What are some common symptoms of anxiety that no one talks about?

Lesser-known anxiety symptoms include derealisation (feeling detached from reality), digestive problems, jaw clenching and teeth grinding, difficulty concentrating or memory fog, and bone-deep fatigue from being on alert. These are physical consequences of a nervous system staying braced, not separate illnesses.

Key takeaways

Many anxiety symptoms are physical and get mistaken for unrelated health issues.
Derealisation and brain fog are common but rarely discussed symptoms of anxiety.
Digestive symptoms exist because the gut and nervous system are directly linked.
Fatigue from anxiety comes from constant low-level alertness, not laziness.
Recognising these as anxiety, not separate illness, is often itself a relief.

Why does anxiety show up as strange physical symptoms?

The nervous system doesn't separate “mental” from “physical” the way we do in conversation. When it perceives threat, it reroutes resources: blood flow shifts away from digestion, muscles brace for action, attention narrows, and sleep architecture changes. The symptoms that follow, an unsettled stomach, a tight jaw, foggy thinking, are downstream effects of a system working overtime, not unrelated health problems layered on top of anxiety.

Because these symptoms don't look like “worry”, they often go unrecognised as anxiety for months or years. People visit GPs for digestive issues, dentists for jaw pain, and opticians for eye strain, all genuinely searching for answers, before anyone connects the dots back to a nervous system that has been in a state of chronic vigilance.

What does derealisation or brain fog actually feel like?

Derealisation is the sense that the world looks slightly unreal, flat, distant, or like you're watching life through glass. It's deeply unsettling but is a known, harmless (if unpleasant) response to prolonged anxiety or stress, essentially the brain dampening input when it's overwhelmed. Brain fog feels like wading through mental treacle: words don't come easily, concentration slips, and you forget things mid-sentence. This happens because an alarmed nervous system prioritises threat-scanning over working memory and focus.

Neither of these means something is seriously wrong with your brain. They are a sign of a system that has been running hot for too long and is asking for a different kind of attention, not more analysis or googling symptoms, which often feeds the cycle further.

Why do digestive issues and jaw clenching happen with anxiety?

The gut has its own extensive nervous system and is in constant communication with the brain via the vagus nerve. Chronic anxiety alters gut motility and sensitivity, producing symptoms like nausea, a knotted stomach, or irregular digestion that mirror conditions like IBS. Jaw clenching and teeth grinding, often happening overnight without you realising, are a physical expression of tension the body hasn't found another way to discharge.

These symptoms often improve not by treating the stomach or the jaw in isolation, but by addressing the underlying state of vigilance that's driving them.

What helps with symptoms that don't look like “anxiety”?

The first genuine relief for many people is simply learning that these symptoms are anxiety, because it ends the exhausting search for a separate diagnosis and the fear that something sinister is being missed. From there, the task isn't to eliminate each symptom individually but to help the nervous system learn, through repeated experience, that it can come down out of alert.

This is slower than a quick fix, but it's the only approach that resolves the pattern rather than managing one symptom at a time. Gideon's Nervous System Masterclass works specifically with this whole-body picture of anxiety, helping people recognise these hidden symptoms and gradually settle the system that's producing them.

What actually works

Name the symptom as anxiety, out loud

Simply identifying “this fog/stomach ache/jaw pain is anxiety” reduces the fear-of-the-symptom loop that keeps it going.

Let derealisation pass without fighting it

Trying to “snap out of” derealisation usually intensifies it. Allowing it, while staying gently engaged with your surroundings, lets it fade naturally.

Soften the jaw and shoulders deliberately, without urgency

A few moments of noticing and releasing physical bracing points, without demanding instant relaxation, helps the body register safety.

Rest without guilt

Fatigue from anxiety is real physiological cost. Treating it as a legitimate need for recovery, rather than laziness, speeds the system's return to baseline.

What the research says

The gut and brain are directly linked via the nervous system Chronic stress and anxiety alter gut motility and visceral sensitivity through vagal and hormonal pathways, explaining digestive symptoms common in anxiety. Zaccaro et al., Frontiers in Human Neuroscience, 2018
Slow, controlled breathing reduces physiological arousal A systematic review found slow breathing practices reliably reduce sympathetic nervous system activity, supporting the body-based nature of anxiety symptoms. Zaccaro et al., Frontiers in Human Neuroscience, 2018
Mindfulness-based approaches reduce anxiety symptoms A meta-analytic review found mindfulness-based therapy produced moderate to large reductions in anxiety and depression symptoms across studies. Hofmann et al., Journal of Consulting and Clinical Psychology, 2010

What we resist, we keep in place; what we allow, we move through.
Tara Brach, Radical Acceptance

When to get medical help

Persistent digestive issues, dizziness, or derealisation should still be checked by a GP to rule out other causes. If you experience chest pain, severe breathlessness or fainting, seek urgent care (999/112/911).

Frequently asked questions

Can anxiety cause stomach problems?

Yes. The gut and brain are closely linked, and chronic anxiety commonly produces nausea, cramping or irregular digestion through this connection.

Is derealisation dangerous?

No, though it feels alarming. It's a recognised response to anxiety or overwhelm and typically settles as the underlying anxiety eases.

Why does anxiety make it hard to concentrate?

An alarmed nervous system prioritises scanning for threat over sustained focus, which shows up as brain fog or forgetfulness.

Why am I always tired if I'm anxious, not active?

Chronic low-level alertness is physiologically costly even without physical exertion, which is why anxiety often causes deep fatigue.