Why Your Gut Reacts to Things That Haven't Happened Yet (Part 1 of 3)
Have you ever felt your gut begin to tighten the night before a meeting — before anything has actually gone wrong?
Most people call that feeling "anxiety" and leave it there. But that word is doing far too much work. It's hiding at least four different things — and if you can't tell them apart, you can't actually do anything about them.
Why is understanding anxiety and its impact on IBS so important?
IBS symptoms are often intensified during anxiety, acute stress, or chronic stress.
The gut of someone experiencing IBS may also be more reactive during these states, and slower to return to its previous level of functioning.
This isn't a fringe issue. A 2019 meta-analysis pooling 73 studies found that around 39% of IBS patients report clinically significant anxiety symptoms, and 23% meet criteria for a diagnosed anxiety disorder — roughly three times the odds seen in people without IBS.
If you're experiencing both, you're far from alone.
The IBS–Anxiety–IBS loop
IBS itself can trigger both anxiety and acute stress. The anticipated risk of another flare — before a big meeting, a long drive, a meal out — can trigger anxiety. When symptoms actually appear, they can trigger acute stress if your survival system interprets them as a present danger.
How the anxiety–symptom loop becomes self-reinforcing
Anxiety and acute stress can influence the gut through several connected pathways — the autonomic and enteric nervous systems, hormonal signalling, and changes in attention to gut sensations.
Together, these alter gut activity and sensitivity in ways that may amplify symptoms.
And so a vicious, self-reinforcing cycle is created: IBS symptoms become the trigger for more anxiety and acute stress, which can maintain or amplify IBS symptoms.
Why targeting only one side often falls short
Because anxiety and IBS symptoms can reinforce each other, an approach that targets only one side may leave part of the cycle untouched.
This is part of why gut-directed hypnotherapy (GDH) has a strong evidence base behind it. Randomised trials show that GDH can improve IBS symptoms, and some studies also report improvements in psychological measures such as anxiety.
Its precise mechanisms are still being studied, but it is designed to influence gut-brain communication and responses to digestive sensations. We'll come back to how it fits into this picture across this series.
To break the cycle, you need to know exactly what you're dealing with
When it comes to anxiety, that's not as easy as it sounds.
Perhaps you've spent many an evening googling "anxiety" after a demanding workday and before tomorrow's client meeting, and come away more confused than when you started. I'm not surprised — the terminology isn’t exactly straightforward.
Open three different books or websites on anxiety and you'll meet: anticipatory anxiety, situational anxiety, free-floating anxiety, diffuse anxiety, chronic anxiety, disordered anxiety, state anxiety, trait anxiety, worry, worrying — sometimes used interchangeably, sometimes contradicting each other, and almost never defined clearly enough for a reader to know which one applies to them.
The confusion isn't you — it's four different questions, flattened into one word
Most of those anxiety terms above aren't actually competing definitions of the same thing. They're answers to four different questions, all labelled "anxiety":
Timing — is the perceived threat still ahead of you (a perceived risk), or already here (a perceived danger)?
Duration — is this a one-off, or an ongoing pattern?
Trigger — is the perceived danger or perceived future danger tied to a specific, identifiable cause — for example, the risk of experiencing another IBS flare-up — or is there no single cause you can point to?
Severity — is this anxiety roughly proportionate to the perceived risk (a normal, functional early-warning response), or has it become disproportionate, frequent, or intense enough to interfere with your performance, decision-making, or client-facing situations — in which case it may need professional support?
When "anxiety" is asked to carry all four questions at once, no wonder it feels like nobody's on the same page.
A cleaner starting point
Here's the distinction I use with my IBS clients, and it resolves most of the confusion in one move.
Anxiety is a state — so is an IBS flare.
A state is whatever you're experiencing at a given moment — thoughts, emotions, physical sensations, and automatic behaviours, all at once.
For someone with IBS, anxiety may show up as catastrophising thoughts ("my gut may betray me, and I won't be able to manage it"), heightened gut awareness, and automatic behaviours like tensing the belly, jaw, shoulders, or pelvic floor as a protective brace. Physical sensations commonly include muscle tension, restlessness, nausea, and a racing heart.
An IBS flare creates its own changing state too — its own combination of physical sensations, thoughts, emotions, and protective behaviours. That's why the two states, anxiety and an IBS flare, don't stay separate. They interact through overlapping gut-brain pathways, heightening each other, exactly as described above.
How is the anxiety state created?
Anxiety is a state experienced as a result of your survival response being activated in response to a perceived risk.
The state may persist while your survival system continues to register the risk as unresolved — even after the original worry thought has passed. This is part of why anxiety can outlast the original trigger if nothing's been done to actually address or reassess it.
A perceived risk is a future situation or event identified as a possible danger to your physical or emotional wellbeing — a source of possible harm, not harm itself. For example: you have a new client meeting scheduled for tomorrow at their premises, and you don't know if you'll have easy access to a bathroom.
What's the difference between anxiety and acute stress?
As above: anxiety is a state experienced as a result of your survival response being activated in response to a perceived risk.
Acute stress is a state experienced as a result of your survival response being activated in response to a perceived present danger.
So — if the perceived danger is in the future, it's a risk, and the result of responding to that risk is anxiety. If you're currently exposed to danger, the result of responding to that danger is acute stress.
Take the two days before a client presentation compared to the ten minutes you're actually presenting. The dread beforehand is anxiety — responding to the perceived risk of things going wrong. What you feel mid-presentation if your gut suddenly acts up is acute stress — responding to what's happening right now.
You may be aware of the risk, or not
In the language of this series, I use "threat detection network" as a practical label for the brain systems that are constantly pattern matching for possible danger and risk (possible future dangers). Pattern matching means your threat detection network compares incoming sensory information with its memory bank of known threats or risks to see if there's a match.
You may become aware of a risk in the form of a worry thought — or you may not. The risk may remain outside of your awareness.
When we're not aware of the risks that trigger anxiety, the resulting anxiety is referred to as diffuse or free-floating anxiety. Within this model, that's anxiety whose perceived risk hasn't surfaced into conscious awareness.
This is the "I don't know why I'm anxious about tomorrow's meeting, I just am" experience — your survival system has identified a risk even though you can't consciously identify it.
Key Takeaways
Anxiety is a state your survival response creates in response to a perceived risk (something ahead of you); acute stress is the same system responding to a perceived danger (something happening right now).
An IBS flare and anxiety are both states that can interact through overlapping gut-brain pathways, creating a self-reinforcing cycle.
You can be anxious about a risk you're not consciously aware of. Within this model, that's diffuse or free-floating anxiety — anxiety whose perceived risk hasn't surfaced into conscious awareness.
Watch out for Part 2
Part 2 builds directly on this: the difference between a worry thought and worrying, and the roles they play in a typical IBS anxiety episode.
Before Part 2 — I'd genuinely like to know: what's your gut's "night before" trigger? Drop it in the comments — a meeting, a flight, a meal out, a first date. We'll come back to how to actually respond to it once we get to Part 3.