Some heart problems only show up when the heart is working hard. A stress test pushes your heart in a safe, controlled way so your healthcare team can see how it copes.
Imagine getting a tight feeling in your chest every time you walk up the hill to the bus stop, which eases when you stop. At rest, your ECG is normal. A stress test shows what happens on the hill.
What a stress test is
A cardiac stress test checks how your heart works during physical stress. The most common reason is to look for coronary heart disease, where narrowed arteries reduce blood flow to the heart muscle. This may not cause problems at rest, but can show up when the heart needs more oxygen.,Stress tests are also used to assess exercise capacity, check heart rhythm during exercise, and guide treatment after a heart attack or before major surgery.
Types of stress test
- Exercise ECG (treadmill test): you walk on a treadmill or ride an exercise bike while your ECG, heart rate and blood pressure are recorded
- Stress echocardiogram: ultrasound pictures of the heart before and after exercise, or during medicine that makes the heart work harder
- Nuclear perfusion scan (myocardial perfusion imaging): a small amount of radioactive tracer shows blood flow to the heart muscle at rest and under stress
- Stress cardiac MRI: an MRI scan during medicine that increases blood flow
How to prepare
- Wear comfortable clothes and trainers or walking shoes
- Avoid a heavy meal for a few hours before
- You may be asked to avoid caffeine (coffee, tea, cola, chocolate) for 24 hours before some tests, as it interferes with certain medicines used
- Ask whether to stop medicines such as beta-blockers beforehand; do not stop them unless told to
- Bring your inhalers if you have asthma, and a list of your medicines
What happens during an exercise test
Electrodes are placed on your chest, and a blood pressure cuff on your arm. You start walking slowly on the treadmill. Every few minutes, the speed and slope increase. The team watches your ECG, blood pressure and symptoms throughout.,The test continues until you reach a target heart rate, become too tired, develop symptoms or the team sees changes that mean it should stop. Most people exercise for 6 to 12 minutes. Afterwards, you are monitored while your heart rate returns to normal.
If you cannot exercise
If arthritis, lung disease or other conditions stop you exercising, a medicine-based stress test may be used instead. Medicines such as dobutamine make the heart beat faster and harder, while others such as adenosine or regadenoson widen the arteries. These can cause temporary flushing, breathlessness, a headache or chest tightness, which usually pass quickly.
Tell the team immediately if you feel
- Chest pain, pressure or tightness
- Severe breathlessness
- Dizziness or light-headedness
- Palpitations
- Pain in your legs that stops you continuing
Risks
Stress tests are generally safe because they are carefully supervised by trained staff with emergency equipment available. There is a small risk of an abnormal heart rhythm, a fall in blood pressure or, very rarely, a heart attack. The team will discuss any risks that apply to you before the test.
Understanding your results
A normal result means your heart showed no signs of reduced blood flow at the level of exercise you reached. This is reassuring, though it does not completely rule out heart disease.,An abnormal result might show ECG changes, symptoms, a drop in blood pressure or areas of heart muscle not getting enough blood. You may need further tests, such as a CT coronary angiogram or invasive coronary angiogram, and treatment with medicines, stents or bypass surgery.
What happens after an abnormal result
Your healthcare provider will look at the whole picture: your symptoms, the type of changes seen on the test and your other risk factors. You may be started on medicines to relieve angina and protect your heart, such as aspirin, a statin, a beta-blocker and a short-acting nitrate spray to use if pain comes on.
You may then be offered further tests to see the arteries directly, such as a CT coronary angiogram or invasive angiogram, to decide whether a stent or bypass surgery would help.
Improving your fitness safely
Whatever your result, regular physical activity is one of the best things you can do for your heart. If you have heart disease, ask your healthcare team or a cardiac rehabilitation service for advice on how to exercise safely. Most people can gradually build up to at least 150 minutes of moderate activity each week, such as brisk walking.
Questions to ask
- How long did I exercise for, and was that normal for my age?
- Did my ECG or blood pressure change?
- Do I need any medicines now?
- Do I need further tests?
Frequently asked questions
How long does the whole appointment take?
An exercise ECG usually takes about an hour. Nuclear scans can take several hours, sometimes over two days.
Can I drive home?
Usually yes after an exercise ECG. Ask if you have had sedation or specific medicines.
Is the radiation from a nuclear scan safe?
The dose is small. Tell the team if you are pregnant or breastfeeding.
But what if I cannot finish the test?
Tell the team. Stopping early still provides useful information, and medicine-based tests are available if exercise is not possible.
Your next step: Before your test, check the instructions about caffeine and medicines, and ask any questions you have.
Related: Angina: chest pain warning signs · Echocardiogram
Sources: British Heart Foundation, American Heart Association, European Society of Cardiology chronic coronary syndromes guidelines, National Institute for Health and Care Excellence.
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