What really happens when you’re afraid?

Your heart is pounding in your chest, your breathing is heavy, your hands are clammy and your muscles are tense. You’re terrified, and whether it’s from a fake zombie at a haunted house or something closer to reality, the reactions that your body goes through are no trick (or treat).  But what are those reactions? What is really going on when you’re scared?

According to Dr. Mary Lamia in her article “The Complexity of Fear,” being afraid starts with observing a change in the environment, whether visually, through touch, smell, or any other sense.  When you sense something scary, Lamia writes, a specific area of the brain, the hypothalamus, triggers the “fight or flight response.”  The hypothalamus exists as part of the so-called lizard brain, one of the most primitive parts of human brain, and is responsible for basic functions like breathing and beating the heart, reproducing and deciding whether or not to run from or fight off danger.

“The lizard brain takes over when you need to make a quick decision that could mean life or death,” says Dr. Tony Hampton, family medicine physician with Advocate Medical Group in Chicago. “It is a product of the time when humans had to run from predators, though if it’s a saber tooth tiger or an unavoidable car accident, the reaction is the same.”

After your fight or flight response kicks in, your hypothalamus will tell the rest of the body to flood itself with hormones designed to make your ready for action.  This begins with cortisol, which in turn sends signals to the adrenal glands to ramp up production of epinephrine, otherwise known as adrenalin.  It is epinephrine that is ultimately responsible for the changes in your body when you’re afraid.

In her article, Dr. Lamia describes what adrenalin does to the body: first, your heart rate will increase and your blood pressure will rise, delivering more oxygen and blood to your muscles to ensure that you are ready to move or fight.  You’ll start to sweat because your body temperature is rising and your pupils will dilate in order to let in as much light as possible, making it easier to see and increase your reaction time.

Adrenaline doesn’t just supercharge some parts of the body though – according to Dr. Hampton, when in danger, your body will shut off areas that wouldn’t be useful in a life or death struggle.

“Think about it – when you’re terrified, are you thinking about how hungry you are?” Dr. Hampton says.  “The answer is no, so your body will divert energy away from your stomach and digestive tract to the areas it needs right away.  Your body will shift its priorities away from things that are less important.”

While all these reactions may sound extreme, Dr. Lamia maintains that stress is and should be a part of everyday life.  However, too much stress can be a bad thing, putting strain on the heart and causing headaches, issues with behavioral health or even infertility.  But as quickly as it comes on, stress can also be avoided through meditating, exercise or just simply taking the time to clear the mind and relax.

So on Halloween, when a latex ghoul or other monster jumps out to scare you, take a deep breath and remember it’s not real, even if your lizard brain is telling you to head for the hills.