The Fight or Flight Response

Sometimes you just have to stand up and fight

Fight or flight response
The fight or flight response: the survival instinct that drives your determination to face threats
and overcome problems.

And sometimes you don't

Sometimes you must find instead the judgement, the courage, and perhaps the generosity of spirit, to know when to back away.

Fight or flight. As we face our challenges through life, large and small, we must choose how we will respond.

Attack, they say, is the best form of defence. And yet sometimes tactical retreat is better; abandon the battle and win the war. Live to fight another way.

To some situations we must react with urgency; others demand deliberation and delay.

Success and survival depend on our ability to choose and act wisely and well.

Where can we find the strength to cope with crisis and challenge?

Fortunately, the very strength you need lies right there within you.

Our human bodies have evolved with an extraordinary capacity for survival against seemingly the most impossible odds.

You have an inbuilt fight or flight response that's there to help you deal successfully with the most dangerous of emergencies.

But as we shall see, this capacity has itself become a dangerous threat to our wellbeing in the modern world.


1  The quick and the dead

Evolution has fashioned our bodies for fight or flight

This survival mechanism empowers us to confront danger or escape it

Once essential for survival, in the modern world this mechanism is a mixed blessing. It can help you survive disasters and succeed in endeavours; and it can stress you out and make you sick.

Imagine yourself as an early human. Your small hunter-gatherer tribe is one of many scattered along the edge of the jungle where it skirts the plain, the thick primeval growth melting into great grassy plains. It is the very dawn of human existence.

You are out walking with friends, gathering fruits, berries and other edible plants to take back to your village. The heat is oppressive in the steamy jungle as you press forward, eager for a refreshing drink from the cool stream a short distance ahead. Members of your family and a few others from the tribe are with you. It's a pleasant afternoon punctuated with carefree chatter and occasional laughter.

The fight or flight response Fight or flight: Fear confronts you. Survival demands
an instant response.

Suddenly you freeze. In the clearing before you, you see the tiger.

Fear grips you.

Your mind races. The tiger has cubs. It will feel threatened. The jungle around is thick. It may feel cornered. Desperate.

The animal growls menacingly, eyes darting about to sum up the situation. You are doing the same.

You quickly sense the tiger is going into attack mode; crouching, ready to spring.

Big, powerful, aggressive. She will reach you with a single lunge.

Several members of your family, and some others in the group, have caught up with you.

All are unprepared for what they see. There is a stifled scream of dismay.


What do you do next . . . ?

In the modern world we rarely need to deal with a desperate tiger.

But for 99% of the time that humans have walked the earth, it was a common enough occurrence. Wild animals, unfriendly tribes, raging fires and floods and rock slides - any number of physical emergencies might be faced in a single day. Survival required an ability to deal with immediate physical danger.

Survival was only for the fittest. There were the quick and the dead.


2  Designed for survival

Evolution has equipped us well to deal with sudden danger

Early humans frequently had to deal with physical emergencies

They might at any time be attacked by wild animals or hostile neighbors, or face the fury of nature in the form of fire, flood or falling rocks.

Primitive humans usually had to react quickly to danger. They had recognize it, sum up a situation instantly and choose to either stand and confront it, or flee from it. Fight or flight.

Evolution has programmed our bodies with a first-rate survival mechanism for quickly responding to the threat of immediate physical danger. It's commonly called the fight or flight response.

When you fear you're about to be eaten, your body responds with a burst of chemicals that provide the wits and energy you'll need to handle the emergency. Fright; fight or flight.


3  How fight or flight works

So just what, exactly, is the fight or flight response?

Your body is still programmed, as was in primitive times, to protect you from the threats and uncertainties of a prehistoric world

Walter Cannon was an American physiologist, professor and chairman of the Department of Physiology at Harvard Medical School. In 1915 he coined the term fight or flight to describe an animal's automatic biological response to threats.

A similar pattern of reactions occurs in humans.

When a hungry animal suddenly attacks you in the jungle, you certainly do need a fast-acting arousal and survival system.

Here's how it works:

When danger threatens, your adrenal glands release adrenalin (known as epinephrine in the USA), norepinephrine, cortisol and other hormones and chemicals designed to carry out important functions necessary for dealing with the threat.

The effect is to make you more alert and to help you to run faster or fight harder. Your heart rate increases, you begin to sweat, your breath becomes shallower, and your senses become more acute.

Here are some of the more important things the fight or flight response does:

  • increases your heart rate and narrows your blood vessels (increasing your blood pressure), delivering more oxygen, blood sugar and other nutrients to your heart-lung system and to power important muscles to run or fight. As a result, your muscles and tissues tighten, and you tend to hold your limbs and torso tighter, ready for action

  • increases sweating in an effort to cool these muscles, helping them stay efficient, and to secrete body wastes, making the body lighter

  • thickens your blood to increase oxygen supply (red cells), enable better defense against infections (white cells) and to reduce bleeding (platelets)

  • diverts blood to your large muscle groups to help you run or fight, and away from the skin to the core of our bodies, reducing blood loss if you are damaged

  • sharpens your senses. Your pupils dilate and your hearing is heightened, facilitating a rapid response

  • focuses your attention on the threat, to the exclusion of everything else. Prioritization comes from an increased blood supply to peripheral muscles and the heart, to motor and basic-functions regions of the brain

  • slows down, or even shuts off, your digestive system and irrelevant brain regions (like speech areas) so as not to waste blood, nutrients and oxygen that could be used to run or fight

  • secretes endorphins which are natural painkillers to provide an instant defense against pain.

All of this significantly improves your ability to survive life-threatening events.


4  Fear in the modern world

Why your primitive body chemistry has become a modern menace

The fight or flight response was invaluable in primitive times

Your very survival then depended on it. You faced the frequent danger of sudden attack from hungry animals, unfriendly rivals or raging storms.

We no longer fear wild beasts and sudden ambush. But our world today is infinitely more complex than that of our paleolithic predecessors, and the 'dangers' we fear are far more complicated and subtle.

Fight or flight
Today's threats are a far cry
from facing down a tiger.

Today, our fears take many forms: we worry over deadlines, debt collectors and unemployment.

Working and living in our cities and towns, we rarely now encounter the threat of immediate physical danger. We have a very limited need for the fight or flight response.

But while the 'emergencies' we confront today are a far cry from facing down a tiger, your body doesn't know that.

Whether you are threatened by a deadly beast or a demanding boss, your body reacts the same way every time: it invokes the fight or flight response.

Your body is programmed to treat any stimulus that triggers fear as if it threatened immediate physical danger.

Fear may be experienced as any of the so-called 'negative' emotions that sometimes disturb your equilibrium, disrupting your feeling of safety and security. Examples include anxiety, panic, dread, concern and despair.

These are all forms of fear as far as your body is concerned.

Any stimulus that triggers fear (in any of its forms) will invoke the fight or flight response.

A stimulus that triggers fear is what we commonly call a threat.


5  Our threats are commonplace

The fight or flight system is activated if your brain perceives a threat of any kind

Your brain sees as a threat any disturbance that places demands on you, physically, emotionally, psychologically or spiritually

A threat may be external (physical/social) or internal (emotional/psychological); it may be real or imagined.

Just about anything that 'upsets' you will flick on the fight or flight switch.

The danger you perceive does not have to be life-threatening.

It does not even have to be 'dramatic.'

You can experience the flight or fight response simply by being frustrated or by experiencing a situation that's new or in some way challenging.

The threat does not even have to be real. An imagined threat will invoke the response.

Recent research shows that we experience the fight-or-flight response even when simply encountering something unexpected.

Your body does not need to know or understand the source of the threat. It just recognizes that a threat exists, and reacts automatically as it is programmed to do.

And the cause of the danger is irrelevant. What matters is your ability to respond rapidly and effectively to anything that may arise out of the threat. When you do meet with immediate physical danger the situation can unfold quickly and unpredictably.

Your body draws no distinction between various types of threat.

It moves swiftly into fight or flight mode, preparing you for any demands that may result, releasing its cocktail of chemicals into your bloodstream. These chemicals increase your alertness, perception, energy and strength for dealing with any situation.

This of course is ideal when you face a threat of immediate physical danger. It enables you to immediately get physical: to fight, run, jump, kick, scream, dive, shove, whatever, in order to fight or flee.

But getting physical isn't the best way to manage the fears we mostly face in modern times.


6  Our threats are complex

Most threats we face today can't be met 'physically'

We're rarely confronted these days by wild animals or spear-throwing rivals

Instead we encounter debt and deadlines, competitors and commitments; we face family feuds, social stigmas and crowded agendas.

'Impossible' demands are placed on our limited time, energy and capacities. We worry that we can't make ends meet or keep everyone happy.

Of course you can deal with some demands immediately - you can grab the rail before you fall overboard, jump clear of that approaching car, or sit down now and patch up that quarrel with your sister.

Many modern challenges however are complex. They have these twin characteristics:

  • you can't resolve them with physical action.

    When physical action isn't practical, or doesn't remove the source of threat, your stress chemicals do not get burned up; they linger and cause the emotional and physiological experiences we call stress.

  • you can't resolve them quickly.

    Prolonged anxiety, worry or frustration is caused by the ongoing nature of so many issues in our modern world. Because you can't respond appropriately to these demands, you continue to produce survival chemicals over long periods. Your feeling of stress mounts over time.

Complex problems today often demand a calm, measured rational response; one that is socially sensitive, controlled, carefully crafted and weighed against competing or conflicting needs. Decisions and agreements, rather than direct actions, are called for.

Such complex issues can take a very long time to resolve.

And in the meantime they continue to cause anxiety, frustration, and other emotions that trigger the stress response.

When an immediate physical reaction is not practical, your automatic fight or flight response leaves you awash with survival chemicals you can't use.

So you have this flood of chemicals coursing through your body for potentially ages with nothing (physical) to do. A solution without a problem. And there's no way for you to 'burn up' these chemicals.

You become agitated and irritable, unable to concentrate. Your heart beats faster, your blood pressure shoots up, your temperature rises and you start to sweat. Your muscles get tense and you feel 'uptight.'

You are experiencing stress.


7  The stress response

If you can't react physically and immediately to a threat, what happens to this wash of unwanted chemicals?

It's not good news!

Rather than help you, your dose of fight or flight chemicals actually diminishes your capacity for confronting common 'dangers' in today's world:

  • filled with adrenalin (epinephrine), you tend to become excitable, anxious, jumpy and irritable (sometimes called an adrenalin rush) or adrenalin response).

  • this diminishes your ability to work effectively with other people

  • it's hard to execute precise, controlled skills when you're trembling with a pounding heart

  • your intense focus on survival interferes with your ability to draw subtle information from multiple sources to make fine judgments

  • you become more accident-prone and less able to make good decisions

While this may sound pretty discouraging, it's not the worst of it.

The very same chemicals intended to save your life in the immediate term may cause illnesses in the medium term, and can even kill you over the long term. The fight or flight response is often called the stress response, because stress is the name we give to the above symptoms.

The effects of long term stress on your health can be serious. It's important you act now to reduce the long term stress in your life. Remember:

Long term stress is a stalking killer.

If you came to this page from the prompt in 'What is stress?' you can return here. Otherwise follow one of the links below to find out more about stress.

Stress icon

Learn more about stress and its causes

Many experts believe stress is among the biggest killers of our time. Research has linked it to leading causes of death including cancer and heart diseases. Long term stress can cause serious, irreversible and even fatal damage.

Are you stressed? Find out now if you are at risk.

The worst thing you can lose in life is your health!

If you haven't done so, start at the beginning, where we ask what is stress?

If you're feeling crushed by a continuing failure to cope with distressing demands in your life, you may be suffering from learned helplessness. Learn how to recognise and deal with this condition.

If you are feeling overwhelmed by life events bringing significant changes in your life, try this life events stress test.

See if you identify with some of these common physical symptoms of stress or these common mental signs of stress.

Discover how causes of stress work and read this overview of the the biggest causes of stress. The seven biggest causes of stress are summarized below, with links for more detail on each.

And finally, beat stress in your life! Use stress management techniques to overcome your biggest causes of stress.

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