Here are some of the ways that fear can either halt us or help us.

It was a beautiful day in the most cliche of ways: the sun was shining, the sky was blue and the clouds looked almost perfectly plump. Even my actions fit the typical Southern California stereotype: I was shopping at the flea market, which was just about to come to an end. Yet, as I started to walk toward the gate to exit, my “normal” day nearly ended as well.

Suddenly, everyone around me started running in different directions. I heard whispers and shouts that there was a man with a gun running loose around the neighborhood. Within seconds, the man was 20 feet away from me on the other side of the gate, yelling like a maniac and waving his gun in the air. I couldn’t stop news headlines of past shootings from flying through my mind.

I dropped behind a table draped only by a flimsy table cloth; a few other women huddled beside me. We knew we were not safe and, collectively, we decided to make a run for better shelter. It felt like adrenaline – not blood – was pumping through my entire body, as my brain, my heart, my veins, my lungs, my fingers all focused one goal: running to safety. And I had fear to thank.

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Taking a trip back to high school biology, you probably remember a biological process known as “fight or flight.” When animals or people perceive a threat, their sympathetic nervous systems undergo changes resulting in either intense fear (leading to flight) or anger ( leading to fight).  This fear-triggered reaction heightens people’s senses and quickens their ability to make decisions. At the same time, adrenaline floods a person’s body, increasing heart rate and blood flow. All of these changes helped humans’ ancestors escape or battle dangers to survive – and can even result in “hysterical strength” that allows people to perform typically-impossible physical feats (like lifting a car off a loved one).

Some believe that fight or flight process – and the fear that initiates it – may have helped ancestors survive, but no longer aids the modern man or woman. For instance, Dr. Jim Taylor at Psychology Today points out that “unlike threats of the past, today’s are often neither immediate, foreseeable, or understandable, much less controllable.” Instead of evading a mountain lion, people today need to deal with not getting the promotion they wanted…and the two reactions triggered by “fight or flight” (like yelling at your boss or crying and never returning to work) will cause more harm than good.

However, fear is still a valuable survival instinct. As I was running with the other women away to safety, I remember how clearly my brain was thinking but how scared my body felt. That it was fear-triggered adrenaline pumping through my veins so that I could take action towards safety.

Fear can be helpful in more situations than just life and death, too. As Jeff Wise in his book, Extreme Fear: The Science of the Your Mind in Danger, explains, fear can give people seemingly “superhuman” strength – not only to save others, but also to break world records in high-stakes competitions like the Olympics.

However, while fear was helpful and extremely vital to my survival that day (the police took the gunman into custody before he was able to harm anyone), it can also get in the way of immensely important experiences and states of being such as happiness, pleasure and success.

Think of this way: there are two types of fear, healthy and unhealthy. Healthy fear is the fear that I experienced that day – the type that rightfully goes off in harmful situations that warns or prompts you to take the right action. Or, it’s the kind of fear that “unleashes reserves of energy that normally remain inaccessible” and fuels almost unbelievable physical feats.  But unhealthy fear tells you that you can’t do it and masks the reasoning behind rational choices.

When fear hides as common sense or rationality, it is really halting you from achieving success, diving into new experiences and creating new connections. In fact, fear can trap you in a world of “pain, paralysis and depression,” as Dr. Susan Jeffers analyzes in her book, “Feel the Fear and Do It Anyway.”

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Have you ever wanted to start a new business but find yourself making excuse after excuse as to why you can’t or shouldn’t or won’t start?

While usually our excuses seem to be based on rational criteria, the bottom line of why we don’t do things is usually because of fear – and “at the bottom of every one of your fears is simply the fear that you can’t handle whatever life may bring you,” according to Dr. Jeffers.

I have experienced my fair share of healthy and unhealthy, rational and irrational fear. I have even realized that healthy fear – which saved my life – can lead to unhealthy fear. As I ran for safety that day at the flea market, I applauded myself for helping me react quickly to a situation I had never experienced before. Yet, moving past the shooting has proven to be a lot slower of a process.

Although I would not claim to have PTSD, studies have shown that mass shooting affect survivors long after the shooting ends. In fact, the National Center for Post-traumatic Stress Disorder found that, out of 136 survivors of one mass shooting, 20% of the men and 36% of the men fit the criteria for PTSD. On a follow-up with the victims one year later, 28% still struggled with PTSD. Some of the best ways to cope? Embracing pragmatism, refusing to abandon control and actively reaching out to others.

Moving past less extreme forms of unhealthy fear – like the kind that prevents you from fully experiencing so many exhilarating, challenging and beautiful things in this world – uses similar techniques.

While Dr. Jeffers includes a variety of different methods to empower yourself against fear in her book, they boil down to one point: “All you have to do to diminish your fear is develop more trust in your ability to handle whatever comes your way!”

Today, I always try to analyze my decision-making process. Before I make a decision, I call on my friend: fear. I try to figure out whether fear is either hiding, harming or helping in the situation. If fear is the only reason that I am not saying yes to something, I force myself to say yes. If fear is not present and the evidence against the decision is pretty substantial (example: that’s not a good fiscal decision or that will hurt others), then I decline the opportunity. But in all that I do, I assess where fear stands: with me, against me or absent.

READ MORE: How to Combat Fear

Learning when fear halts you and when fear accelerates you can be the game changer between leading an ordinary live and leading a successful, adventurous one. And, in some cases, fear can be the key to staying alive.

Edited by Casey Cromwell