“Butterflies in the stomach” is that fluttery, nervous feeling you might have before a job interview, giving a speech or at the start of a romance.

It’s a cute description for one part of the fight-or-flight response that can kick in if you’re excited or afraid.

But what exactly are these butterflies? Why can we feel them in our stomach? And is there anything we can do about them?

These “butterflies” – along with a raised heart rate, sweating and feeling “jumpy” – are part of your survival mode. That’s when the part of your body known as the autonomic nervous system gets involved.

When you sense a possible threat – whether it’s physical or social, real or imagined – information is sent to the brain’s amygdala region for emotional processing. If the amygdala perceives danger, it sends a distress signal to another part of the brain, the hypothalamus, which kick-starts a cascade of changes to help the body prepare.

The adrenal glands on top of each kidney send the chemical messengers adrenaline and noradrenaline into the bloodstream, activating receptors in the blood vessels, muscles, lungs and heart. The heart rate and blood flow increase, blood sugar levels go up, and muscles are primed for strength (fight) and speed (flight).

Digestion can wait until after you have escaped from the tiger (or the job........

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