Fear - 'a great tool' of innate survival mechanism

'Fear increases our ability to concentrate, strengthens our muscles, and prepares us to respond to whatever situation comes our way,' says a psychologist at Oxford University's Emory University.

Watching horror movies, going to haunted houses or playing pranks on friends are usually harmless activities. But the fear they cause can trigger the body's 'fight or flight ' system - releasing chemicals into the body and causing a number of physiological responses.

" The body's fear response is actually a great survival tool in dangerous situations because it's quick and gives us a burst of energy," says Kenneth Carter, a clinical psychologist at Emory University's Oxford College of Psychology.

Fear improves concentration, strengthens muscles, and prepares us for any situation that may come our way."

Picture 1 of Fear - 'a great tool' of innate survival mechanism
Fear enhances the ability to concentrate to deal with the upcoming situation. (Illustration: National Geographic)

" This is an innate survival mechanism that has existed since ancient times when humans had to flee from predators, " adds Janice Kiecolt-Glaser, director of the Institute for Behavioral Medicine at Ohio State University College of Medicine .

But even though this mechanism helped our ancestors escape saber-toothed tigers and helps us stay away from dangers today, triggering the body's fear response isn't always a good thing.

'If fear is triggered repeatedly, or sudden scares happen frequently, it can weaken our bodies,' says Carter.

Fear reaction

The body's fear response always begins in the amygdala — part of the brain's limbic system that plays a key role in threat perception and emotional processing.

Once a threat is perceived, the amygdala sends distress signals to a command center in the brain called the hypothalamus, which orders the nervous and endocrine systems to release hormones and neurotransmitters such as cortisol, dopamine, noradrenaline, and adrenaline.

'Neurotransmitters are released from nerve cells in the nervous system, while hormones are released from the adrenal glands—a pair of endocrine glands that sit above the kidneys,' explains Marc Dingman, a biobehavioral health scientist at Pennsylvania State University.

Research shows that these hormones and neurotransmitters work together to increase breathing rate and help the heart pump oxygen-rich blood more quickly to muscles and vital organs. This prepares the muscles and brain to quickly coordinate a response to a threat.

In such a state, "our muscles tense up, so we're ready for action; our pupils dilate, so we can see more clearly; our minds sharpen, so we can focus fully on the threat; and our hearing improves, making us more sensitive to sound," Kiecolt-Glaser explains.

The release of adrenaline also reduces pain by inhibiting signaling pathways, so we can run farther or fight harder than we would normally be able to endure.

Although stress hormones play the biggest role in these changes, fear also prompts the body to release dopamine to further increase alertness.

'This may contribute to the unexpected sense of pleasure that some people often experience in fear-induced situations,' says Emily Hemendinger, a stress management researcher at the University of Colorado.

Real and fake threats

Holly Blake, professor of behavioural medicine at the University of Nottingham Medical School in the UK, says our immediate biological response to fear is the same – whether we are facing real danger or something that only seems dangerous.

For example, a situation where an 'actor' wears a scary mask and chases you through a 'haunted house' with a fake chainsaw will be stressful for you in the same way as a real killer with a real chainsaw.

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Smaller amounts of stress hormones are typically released during fear. (Illustration: Medium).

Your brain usually knows what these threats are, but sometimes it doesn't know what's real or what's not. Think of a friend who dresses up to scare you or a horror movie experience.

Because our brains evolved in the real world billions of years before movies began to be produced, our brains sometimes determine what we see on the screen as real.

This explains why 'Jaws' - a movie shot with a mechanical killer shark - scared millions of people as if they were facing a real shark.

In these situations, the body's full 'fight or flight' response may not kick in. Instead, smaller amounts of stress hormones are often released, leading to effects like a racing heart, sweaty palms or feeling jittery.

'Although harmless and enjoyable for many people, frequent fears can be stressful, even for people who think they enjoy them,' says Mihail Zilbermint, MD, director of the endocrinology program at Johns Hopkins Medicine.

Kiecolt-Glaser explains that when stress hormones are released too often or for long periods of time, "it can wear your body down."

' In some people, it can lead to health problems like high blood pressure, heart and digestive problems, or immune system disorders because your body is constantly on "high alert" mode.

And because adrenaline has been found to damage heart tissue in some people, people with heart conditions need to be especially careful. "I would recommend avoiding intentional scares if you have arrhythmias," Millstine advises.

The same goes for people with chronic back pain, "because sudden muscle contractions that occur when in pain can cause muscle spasms and flare-ups of symptoms," she says.

Overexposure to scares can also desensitize you to fear – again, fear is an important evolutionary survival response.

'People who enjoy horror movies or frequently visit haunted houses may not react as strongly to real danger, because their brains have become accustomed to these situations through a process called 'habituation,'' Carter says.