On a Saturday morning about five months ago, I found myself hooked up to an ECG machine.

I remember feeling equal parts stressed and relieved as I lay on the flimsy, plastic-covered vinyl mattress, the nurse gently placing electrode patches across my chest, wrists and ankles.

Stressed, because I was heading overseas the following day, and had an important to-do list of 375 Very Important Tasks.

Relieved, because I had been experiencing chest pain for weeks, and if I was on the brink of a heart attack, this would surely give my doctor an indication that something was wrong.

"Just breathe normally," the nurse reassured me as she tapped away at a machine that looked like it was from the '90s.

The ECG — or electrocardiogram — was inside the pathologist's office of my GP, measuring my heart's electrical activity. The routine test, often used by health professionals to investigate chest pain or breathlessness, detects cardiovascular abnormalities.

This was my second ECG in a week. The first, a couple of days earlier, had indicated a slight 'we're-not-too-worried-but-we-should-probably-double-check-it' irregularity. So, my GP ordered a second.

This time, when the test was finished, the doctor on-call checked my results, and sent them to a cardiologist to review.

"All clear," she smiled as she handed me some paperwork in the waiting room.

"If you feel short of breath or sudden pressure, tightness or pain in your chest, go to the emergency."

I was relieved. There was no physical problem. I had the reassurance I needed.

Still, I half-joked with a friend later that day that I hoped a medical doctor would be onboard the 21-hour flight I was set to take the following morning.

He laughed, told me not to worry, and said he'd experienced similar chest pain a few years ago that "just turned out to be stress".

A lightbulb went off in my head.

I couldn't have stressed myself to the point of physical pain — could I?

Anxiety in the ED

A month or so after I returned from overseas, I went back to my GP and told her my chest pain had all but disappeared. I also mentioned the conversation I'd had with my friend.

"Is that … possible?" I asked, timidly, "to experience chest pain because of anxiety or stress?"

"Absolutely," she nodded.

I was stunned. I read and write about health for a living and am familiar with the physical impacts of mental illness. I've experienced anxiety throughout my life, and suffered panic attacks in my early 20s.

But pain in my chest because of pain in my brain? I was surprised.

"It's fairly common," according to Simon Judkins, emergency medicine physician and president of the Australian College for Emergency Medicine.

"We see quite a few people ending up in the emergency department concerned about symptoms which ultimately can be related to anxiety."

If you are in any doubt, and you have pain in your chest, call triple zero (000) immediately and ask for an ambulance.

Figures vary, but it's estimated more than 40 per cent of patients admitted to emergency departments with chest pain receive a 'non-cardiac' diagnosis. Research shows ED providers estimate 30 per cent of patients seeking emergency care for chest pain have anxiety as a primary problem.

"There's quite a few 'cardiac-type' symptoms that people can present with … anything from chest and back pain to heart palpitations and feelings of shortness of breath," Dr Judkins said.

'The worst thing we can do'

It's a complicated and challenging issue for health professionals and patients alike.

"Cardiac-type" symptoms can indicate a serious medical emergency, and should never be ignored. It's what sends people to the ED in the first place.

"If we don't do the right investigations for patients to ensure there isn't some underlying pathology, then we're likely to miss things," Dr Judkins said.

Physical symptoms, such as chest pain — even when there is no underlying cardiac cause — can be understandably very frightening.

"The worst thing we can do … is just sort of pat people on the back and say, 'look, it's just anxiety'. That certainly doesn't help, and can make things worse," Dr Judkins said.

Then there's the problem of dismissing or misdiagnosing people with mental illness.

"We know, for example, that patients with anxiety and panic disorders — when they do have physical pathology … often the physical issues get missed," Dr Judkins said.

"People tend to label it as 'it's just your anxiety' or 'it's just the mental health issues you've got that are manifesting'."

EDs in Australia are stretched as it is when it comes to patients with acute mental health problems. For many people, the emergency is their only option — or their last resort.

The gender factor

It's a gendered issue too. Research shows young women who report heart attack symptoms are more likely to dismiss those symptoms as not heart related — as are their clinicians — when compared to men.

We also know women, who are more prone to anxiety, are less likely to receive treatment for cardiovascular disease and more likely to experience poorer outcomes.

All of this is to say: you should never ignore symptoms of a heart attack or stroke, even if you are in doubt, or if you think they might be related to your mental health.

For people with anxiety or panic disorders, however, it can be helpful (at least it was for me) to understand how psychological distress can manifest physically, in seemingly unexpected ways.

How stress puts your body into overdrive

Anxiety is our body's natural response to stress — internal or external.

In the face of a perceived threat, our brain releases adrenaline and cortisol to kick-start the "fight or flight" response, says Eileen Stech, psychologist and PhD candidate at the University of New South Wales.

"That adrenaline brings on a whole cascade of changes where really everything in our body either down-regulates or up-regulates to try and survive," Ms Stech said.

That means our heart and breathing rates increase (to move more oxygen around our body), our muscles become tense, and blood flow is diverted away our abdominal organs to our brain.

Our fight or flight response help us effectively deal with threats. But in some cases, it's triggered inappropriately.

When this happens, our response to stress can tip over into a brief, intense burst of acute anxiety — a panic attack.

"That's when you have that really sudden rush of intense symptoms like sweating, a racing heart, dizziness, nausea, and shortness of breath," Ms Stech said.

Rapid breathing can lead to hypoventilation, which can cause shortness of breath as well as a contraction of blood vessels, which may result in chest pain.

For many people, panic attacks can occur during times of acute stress at work or home. But they can also happen unexpectedly, and in seemingly stress-free situations as a result of ongoing anxiety or stress.

It's estimated up to 30 per cent of Australians will experience a panic attack at some point in their life; a smaller per cent — approximately three in every 100 people — will go on to develop panic disorder, which is when panic attacks become recurrent and disabling.

"What we see in panic disorder is people become really afraid about what those panicky feelings mean, and they can often misinterpret them as [symptoms of] a heart attack or a stroke," Ms Stech said.

In Australia, one in three women will experience anxiety. Among men, the rate is one in five. ( Pixabay )

"Often people will actually present to the emergency department several times before it's identified that ... psychological intervention would be most effective."

While the physical signs of anxiety are often most apparent in people who have panic attacks or panic disorder, almost everyone with anxiety — and often people who are chronically stressed — will experience some type of physical response.

Long-term health impacts

With the exception of some extremely rare conditions, anxiety and acute stress in the short-term is very safe, says senior psychology lecturer Philippe Gilchrist of Macquarie University.

"In the context of evolution, it helps us face a predator or an acute threat," he said.

"But our body is not as well equipped to face the types of chronic stresses that we're dealing with today.

"It's almost like you're putting your body in overdrive too often. It's not built to do that."

Since our bodies are not designed to always be 'on alert', being in a near-constant state of 'flight or fight' can have significant impacts on our physical health, says Justin Kenardy, professor of clinical psychology at the University of Queensland.

"If you've got chronic stress, those [stress response] symptoms continue … and those kinds of things over time tend to take a toll on the physical function of the body," he said.

Common symptoms of anxiety include chest pain, headaches, digestive troubles, nausea, sleep problems, weakness, fatigue, and muscle tension.

"The difficulty is you get these kind of symptoms and you don't necessarily recognise them as being indicators of stress and anxiety," Professor Kenardy said.

Anxiety has been implicated in several chronic illnesses, including respiratory disorders and gastrointestinal conditions. One of its most concerning potential long-term impacts is on the heart.

While the link between stress and cardiovascular disease is known, the mechanism through which stress actually affects the heart is not well understood.

A study published in The Lancet medical journal in 2017 was the first to establish a link between activity in the amygdala (the brain region involved in stress) and subsequent cardiovascular events.

"The nail has never really been solid in the coffin to say stress links in a casual manner to cardiovascular disease," Dr Gilchrist explained.

"But it now seems there's a compelling argument that we should be assessing stress as a marker for risk for cardiovascular disease."

According to Dr Gilchrist, whose research focuses on the mechanisms of stress-related cardiovascular responses, "a lot could be said" now about the importance of stress on heart health, even compared to just a couple of years ago.

"No medical practitioner could ignore the role and the likely biological mechanisms of stress impacting the heart anymore," he said.

"It's amazing how much the mind can influence the heart, and conversely, how the activity of the heart can prime emotions or different ways of thinking. The relationship is bidirectional."

It's a sign

Professor Kenardy said physical symptoms of stress were usually an indication people needed to "check in" with themselves about what was going on in their life.

"It's a sign they need to take care of themselves, and look at how they're reacting and responding to their stress," he said.

Finding myself at the GP on a Saturday morning to check I wasn't on the brink of a heart attack was a sign — one of many — I needed to slow down.

It can be easy to minimise or dismiss even the most serious symptoms out of fear we're over-reacting, or, worse, won't be taken seriously.

But if you're in any doubt, and you experience pain in your chest (or other heart attack symptoms), you should never hesitate to call 000 or visit the ED.

