A stress test is one of the most useful tools doctors have for checking your heart health. It shows how your heart performs when it is working hard — not just at rest. If you have chest pain, shortness of breath, or a family history of heart disease, your family doctor may recommend this test. Understanding what it involves can help you feel more prepared and confident going into it.
What Is a Stress Test?
A stress test — also called an exercise stress test or cardiac stress test — measures how your heart responds to physical activity. Some heart problems only show up when your heart is beating fast and working harder than usual. That is why doctors use exercise to “stress” the heart on purpose, in a safe and controlled setting.
During the test, you will usually walk on a treadmill or pedal a stationary bike. The speed and intensity increase gradually over time. Your heart’s activity is monitored closely throughout the entire process.
However, not everyone can exercise safely during the test. If you have arthritis, a lung condition, or another health issue that limits physical activity, your doctor may give you a medication instead. This medication makes your heart work harder, similar to what exercise would do. This version is called a pharmacological stress test.
Why Do Doctors Order a Stress Test?
Doctors most often use a stress test to diagnose or assess coronary artery disease. This is a condition where a waxy substance called plaque builds up inside the coronary arteries — the blood vessels that supply oxygen-rich blood to your heart muscle.
Over time, plaque narrows these arteries and reduces blood flow to the heart. As a result, blood clots can form and may partially or fully block an artery. This can lead to angina (chest pain) or a heart attack.
The tricky part is that symptoms of coronary artery disease often do not appear when you are resting. They show up when your heart needs to pump more blood and oxygen — for example, during physical activity. A stress test can reveal these hidden problems by putting the heart under controlled strain.
What Problems Can a Stress Test Detect?
During a stress test, your care team watches for warning signs that not enough blood is reaching your heart. These warning signs include:
Abnormal changes in heart rate or blood pressure
Chest pain or shortness of breath, especially with mild effort
Irregular heart rhythms or unusual electrical activity in the heart
Inability to exercise for a normal length of time for your age
Keep in mind that other conditions — such as anemia, low physical fitness, or lung disease — can also affect how long you can exercise. Your doctor will consider all of these factors when reviewing your results.
In addition to coronary artery disease, doctors may also use a stress test to evaluate heart failure or problems with the heart valves. According to Mayo Clinic’s overview of stress testing, this test gives doctors valuable information that a resting exam simply cannot provide.
Types of Stress Tests
There are two main categories of stress tests: the standard exercise stress test and the imaging stress test. Your doctor will choose the right one based on your health history and what they are looking for.
Standard Exercise Stress Test
This is the most common type. It uses an electrocardiogram (ECG) to track and record your heart’s electrical activity throughout the test. An ECG shows how fast your heart is beating, whether the rhythm is regular, and how strong the electrical signals are.
During the test, your blood pressure will also be checked at regular intervals. In some cases, you may be asked to breathe through a special tube. This allows the care team to measure how well your lungs are working and how much air you are exhaling.
A standard stress test is helpful for spotting changes in the heart’s electrical activity during exercise. It can also show whether your heart is receiving enough blood while you are physically active.
Imaging Stress Test
An imaging stress test goes a step further. It captures pictures of your heart both during exercise and at rest. This gives your doctor a clearer view of how blood flows through the heart and how well the heart muscle is pumping.
One common type is the stress echocardiogram. It uses ultrasound waves to create moving images of your heart. Your doctor can see how well the heart’s chambers and valves are functioning under physical strain. This test can also reveal areas where blood flow is poor, or where heart muscle may have been damaged by a previous heart attack.
Furthermore, some imaging stress tests use a contrast substance (also called a tracer) that is injected into your bloodstream. This tracer travels to your heart and shows up on special scans, allowing doctors to see exactly how much blood is reaching different parts of the heart. Tests in this category include:
Nuclear stress test — uses a small amount of radioactive tracer (such as thallium or sestamibi) and a special camera to create images
Positron Emission Tomography (PET) stress test — uses a different type of tracer and provides very detailed images of blood flow
The amount of radiation involved in these tests is considered safe for most people. However, pregnant women should not have imaging stress tests that use a tracer, due to the potential risk to the baby.
Imaging stress tests are generally more accurate than standard stress tests. They are better at identifying coronary artery disease and can help predict the risk of a future heart attack. For more on cardiac imaging, visit Healthline’s guide to nuclear stress tests.
When Is an Imaging Stress Test Used Instead?
Your doctor may recommend an imaging stress test rather than a standard one in certain situations. These include:
You are unable to exercise long enough to adequately raise your heart rate
You have an abnormal heart rhythm that could affect the accuracy of a standard ECG reading
You have had previous heart surgery, such as a coronary bypass or angioplasty
Your doctor needs more detailed information than a standard test can provide
What to Expect During the Test
A cardiac stress test is typically performed at a hospital, cardiac care centre, or a specialist’s office. The test itself usually takes between 30 and 60 minutes, though preparation and recovery time may add to your visit.
Before the test, you will be asked not to eat, drink caffeine, or smoke for several hours. Wear comfortable walking shoes and loose-fitting clothing. Let your care team know about any medications you are taking, as some may need to be paused beforehand.
During the test, small sticky patches called electrodes are placed on your chest, arms, and legs. These connect to the ECG machine and monitor your heart continuously. You will start exercising at a slow pace, and the intensity will increase every few minutes.
The test will be stopped if you experience chest pain, extreme shortness of breath, dizziness, or if your heart shows any concerning changes. Your safety is the top priority throughout the entire process. After the test, you will rest while your heart rate and blood pressure return to normal.
Understanding Your Results
After your stress test, your doctor will review the results and discuss what they mean for your health. A normal result means your heart responded well to exercise and blood flow appeared adequate. An abnormal result may suggest that one or more coronary arteries are narrowed or blocked.
However, a stress test is not always definitive on its own. Your doctor may recommend further testing, such as a coronary angiogram or additional imaging, to get a clearer picture. Results are always interpreted alongside your symptoms, medical history, and other test findings.
According to Health Canada, heart disease remains one of the leading causes of death in Canada. Early detection through tests like this one plays a key role in managing and preventing serious cardiac events.
When to See a Doctor
You should speak with your family doctor if you notice chest discomfort, unexplained shortness of breath, heart palpitations, or unusual fatigue during everyday activities. These symptoms may warrant a stress test or other cardiac evaluation.
If you do not have a family doctor, a walk-in clinic can be a good first step. A walk-in doctor can review your symptoms and refer you for further testing if needed. Most provinces cover medically necessary cardiac testing under their provincial health plan — ask your provider about what is included in your coverage.
Do not wait for symptoms to become severe. Early evaluation can make a significant difference in treatment options and outcomes. As always, speak with a qualified healthcare provider before drawing any conclusions about your heart health based on symptoms alone.
Frequently Asked Questions
What does a stress test show?
A stress test shows how your heart responds when it is working hard during physical activity. It can reveal blocked or narrowed arteries, irregular heart rhythms, and areas of the heart that are not receiving enough blood. Doctors use it to diagnose conditions like coronary artery disease and to assess the risk of a future heart attack.
Is a stress test painful or dangerous?
A stress test is generally safe and not painful, though you will feel your heart rate rise and your breathing quicken as the exercise intensifies. The test is performed under close medical supervision, and it will be stopped immediately if any concerning symptoms appear. Serious complications are very rare.
How long does a stress test take?
The active exercise portion of a stress test usually lasts between 8 and 12 minutes, but the full appointment — including preparation, monitoring, and recovery — typically takes 30 to 60 minutes. An imaging stress test may take longer due to the scanning involved.
Do I need a referral to get a stress test in Canada?
In most Canadian provinces, you will need a referral from a family doctor or walk-in clinic physician to have a stress test covered under your provincial health plan. Your doctor will assess your symptoms and decide whether the test is medically necessary. In some cases, a cardiologist referral may also be required.
What is the difference between a standard and an imaging stress test?
A standard stress test uses an ECG to monitor the heart’s electrical activity during exercise, while an imaging stress test also captures detailed pictures of the heart using ultrasound or a radioactive tracer. Imaging stress tests provide more information and are better at detecting certain heart conditions, particularly in people with complex medical histories.
Can I have a stress test if I cannot exercise?
Yes. If you are unable to exercise due to arthritis, a lung condition, or another health issue, your doctor can administer a medication that mimics the effect of exercise on the heart. This is called a pharmacological stress test and is a safe alternative for people who cannot complete the physical portion of the standard test.
Key Takeaways
A stress test checks how your heart functions during physical activity, revealing problems that may not appear at rest.
It is most commonly used to diagnose coronary artery disease and assess the risk of a heart attack.
There are two main types: the standard exercise stress test (using an ECG) and the imaging stress test (using ultrasound or a radioactive tracer).
If you cannot exercise, a pharmacological stress test uses medication to safely stress the heart instead.
Imaging stress tests are more detailed and better at detecting complex heart conditions than standard tests.
In Canada, most stress tests are covered under provincial health plans when medically necessary — talk to your family doctor or visit a walk-in clinic to get started.
Always consult a qualified healthcare provider if you experience chest pain, shortness of breath, or other concerning cardiac symptoms.
