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Why do we get scared? -

Looking at evolution, fear is ancient, and we can even thank fear for our success as a species.

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Fear has saved living creatures -

Any creature that doesn't run and hide from bigger animals or dangerous situations is likely to be removed from the gene pool before it has the chance to procreate.

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Trigger-happy -

Fear's role in survival helps explain why it sometimes seems a little trigger-happy. In other words, it makes sense to be a little jumpy if you're in a hostile environment.

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What happens in the body? -

People often refer to the physiological changes that occur when a person experiences fear as the fight-or-flight response. This means you'll either stay and fight, or run.

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A lot of things are happening -

Your breathing rate and heart rate increases, peripheral blood vessels constrict, and central blood vessels around vital organs dilate to flood them with oxygen and nutrients.

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The impact on the muscles -

Also, your muscles are pumped with blood, ready to react to whatever is causing the fear.

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Goosebumps -

Muscles, including those at the base of each hair, also become tighter, causing piloerection, which we all know as goosebumps.

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Human goosebumps don't do much compared to other animals -

When a human's hair stands on end, it makes little difference to their appearance. However, for certain other animals it makes them seem larger and mightier.

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Glucose -

When we face a fear, levels of glucose in the blood spike, providing a ready store of energy if action arises. Similarly, levels of calcium and white blood cells in the bloodstream increase.

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Triggering the response -

The fight-or-flight response begins in the amygdala, which is a small bundle of neurons that is part of the limbic system. It plays an important role in the processing of emotions, including fear.

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Amygdala -

The amygdala signals the hypothalamus, which then activates the pituitary gland. The pituitary gland is where the nervous system meets the endocrine, or hormone, system.

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Pituitary gland -

The pituitary gland then releases adrenocorticotropic hormones (ACTH) into the blood.

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In comes the adrenaline -

At this time, the sympathetic nervous system gives the adrenal gland a nudge, encouraging it to release a dose of epinephrine, also known as adrenaline, and other catecholamines into the bloodstream.

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Rise in blood pressure -

The body also releases cortisol in response to ACTH, which causes a rise in blood pressure, blood sugar, and white blood cells. Circulating cortisol turns fatty acids into energy.

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Catecholamines -

Catecholamine hormones, including epinephrine and norepinephrine, prepare muscles for action if you need to fight or run.

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How hormones can further impact you -

These hormones can also boost activity in your heart and lungs, and reduce activity in the stomach and intestines, which explains the feeling of 'butterflies' in the stomach.

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Hearing and vision can be impacted - Your hearing can also be reduced, and you might experience tunnel vision due to these hormones.

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Possible tears and salivation - Also, you might experience the production of tears and salivation, explaining the dry mouth that comes with a fright. Plus, your pupils may dilate.

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Control of fear response -

A brain region that is heavily involved in memory, the hippocampus, and the prefrontal cortex, which aids high-level decision-making, help control the response to fear.

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How they help -

These brain regions help us understand whether our fear response is real and justified, or whether we might have overreacted.

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Dial back the fear -

If the hippocampus and prefrontal cortex decide that the fear response is exaggerated, they can dial it back and decrease the amygdala's activity.

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When it comes to spooky entertainment -

This explains why people enjoy watching horror movies or go to haunted houses, as their sensible 'thinking brain' can overpower the primal parts, which automate fear response.

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Why do we freeze when we are scared? -

The fight-or-flight response makes sense from a survival standpoint, but what happens when we freeze? Indeed, when frightened, most animals freeze for a few moments before they decide what to do next.

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Staying still can be good idea -

Sometimes, staying still is the best plan. For example, if you're a small mammal or if you're well-camouflaged, staying still could save your life.

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How about humans? -

Studies have found that freezing releases endorphins, which calms the body and also relieves pain. Also, freezing allows one to block out a scary experience, which may be too difficult to process.

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The question of phobias -

There's actually a difference between phobias and fears. Fears are common reactions to events or objects. But a fear becomes a phobia when it interferes with your ability to function and your quality of life.

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When extreme measures are taken -

If you start taking extreme measures to avoid water, spiders, people, etc., you may have a phobia. At that point, you should consider getting professional help.

Sources: (Medical News Today) (Northwestern Medicine) 

See also: Understanding the many different forms of therapy

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