement. 

The best way to put it is, our body cannot tell the difference between running from a Saber-Toothed Tiger and trying to get to school on time. Both situations trigger the same response within the body, yet one is significantly less threatening in the grand scheme of things. 

In relation to what can trigger this involuntary reaction, it is also believed to be linked to the dangers our ancestors once had to face. For example, the dark is widely feared to due to the fact that night time would bring danger in prehistoric life. So, to this day, the human brain has been rewired to have the same fear. 

Additionally, many people are afraid of spiders and bugs. This is linked to how poisonous insects could potentially kill unsuspecting subjects, as people had little protection from the elements and had a vast lack of medical resources. Hence, it is rooted deep within human nature to fear the same things that once proved lethal to people centuries ago. 

Being in a state of nearly constant fear can have detrimental effects on both physical and mental health. According to a study by the University of Rochester Medical Center, “High levels of cortisol from long-term stress can increase blood cholesterol, triglycerides, blood sugar, and blood pressure. These are common risk factors for heart disease”. 

The best way to counteract the effects fear has on the body is to moderate your reactions to different stressors, both physically and mentally. Also, keeping good physical health in general will prevent almost all other repercussions, hence why it is important to eat well and get regular exercise.  

Overall, irrational and rational fear are one in the same when it comes to the human mind. It is important to recognize this, to hopefully gain a better grasp on knowing when and how to react to situations; because at the end of the day, at least you aren’t being chased by a Saber-Toothed Tiger.