What's Actually Happening in Your Body (Explained Simply)

What's Actually Happening in Your Body When You Panic (Explained Simply)

No medical jargon. Just a calm explanation of why your nervous system is being so dramatic and why you're not actually dying.

You know the feeling.

You're sitting on the sofa. Watching something utterly unremarkable—Bake Off, maybe, or a repeat of Location, Location, Location. Nothing dramatic. Nothing stressful. And then, from absolutely nowhere, your heart does a little... thing. A flutter. A thud. A beat that feels slightly too hard, slightly too fast.

And your brain, ever the helpful narrator, pipes up: "That's it. That's the one. This is the heart attack. I knew it. I knew we shouldn't have had that second biscuit."

Suddenly you're hyperaware of your own chest. Your breathing goes a bit weird. Your fingers tingle. Your vision does that swimmy thing. And you are now absolutely, one hundred percent convinced that this is it. This is how you go. On the sofa. In your slippers. With a half-empty mug of tea going cold on the side table.

Reader, I have been there. More times than I can count. I've been the woman in A&E at midnight, hooked up to an ECG, absolutely certain my heart was packing it in—only to be told, rather anticlimactically, that my heart was fine. Absolutely fine, actually. It was "just" anxiety.

"Just" anxiety. As if anxiety hasn't got the dramatic range of a West End production.

So let's talk about what's actually happening in your body when panic hits. Because understanding it—really understanding it—takes some of the power away. When you know why your heart is racing, it's slightly less terrifying. Still unpleasant. Still inconvenient. But not "I'm definitely dying" terrifying.

Meet Your Nervous System (It Means Well)

Your body has a built-in alarm system. It's called the sympathetic nervous system, and it's been keeping humans alive for hundreds of thousands of years. Its job is simple: detect danger, sound the alarm, get you ready to run or fight.

Back in the day, danger looked like a sabre-toothed tiger. Or an angry bear. Or a rival tribe member with a large stick. Something external. Something physical. Something you could see.

When the alarm goes off, your body does exactly what it's designed to do:

• Your heart rate increases. Blood pumps faster to your large muscles (legs, arms) so you can run or fight.
• Your breathing quickens. More oxygen in, more carbon dioxide out. Fuel for the muscles.
• Blood diverts away from non-essential functions. Digestion? Paused. Rational thought? Downgraded. Saliva production? Not a priority.
• Your senses sharpen. You're hyperaware. Scanning for threats.
• Adrenaline and cortisol flood your system. You are primed. Ready. A lean, mean, tiger-fighting machine.

This system is brilliant. It's efficient. It's fast. It has saved countless human lives.

The problem is, there is no tiger.

There's just you. On the sofa. Watching Bake Off. And your brain has decided, for reasons it's not legally obligated to explain, that now is the time to sound the alarm. Full volume. All stations. This is not a drill.

Why Does It Feel Like a Heart Attack?

This is the question I asked the very patient A&E doctor at midnight while trying not to cry. And his answer was surprisingly simple: because the symptoms overlap. A lot.

Symptom	Panic Attack	Heart Attack
Chest pain or tightness	✅ Common	✅ Common
Racing or pounding heart	✅ Very common	✅ Common
Shortness of breath	✅ Common	✅ Common
Sweating	✅ Common	✅ Common
Nausea	✅ Common	✅ Can occur
Tingling in hands/arms	✅ Common	✅ Can occur
Sense of impending doom	✅ Hallmark symptom	✅ Can occur

 

See the problem? Even medical professionals sometimes struggle to tell the difference without an ECG. So please—if you're genuinely unsure, if this feels different from your usual panic, if you have risk factors for heart issues—get checked. The nice people at 111 or 999 would rather you called and it was "just" anxiety than you didn't call and it wasn't.

But if you've been checked—if you've had the ECG, the blood tests, the reassuring chat with a doctor who says your heart is "absolutely fine, actually"—then you can start to trust that what you're experiencing is a false alarm. A very loud, very physical, utterly convincing false alarm.

Why Do I Feel Like I Can't Breathe?

This one's particularly cruel. You feel like you're suffocating. Like you can't get enough air. Like you need to take a massive, deep breath right now or you might actually pass out.

Here's the counterintuitive truth: you have too much oxygen, not too little.

When you panic, you breathe faster. You exhale too much carbon dioxide. Carbon dioxide helps regulate blood flow to the brain and maintains the pH balance of your blood. When CO2 drops too low, your blood vessels constrict. Less blood gets to your brain. You feel dizzy, lightheaded, tingly.

Taking a massive deep breath makes it worse. You're adding even more oxygen and blowing off even more CO2.

What actually helps: Focus on the exhale. Make it longer than the inhale. Breathe in gently for 4 seconds. Breathe out slowly—through pursed lips, like blowing on hot soup—for 6 or 7 seconds. This builds CO2 back up, dilates blood vessels, and signals to your nervous system that the emergency is over.

Why Do My Hands and Face Go Tingly?

This is another CO2 thing. When you hyperventilate, the drop in carbon dioxide causes temporary changes in blood chemistry. Calcium ions shift around. Nerves get a bit twitchy. The result? Tingling, numbness, or that weird "pins and needles" sensation in your hands, feet, and around your mouth.

It's uncomfortable. It's alarming. It's not dangerous. It resolves on its own as your breathing returns to normal.

Why Does Everything Feel Unreal?

This one scared me more than the heart stuff, the first time it happened. I was standing in my own kitchen, looking at my own hands, and they didn't feel like my hands. The room looked wrong. Familiar objects seemed strange. I felt like I was watching myself from a distance, or like there was a sheet of glass between me and reality.

This is called derealisation (when the world feels unreal) or depersonalisation (when you feel unreal). It's incredibly common during panic attacks. It's also incredibly unsettling.

Here's what it actually is: your brain's natural anaesthetic. When stress levels hit a certain threshold, the brain can dial down emotional processing to protect you from overwhelm. It's a dimmer switch on reality. A temporary, reversible, completely harmless dimmer switch.

It passes. It always passes. It doesn't mean you're losing your mind. It doesn't mean you're developing psychosis. It's just your brain saying, "This is a bit much. I'm going to step back for a moment."

So What Do I Do With All This Information?

Knowing what's happening doesn't stop the panic. I wish it did. But it does something almost as important: it stops you adding a second layer of fear on top of the first.

The first layer is the physical sensations. The racing heart. The tight chest. The dizziness.

The second layer is the fear about those sensations. "What if this is a heart attack? What if I'm dying? What if I'm losing my mind?"

When you understand that a racing heart is just adrenaline, that dizziness is just a CO2 imbalance, that derealisation is just a temporary brain dimmer switch—you can short-circuit that second layer. You can say, "Oh. Right. This again. I know what this is. It's uncomfortable, but it's not dangerous."

And that tiny shift? That "oh, this again"? It's the beginning of taking the power back.

A Final Thing

The next time your heart does that little flutter. The next time your brain pipes up with "This is it, we're dying."

Remember: your nervous system is not your enemy. It's an overenthusiastic bodyguard who's had too much coffee and is seeing threats everywhere. It means well. It's just a bit... extra.

You're not dying. You're having a panic attack. And it will pass. It always does.

Anxiously Ever After is written by me, Jennie, a 50-something-year-old woman with lifelong anxiety and diagnosed GAD. She's been to A&E, had the ECG, and lived to write about it.