Why Being Ill Can Make Anxiety Feel So Much Worse

That time of year has arrived again.

Tissues everywhere. Everyone sniffling and sneezing. Someone stands next to you and coughs, and your brain immediately goes, 'Right… that tickle in my throat...that’ll be me catching whatever they have.'

If you already live with anxiety, being ill - or even the idea of getting ill - can feel like petrol being poured onto a fire. Your body feels off, your brain goes on high alert and suddenly everything feels harder.

This anxiety that shows up can not only spark a spiral of negative thoughts, but it can actually have a negative effect on your immune system too ( which plays into more anxiety, and before you know it you’re in a vicious cycle).

In today’s blog I’ll be sharing the neuroscience behind why illness and anxiety so often show up together.

The Brain, Stress and Your Immune System

When you feel anxious or stressed, your brain switches into what we often call threat mode. This is your survival system - designed to keep you alive - stepping in. It’s brilliant if you need to react quickly to potential danger. Not so great when it switches on constantly for appaeante reason or stays switched on for weeks or months.

This stress response is controlled by a communication pathway called the HPA axis (the hypothalamic‑pituitary‑adrenal axis). When it’s activated, your body releases cortisol, our main stress hormone.

Cortisol is helpful in short bursts. It helps manage inflammation and gives you energy to cope. But when cortisol stays high for long periods (as it often does with chronic stress or anxiety), it starts to wreck havoc on your immune system.

Think of your immune system like a security team.

Stress hormones are like constant false alarms pulling the guards away from their posts. Eventually, they’re exhausted, understaffed, and slower to respond when a real threat - like a virus - comes along.

In fact, research shows that prolonged stress and anxiety can suppress parts of the immune response, alter how immune cells behave, and increase overall inflammation in the body. So this makes us more vulnerable to infections such as colds and flu.

Acute Stress vs Chronic Stress

Here’s where it gets interesting...

Short‑term stress – the kind that comes and goes – can actually boost certain immune responses temporarily. It helps immune cells move quickly to where they’re needed.

But chronic stress (from ongoing anxiety, constant worry or emotional overload) has the opposite effect.

Studies consistently show that long‑term stress weakens immune efficiency, disrupts inflammatory signalling and increases susceptibility to illness. It’s a bit like revving your car engine constantly. You might get a quick burst of power but eventually something will wear out.

What Actually Changes in the Body?

When anxiety and stress are ongoing, we can measure real physical changes, including:

• Reduced Natural Killer (NK) cell activity:

  These are frontline immune cells that help fight viruses. Anxiety and poor sleep have been linked to reduced NK cell function.

• Lower antibody responses:

  Chronic stress has been shown to blunt antibody production, meaning the immune system may not respond as effectively to infections.

• Increased inflammatory signals:

  Instead of a balanced response, the immune system can become dysregulated, which then has an impact on our mood, energy and sleep.

How Immune Chemicals Affect Your Mood and Anxiety

On top of all this, your immune system doesn’t work quietly in the background. It talks to your brain.

When your body detects infection, stress, or ongoing strain, it releases tiny chemical messengers called cytokines. Their job is to coordinate an immune response, telling cells when to fight, rest or repair.

The important part?


Cytokines can cross the blood–brain barrier and directly influence brain chemistry.

Think of cytokines like group messages sent from your immune system to your brain saying, 'Something’s not right! Stay alert.'

When cytokine levels rise (which happens during illness, inflammation, chronic stress or poor sleep), they can:

• Reduce the availability of mood-regulating neurotransmitters like serotonin and dopamine

• Increase activity in brain areas linked to threat detection and worry

• Make the nervous system more sensitive and reactive

This is why, when you’re ill or run down, you might feel:

• More anxious for no obvious reason

• Lower in mood or emotionally flat

• Tearful, irritable or mentally foggy

• Less able to cope with things that normally feel manageable

  
  

Researchers sometimes call this ‘sickness behaviour'.

It’s the body’s way of encouraging rest and recovery. But if anxiety is already part of your life, this biological shift can feel overwhelming and frightening rather than protective.

Why It Turns Into a Loop So Easily

When anxiety increases, sleep often suffers.


When sleep suffers, inflammation rises.


When inflammation rises, cytokine levels increase.


And when cytokines influence the brain, anxiety and low mood intensify.

And this loop goes round and round.

Understanding this loop can be incredibly validating.
 Because it’s not you failing to cope and being ‘weak.’
 It’s a sign your nervous system is overloaded and it’s doing its best to protect you.

Health Anxiety

For some people, illness doesn’t just feel uncomfortable - it's highly stressful and feels dangerous.

A sore throat becomes 'What if this is something serious?'

A lingering cough turns into hours of checking symptoms.

This is health anxiety and it’s driven by a brain that’s trying desperately to keep you safe.

I won’t go into too much detail here, because health anxiety deserves its own space (and I’ll be dedicating a full blog to this in the new year), but it’s important to know that this response is rooted in neurobiology, not imagination or attention‑seeking.

'Just Don’t Stress' (If Only It Worked Like That)

Let’s be honest, being told ‘just relax’ when you’re anxious or unwell is rarely helpful. (Face palm!) If calming your mind were as simple as deciding to, I'm 100% sure that you would have done it already.

This is where Solution Focused Hypnotherapy can make a real difference.

How Solution Focused Hypnotherapy Can Help

Solution Focused Hypnotherapy works with the brain and nervous system to:

• Reduce the constant activation of the stress response

• Lower cortisol levels over time

• Improve sleep quality and emotional regulation

• Calm health‑related anxiety and symptom hyper‑focus

• Support resilience so illness doesn’t trigger an anxiety spiral

  
  

By helping your brain step out of survival mode, your body can redirect energy back into healing, immunity and balance.

If you notice your anxiety spikes when you’re ill - especially during cold and flu season - you’re not imagining it, and you’re not alone. Your mind and body are deeply connected, and at this time of year that connection can feel louder than ever.

If anxiety is taking a toll on your sleep, mood or immunity, support is available.

If you would like to find out more about how Solution Focused Hypnotherapy can help you feel calmer, more resilient and better equipped to cope, you’re very welcome to get in touch.

Click to get in touch