So do you need to do an Exercise Tolerance Test? Are they important?
If you’ve been experiencing symptoms such as chest pain, breathlessness or palpitations—especially during physical activity—you may have been referred for something called an exercise tolerance test. But what is it, and what does it tell us about your heart?
As someone who works closely with patients in cardiology, I regularly see how this test helps us understand how the heart performs under physical stress. I’ll explain what an exercise tolerance test involves, when it’s recommended, and what your results might mean.
What Is an Exercise Tolerance Test?
An exercise tolerance test (often abbreviated to ETT) is a common and non-invasive assessment used to evaluate how your heart responds to exertion. It’s sometimes also called a cardiac stress test or treadmill test.
During the test, you’ll walk on a treadmill (or sometimes use a stationary bike) while your heart rate, blood pressure and electrocardiogram (ECG) are monitored. The speed and incline of the treadmill will gradually increase in stages, making your heart work progressively harder.
We’re essentially replicating a situation where your heart is under physical stress to observe how it copes—and to look for any signs of reduced blood flow or abnormal rhythms.
What Does the Test Show?
The exercise tolerance test provides valuable information about:
How well blood is flowing to your heart during activity
Whether you experience chest pain (angina) or shortness of breath with exertion
Any abnormal heart rhythms (arrhythmias) that appear under stress
Your heart rate and blood pressure response to exercise
Overall cardiovascular fitness levels
It’s particularly helpful when investigating symptoms that only appear—or get worse—during activity.
Why Might I Need an Exercise Tolerance Test?
There are several reasons why your doctor or cardiologist might recommend an exercise tolerance test, including:
To assess unexplained chest pain
To investigate shortness of breath or palpitations
To detect underlying coronary artery disease (CAD)
To monitor known heart conditions
To evaluate how well current treatment is working
To assess fitness before surgery or returning to physical activity
It’s also used to risk-stratify patients who have already had a heart event or intervention, such as a stent or bypass.
If you’re unsure whether a test is appropriate for your symptoms, your cardiologist can guide you after an initial consultation.
What Happens During the Test?
The test is usually carried out in a hospital or specialist clinic and takes about 30 to 45 minutes in total.
Here’s what to expect:
Preparation – Electrodes are attached to your chest to record an ECG. A cuff will monitor your blood pressure. You’ll be asked about your symptoms and any medications you’re taking.
Baseline readings – Your heart rate, ECG and blood pressure will be recorded while you're at rest.
The exercise stage – You’ll begin walking on a treadmill at a slow pace. Every few minutes, the treadmill speed and incline will increase. We continue until you reach your target heart rate, experience symptoms, or ask to stop.
Monitoring symptoms – If you feel chest discomfort, dizzy or very short of breath, you’ll be encouraged to stop and rest.
Recovery – After stopping, we’ll continue to monitor you until your heart rate and blood pressure return to normal.
The test is closely supervised throughout, and safety is always the priority.
How Should I Prepare?
Before the test, you may be advised to:
Avoid eating a large meal for at least two hours beforehand
Wear comfortable clothing and shoes suitable for walking
Avoid caffeine, nicotine or alcohol on the day of the test
Check with your doctor if you should pause any medications—particularly beta-blockers, which may affect your heart rate response
If you're unsure, we’ll go over all the preparation details during your booking.
What Do the Results Mean?
Once the test is completed, a cardiologist will analyse your ECG recordings, blood pressure response, and any symptoms you experienced.
The results can indicate:
Normal function – No changes suggest your heart is coping well with exercise
Signs of reduced blood flow – This may suggest coronary artery disease, particularly if you experienced chest pain or ECG changes
Abnormal rhythms (arrhythmias) – Such as atrial fibrillation or ectopic beats that only appear with exercise
Poor exercise tolerance – Which may point to reduced cardiovascular fitness or undiagnosed heart conditions
Sometimes, if results are unclear, further tests may be recommended—such as an echocardiogram, CT coronary angiogram, or 24-hour ECG monitor.
Are There Any Risks?
The exercise tolerance test is considered very safe. It's carried out under close supervision, with medical staff on hand to assist if needed.
You may feel tired or slightly short of breath after the test, but serious complications are extremely rare, especially when the test is done in a clinical setting with experienced staff.
If you're unable to exercise due to mobility or other issues, there are alternative ways to assess heart function—such as pharmacological stress tests, which mimic the effects of exercise with medication.
When Should I Ask About Having This Test?
You should speak to your GP or cardiologist about an exercise tolerance test if you:
Experience chest discomfort or breathlessness during activity
Have risk factors like high cholesterol, high blood pressure, or diabetes
Have a family history of heart disease
Are preparing to return to sport or physical work after a cardiac event
Want a better understanding of your cardiovascular fitness
At Heartsure, we offer full cardiac assessments including exercise ECG testing, echocardiograms, and CT coronary angiograms—all delivered by experienced consultants and support staff in Surrey. If you'd like to explore whether this test is right for you, contact us here. You can also book an appointment using our online tool. Lastly, you can see what some of our current and previous patients say about our clinic here!
Conclusion
The exercise tolerance test is a simple yet powerful way to assess how your heart copes under stress. It helps diagnose heart conditions, measure fitness, and guide treatment decisions, all without invasive procedures.
If you’ve been experiencing symptoms during activity or just want reassurance about your heart health, this test may be the right next step.
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