Stress: What Happens Inside You?

You're sitting in class when your teacher announces that the presentation order has changed. Instead of presenting last in two days, you're going first this afternoon. Before you've had much time to think about it, your heart is beating faster. Your stomach feels tight. Your palms are sweaty. And suddenly the presentation seems to have taken over most of the available space in your brain.

Early that afternoon, someone makes a rude comment to you in the hallway. You might immediately snap back, walk away, find yourself unsure what to say, or try to smooth things over so things don't get worse. You probably didn't stop and carefully choose from those four possibilities. Your reaction may have already started before you had much time to think. The racing heart after the presentation announcement and that quick reaction in the hallway might not seem to have much in common. Underneath both, though, is the same remarkable system built into your brain and body.

This is your Acute Stress Response.

So, How Does Your Body Do That?

Your brain is constantly taking in information about what is happening around you and inside you. In the background, it is evaluating what matters and whether something needs more of your attention. When something seems threatening, uncertain or important enough, your brain can activate the stress response before you have deliberately thought through what is happening. A small area called the hypothalamus helps send that message into the nervous system. The sympathetic nervous system quickly carries the 911 message to the whole body to respond. Adrenaline is released. Your heart beats faster. Breathing changes. Muscles prepare for action and more energy becomes available. Even digestion changes for a while, which helps explain why stress sometimes shows up as butterflies, tightness or nausea in your stomach.

Question: Well, would you be more focused than if this were a little kitty cat running at you?

Oh yes, and your brain changes what it is doing too. Think back to that presentation announcement. A few seconds earlier, you might have been listening to your teacher, thinking about lunch and noticing the person beside you. Then you hear, You're presenting this afternoon. Suddenly, the presentation gets most of the attention. Your teacher keeps talking, but several minutes later you realize you haven't heard much of it. Basically there are sudden surprises that capture your whole attention immediately and you forget everything else you were doing and become focused, like turning around and seeing a bear running your way. Your attention becomes very focused toward what your brain has decided matters most.

Why Would Your Brain Do That?

For most of human history, a possible threat could require an immediate response. If something dangerous was approaching, focusing on that threat while your heart, muscles and available energy prepared for action could help keep you alive. There wasn't much value in giving equal attention to everything else happening around you. Your stress response is an ancient survival system. It is there to protect you.

And stress is not automatically bad. Some activation can make you more alert, attentive and ready to meet a challenge. But as stress becomes much stronger, more of your attention can become locked onto the immediate problem and flexible thinking becomes harder.

Would your brain respond the same way if this were a little kitty cat running toward you?

The prefrontal cortex helps you hold information in mind, weigh different possibilities, think flexibly and decide what to do next. At very high levels of stress, those kinds of thinking become more difficult as your brain gives priority to whatever seems most important right now. If a bear suddenly appears on a hiking trail, this is useful. Your brain does not need to consider tomorrow's homework, what your friend said at lunch and six possible interpretations of the bear's intentions. There is one immediate problem. Almost everything else becomes background noise.

Fight, Flight, Freeze or Fawn

Now come back to that rude comment in the hallway. The biology hasn't suddenly changed because the "threat" is social rather than a bear. Your stress response can still activate, but what happens next is not fixed.

Four commonly described responses are fight, flight, freeze and fawn. Fight means confronting what feels threatening. Flight means getting away or avoiding it. Freeze can mean becoming quiet, still or temporarily unsure what to do. Fawn describes trying to reduce the conflict by agreeing, pleasing or calming someone because that feels safest at the time. Now the hallway makes more sense. Snapping back might be a fight response. Walking away could be a flight response. Finding yourself unable to say what you wanted could be a freeze response. Trying to smooth everything over might be the fawn response.

Different reactions. The same remarkable stress-response system underneath them. And that leaves us with a much more interesting question. If we all have this stress-response system, why can something feel completely manageable one day and overwhelming on another?

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