Physiological Gut Responses and their Emotional Connections

Pedram Shojai
3 min readApr 6, 2021


The Urban Monk

If you’ve ever felt your stomach twist into knots and recognized you felt nervous, congratulations.

You’re human!

Now that science is getting wise to the brain-gut connection, we’re realizing that we’ve been intuitively paying attention to the subtle signal of the gut for much longer than we knew.

But for a lot of history, we’ve written off gut reactions as illogical, sensitive, and generally unsubstantiated.

We were wrong to think so. There are actual, scientific reasons for these sensations that we’ve long assumed to be emotional.

Everything from “my stomach is twisted into knots” to “I’ve got butterflies in my stomach” to having a “pit in my stomach” has an evolutionary purpose. All of those feelings, which are common enough to have become cultural idioms, are based in reality.

Let’s explore what happens in your actual gastrointestinal tract that simulates butterflies and excitement, a twisted knot and nervousness, a stomach drop and disappointment.

Butterflies And Excitement

Having “butterflies in your stomach” is commonly associated with falling in love, anticipating a first kiss, or feeling eager before a job interview.

Here’s what happens: The emotional part of your brain, or the limbic part, signals the vagus nerve, which is the nerve connecting your brain to your gut.

Now, to your brain, nervous and excited look the same.

So whether you’re waiting to hear back from a brand-new crush, or you’re on the way to your third interview at your dream company, your brain can’t tell the difference because technically, those feelings are the same. (It’s just the spin.)

When you experience excitement, your thoughts trigger the pituitary gland to tell the adrenal glands to release adrenaline.

This pulls blood to your lungs and muscles (to activate your fight-or-flight response) and away from your stomach.

Boom! There are your butterflies.

Twisted Knot and Nervousness

Feeling anxiety is a little bit different from feeling excitement.

Now, granted, your brain can generally tell the difference between the positive tension when you’re about to propose to the love of your life, and the negative tension when you know you did something wrong at work. But the root of both feelings does the same thing…

It triggers the fight-or-flight response.

In the case of your twisted stomach knot, here’s what’s happening…

Your muscles are tense, because that is how your body prepares for potential threats. It prepares to pounce.

Similarly to when you experience butterflies, your brain communicates to the vagus nerve that it isn’t looking forward to what’s coming next, and in response, your core muscles contract and literally become tired.

This produces what feels like a “knot” in your stomach.

Stomach Drop and Disappointment

The “stomach dropping” feels so medical to some people that they think they’ve thought themselves into a physical attack.

And although the sensation is actually physical, the root is still mental.

It’s actually a combination of what happens when you’re excited and when you’re nervous.

The fight-or-flight response triggered by the brain, because something unfavorable has happened and your first response is to guard yourself, sends cortisol rushing to the adrenal glands.

Blood pulls away from the gut and gets sent to the muscles.

And as hormones surge through our bodies, our muscles contract, and we’re left feeling the blood drain from our guts at the same time that our core muscles tighten, causing the “stomach drop.”

Even though most of the reasons we feel stress in 2021 aren’t related to physical danger, your body makes no distinction between stressors.

And it sends its messages to the gut instead of, say, the bicep, because the powerful and diverse microbiota flourishing in your gastrointestinal tract. That’s where serotonin gets regulated, after all.

So when your brain knows you’re excited, nervous, or disappointment, here’s what it knows: you’re stressed.

And it’s going to tell the gut to prepare you for whatever may come next!

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