An ECG — an electrocardiogram — is one of the oldest tests in medicine and still one of the most useful. It is also one of the least understood by the people having it, largely because it takes so little time that it can feel like it cannot have told anyone much.

What it actually measures

Every heartbeat starts as an electrical signal that travels through the heart muscle in a set sequence and makes it contract. That electrical activity is detectable at the skin. An ECG places electrodes on the chest, arms and legs and records the signal from several angles at once, producing the familiar tracing.

Nothing is sent into you. The machine only listens.

What it can show

• Rhythm. Whether the heart is beating regularly, too fast, too slowly, or irregularly. Atrial fibrillation is often picked up this way, sometimes in someone who had no idea.
• Signs of strain or thickening of the heart muscle, which can reflect long-standing high blood pressure.
• Evidence of a past heart attack, sometimes one the person did not know they had had.
• Changes suggesting the heart muscle is not getting enough blood, which is why an ECG is done early when someone has chest pain.
• Conduction problems — delays or blocks in the electrical pathway.
• Effects of some medicines and electrolyte problems, which can alter the tracing in recognisable ways.

What it cannot show

This is the important half, and it is the part that gets glossed over.

A normal ECG does not mean your heart is fine. It records what was happening in those few seconds while you were lying still. Someone with significant narrowing of the coronary arteries can have a completely normal resting ECG, because the problem only declares itself under load. That is why an exercise stress test, a scan, or blood tests are sometimes the next step.

It also does not directly show the valves, or the pumping strength of the heart — an echocardiogram does that.

So an ECG is one piece of information, read alongside your symptoms, your history, your blood pressure and often blood tests. Your doctor is interpreting the whole picture, not the tracing on its own.

What to expect on the day

1. You will be asked to remove clothing from the upper body and lie down. A gown or sheet is provided, and you can ask for a chaperone at any point.
2. Ten sticky electrodes are placed — six across the chest, one on each arm and leg. Some chest hair may need trimming for them to stick.
3. You lie still and breathe normally for about ten seconds while the recording is taken. Talking, shivering or moving adds interference, so it is worth being still.
4. The electrodes come off, and that is it.

The whole thing usually takes a few minutes. It does not hurt. There is no radiation, no injection, no preparation and no fasting.

Because it is done here rather than referred out, your doctor reads it in the same visit and talks you through it while you are still in the room. If it needs to go to a cardiologist, it goes with the referral.

When one might be suggested

Common reasons include chest discomfort, palpitations or a sense that the heart is racing or skipping, breathlessness, dizziness or fainting, a heart murmur, monitoring of blood pressure or heart medicines, before some surgery, and as part of some workplace assessments.

The one thing that cannot wait

If you are having chest pain, tightness or pressure now — especially with sweating, nausea, breathlessness, or pain spreading to the arm, neck or jaw — call 000. Do not drive yourself and do not book an appointment for later in the week. Ambulance crews carry ECG machines and can begin treatment on the way.

General information only. This article is general health information for anyone who finds it useful. It is not advice about your own situation and it does not replace a consultation with a doctor who knows you. If you are worried about a symptom, book an appointment or call us on (02) 6530 7404. Last reviewed 14 July 2026.

Spirometry is the standard test of how well your lungs move air. It is used to help diagnose asthma and chronic obstructive pulmonary disease, to track them over time, and to monitor people whose work exposes them to dust — which, in this part of the state, is a great many people.

It is also the test people most often feel they have done badly, because unlike most tests, this one asks something of you.

What it measures

You take the deepest breath you can, seal your lips around a mouthpiece, and blow out as hard and as fast as you possibly can, then keep going until there is nothing left. The machine records the volume and the speed.

Three numbers do most of the work:

• FVC — forced vital capacity. The total volume you can blow out after a full breath in.
• FEV1 — the volume you blow out in the first second. This is the one that drops when airways are narrowed.
• The ratio between them. This is the one that matters most. A low FEV1/FVC ratio — a small first second relative to the total — points towards obstruction, narrowed airways, as in asthma or COPD. If both numbers are reduced but the ratio is preserved, that can suggest restriction, where the lungs cannot fully expand — but spirometry cannot confirm that on its own, and further lung volume testing is needed.

Your results are compared with predicted values for someone of your age, height, sex and ethnicity, because a healthy 25-year-old and a healthy 65-year-old should not be expected to produce the same figures.

Why you get asked to do it again

Spirometry is effort-dependent. If you do not take a full breath in, or you do not blow hard from the very start, or you stop early, the numbers come out low — and low numbers that are caused by technique look uncomfortably like low numbers caused by disease.

So you will be coached loudly and enthusiastically, and asked to repeat it until several attempts agree. Usually that is three good efforts. It is tiring and slightly undignified, and it is the only way to get a result worth acting on.

Some people feel lightheaded or cough afterwards. Both settle quickly.

Reversibility testing

Sometimes the test is done, then a reliever inhaler is given, and after about fifteen minutes the test is repeated. If the numbers improve substantially, that tells us the narrowing is reversible — a pattern typical of asthma. If they do not shift much, that points more towards fixed obstruction, as in COPD.

This is why the appointment can take longer than people expect. Allow the time.

How to prepare

• Ask about your inhalers when you book. For some tests you will be asked to withhold them for a set number of hours; for others you should take them as normal. It depends why the test is being done, so do not guess.
• Avoid a large meal in the hour or two beforehand.
• Avoid vigorous exercise beforehand.
• Do not smoke or vape on the day if you can manage it — at minimum, not in the hour before.
• Wear something that does not restrict your chest or waist.
• Bring your inhalers with you, and mention any dust, smoke or chemical exposure at work.

Tell us beforehand if you have had recent chest, abdominal or eye surgery, a recent heart attack or a collapsed lung — spirometry involves real pressure and there are times it should be deferred. Tell us if you are pregnant as well, so the test can be tailored.

What the result means

A single spirometry result is not a diagnosis on its own. It is read alongside your symptoms, your history, your exposures and your examination. A normal result in someone with a convincing story may simply mean their airways were behaving on the day, which is common in asthma.

Where it becomes most valuable is over time. A series of results across years shows the direction of travel far more clearly than any one test — which is exactly why dust-exposed workers are monitored with it rather than tested once.

If you work around dust or smoke, it is worth reading about smoke, dust and your lungs as well.

General information only. This article is general health information for anyone who finds it useful. It is not advice about your own situation and it does not replace a consultation with a doctor who knows you. If you are worried about a symptom, book an appointment or call us on (02) 6530 7404. Last reviewed 7 July 2026.