When Should I Do an Exercise Tolerance Test?

Aug 9

5 min read

Many people first hear the term exercise tolerance test (or ETT) when a doctor suggests one during a heart health check. If you’ve been referred for an ETT, or you’re just curious about what it involves, it’s normal to have questions. What actually is the test? Is it safe? Do I need to train for it? And what happens if I can’t manage exercise?

Let’s break it down clearly.

What Is an Exercise Tolerance Test?

An exercise tolerance test is a common heart test used to assess how your heart performs under physical stress. In short, it shows how well your heart works when it’s beating faster, usually during exercise.

The test is most often done on a treadmill, though sometimes a stationary bike is used instead. It’s supervised by trained staff who carefully monitor your heart rate, blood pressure and ECG (electrocardiogram) as you move.

It’s often referred to as a treadmill test or cardiac stress test, and it can help diagnose coronary artery disease, abnormal heart rhythms, and even guide treatment decisions for those with known heart problems.

Why Would I Need One?

There are several reasons a cardiologist might recommend an ETT:

You’ve experienced chest pain, shortness of breath, or heart palpitations
Your doctor wants to investigate possible coronary artery disease
You’ve had an abnormal ECG and need further testing
You’re being monitored for known heart conditions
You need medical clearance for certain jobs or driving licences (such as Group 2 HGV licences)
You have a family history of heart disease and want a more detailed assessment

How Is the Test Done?

If you're having the test through the NHS, it’s typically done on a treadmill in a hospital setting. The treadmill gradually increases in speed and incline over three-minute stages while your heart is monitored using ECG leads attached to your chest.

In private clinics, the process is largely the same, though you may experience shorter wait times and access to more modern equipment. Some clinics offer bike-based ETTs, which are sometimes preferred for patients with joint issues.

Here’s what to expect on the day:

You’ll be asked to avoid heavy meals, caffeine, and smoking before the test.
You’ll change into loose, comfortable clothing and have ECG leads attached.
A baseline ECG is taken while you rest.
You’ll start walking on the treadmill or cycling at a gentle pace.
Every 3 minutes, the intensity increases.
The test stops if you experience symptoms, reach target heart rate, or if the doctor sees clear test results.
You’ll then cool down and be monitored briefly before going home.

What If I Can’t Exercise?

If you’re unable to walk or cycle due to disability, injury, or other physical limitations, don’t worry. UK hospitals offer alternative tests such as:

Pharmacological stress tests – where medication is used to simulate the effect of exercise on the heart.
Stress echocardiograms – combining ultrasound and medication to assess function.
Nuclear medicine scans – using a small amount of tracer to assess blood flow.

These are all available on the NHS and in private care. The method chosen will depend on your health and mobility, but the goal is the same: assess how well your heart handles strain.

What Does an ETT Show?

An exercise tolerance test gives cardiologists useful information about how your heart behaves under pressure. It helps answer questions like:

Is your heart receiving enough oxygen during effort?
Are there irregular heart rhythms brought on by exercise?
Are there early signs of blocked or narrowed arteries?
Is your current treatment plan (such as statins or blood pressure meds) working?

It also helps predict future risk and guide decisions about whether further testing (like an angiogram or scan) is needed.

How Much Does It Cost?

Through the NHS, ETTs are free, but you’ll need a referral from your GP or consultant. Waiting times vary based on location and urgency but can range from 2 to 8 weeks.

Private costs range between £250 and £500 depending on the clinic, location, and whether additional imaging is included. Some people choose private for quicker access, particularly if they’re asymptomatic but concerned due to family history or job requirements.

What Are the Different Types of ETT?

While the treadmill version is most common, the bike-based test is occasionally used for people with mobility or joint issues. Other versions include:

Stress echocardiograms (exercise + ultrasound)
Myocardial perfusion scans (exercise + radioactive tracer)
Pharmacological ETTs (no physical activity – uses medication)

What Are the Risks or Limitations?

ETTs are generally safe. In the UK, all tests follow strict protocols set out by the NHS and British Cardiovascular Society to ensure safety and accuracy.

However, ETTs can sometimes give false positives (suggesting a problem when there isn’t one) or false negatives (missing signs of disease). That’s why doctors look at ETT results alongside your symptoms, history, and other test findings.

During the test, your vitals are monitored closely. In the rare event of a heart-related event like arrhythmia or chest pain, the test will be stopped immediately, and emergency equipment is always on hand.

What If I’m Fit and Healthy, Do I Still Need One?

Even people with no obvious symptoms might be advised to have an ETT, particularly if:

You have a strong family history of heart disease
You’re applying for a driving or aviation licence
You’re starting an intense fitness regime after a long period of inactivity
You’ve had borderline results on other tests (like ECG or cholesterol)

It’s not a routine screening tool for everyone, but in the right context, it can give very useful insights.

Is the ETT Still Used, or Is It Being Replaced?

Some hospitals are moving towards more advanced imaging tests like CT angiography or cardiac MRI, especially where more accuracy is needed. But the ETT remains widely used particularly in NHS outpatient clinics and private cardiology practices as an initial assessment tool.

It’s non-invasive, cost-effective, and gives real-time feedback on how the heart performs during stress. In fact, many treatment plans (like stent decisions or medication adjustments) still start with ETT results.

How Do Waiting Times Compare Between NHS and Private Clinics?

Waiting times can be a big factor when deciding where to have your ETT. On the NHS, referrals typically come from your GP or cardiologist, and waits can vary widely depending on your location, hospital trust, and how urgent your case is. In many areas, you might wait anywhere from 2 to 12 weeks for a routine test, though emergency cases are prioritised and can happen much sooner.

Private clinics in the UK often offer much faster access sometimes within days or a week making them a popular choice if you're anxious about symptoms or need quick results for work or travel. However, this comes at a cost, and it's worth checking with your insurance provider if they cover it. Regional differences play a role too; for example, waits might be longer in busy urban NHS trusts like those in London compared to rural areas.

Final Thoughts

The exercise tolerance test is a well-established way to assess how your heart performs under stress. Whether you’re experiencing symptoms, have risk factors, or need clearance for a licence, the ETT offers valuable information without the need for invasive procedures.

At Heartsure, we help guide patients through their testing options whether via the NHS or privately. If you’re unsure whether an ETT is right for you, or if you’ve been advised to have one and want to know what to expect, we’re here to help. Get in touch with us here or book an appointment online here.

If you’ve noticed changes in your energy levels, chest sensations, or simply want clarity about your heart’s performance, an exercise tolerance test could be the right next step.