Cardiac Stress Test
Exercise Stress Testing
A supervised treadmill test that challenges the heart under controlled exertion — revealing ischaemia, arrhythmias, and abnormal blood pressure responses that are invisible at rest.
The Test
What Is an Exercise Stress Test?
An exercise stress test (also called an exercise tolerance test or ETT) records the heart's response to progressive physical exertion. You walk on a treadmill that gradually increases in speed and incline every three minutes while a 12-lead ECG, your blood pressure, and your symptoms are monitored continuously throughout.
The principle is straightforward: coronary artery narrowings that do not restrict blood flow at rest may become significantly limiting when the heart has to work harder. Increasing demand unmasks ischaemia — producing characteristic ST changes on the ECG, chest symptoms, or an abnormal blood pressure response — that a resting ECG would never detect.
The test also provides valuable prognostic information. How long you exercise, the maximum workload you achieve (measured in metabolic equivalents, METs), your heart rate and blood pressure recovery, and whether any arrhythmias emerge under stress all contribute to an assessment of your overall cardiovascular fitness and risk.
Clinical Value
What the Test Can Reveal
Myocardial Ischaemia
ST-segment depression or elevation during exercise indicates reduced blood supply to the heart muscle. The more ST change and at the lower workload it appears, the more significant the underlying coronary disease. This typically warrants CT coronary angiography or invasive angiogram.
Exercise-Induced Arrhythmias
Some arrhythmias are triggered only by the catecholamine surge of exercise. Ventricular ectopics that increase with exercise, exercise-induced ventricular tachycardia, or atrial fibrillation provoked by exertion are clinically important findings that inform both diagnosis and management.
Functional Capacity (METs)
The maximum workload achieved is one of the most powerful predictors of long-term cardiovascular outcome. Achieving >10 METs is associated with an excellent prognosis even in the presence of coronary disease. Poor exercise tolerance (<5 METs) carries significant prognostic weight.
Blood Pressure Response
Blood pressure should rise with exercise. A fall in systolic pressure during increasing effort (exertional hypotension) is an important abnormal finding, suggesting severe multi-vessel or left main coronary disease and requiring urgent further assessment.
Heart Rate Recovery
The rate at which the heart rate falls in the first two minutes of recovery is a marker of vagal tone and autonomic function. Failure of heart rate to fall by ≥12 bpm in the first minute of recovery is an independent predictor of mortality.
Post-Treatment Assessment
The test is valuable for objectively assessing the benefit of coronary stenting or bypass surgery. Comparing pre- and post-procedure exercise capacity and ischaemic threshold confirms the effectiveness of revascularisation in concrete, measurable terms.
Standardised Methodology
The Bruce Protocol
Standard Exercise Protocol
Seven Progressive Stages
Each stage lasts 3 minutes. Speed and incline increase at every stage. The test is stopped at patient request, target heart rate achievement, or if a significant abnormality develops.
Target heart rate = 85% of age-predicted maximum (220 minus age). Most patients without significant coronary disease complete Stages 3–5. Modified Bruce Protocol (with gentler initial stages) is used for deconditioned patients or those with baseline limitations. METs = metabolic equivalents; 1 MET ≈ resting oxygen consumption.
Before Your Test
How to Prepare
Medications to Discuss
- Beta-blockers (bisoprolol, atenolol, carvedilol, metoprolol) should be withheld for 48 hours before the test — they prevent the heart rate from reaching target, making the test non-diagnostic. Discuss this with Dr Nijjer before stopping any medication.
- Rate-limiting calcium channel blockers (diltiazem, verapamil) may also need to be held — confirm with Dr Nijjer.
- All other medications should be taken as normal on the day of the test.
On the Day
- Wear comfortable clothing and supportive trainers suitable for running.
- Avoid eating a heavy meal for at least two hours beforehand.
- Avoid caffeine on the morning of the test.
- Bring a list of your current medications.
- An echocardiogram may be requested beforehand to confirm there is no resting structural abnormality that would affect interpretation.
Important: Tell Dr Nijjer if you have experienced chest pain, significant breathlessness at rest, or new symptoms since your last appointment. The test will be deferred if clinically appropriate. A doctor is present throughout the test and emergency resuscitation equipment is immediately available.
Understanding Your Findings
What the Results Mean
Negative result
No Evidence of Ischaemia
Achieving target heart rate without ST changes, symptoms, or blood pressure abnormalities is highly reassuring. A good exercise capacity (>10 METs) is associated with an excellent prognosis and rarely requires further ischaemia testing.
Equivocal result
Borderline Changes
Minor ST changes, failure to achieve target heart rate, or limiting symptoms without clear ECG abnormality may warrant further imaging. Stress echocardiography, stress perfusion cardiac MRI, or CT coronary angiography will provide definitive clarification.
Positive result
Significant Ischaemia Detected
Significant ST depression, exertional hypotension, early onset changes (Stage 1–2), or limiting symptoms strongly suggest obstructive coronary artery disease. Invasive coronary angiography — with possible angioplasty — is typically the next step.
Symptoms on Exertion?
We Can Investigate.
An exercise stress test is a straightforward, safe way to assess how your heart responds under demand. Dr Nijjer will interpret the results and advise on the appropriate next steps.