What is a stress test?
A stress test is a very commonly performed test to learn:
- How well your heart pumps blood.
- Whether your heart is receiving an adequate blood supply.
- How you perform on physical activity (riding a treadmill or stationary bike) compared with other people your age and sex.
- If your symptoms (chest discomfort, shortness of breath, feeling like your heart is racing or even dizziness) can be reproduced while performing physical activity.
This makes it easier to identify and evaluate certain heart issues, such as:
- Issues with your muscle or valves.
- Adequate blood supply to your heart muscle.
- Electric stability of your heart at rest and during exercise.
Cardiac stress tests help healthcare providers determine whether you need additional — often more invasive — testing to confirm a diagnosis or if treatment might lower your heart attack risk and make you feel better.
How does a stress test work?
A heart stress test starts by making your heart pump harder and faster. For many people, this includes walking on a treadmill or riding a stationary bicycle. That’s why the test is often called an exercise stress test.
Healthcare providers assess your response to the increased workload by measuring:
- Blood pressure.
- Heart rate.
- Oxygen levels.
- Electrical activity in your heart.
- How hard your heart is working compared with others your age and sex.
Why might I need a stress test?
You may need this test to detect heart problems like:
People with high-risk occupations (like pilots or professional athletes) may also need stress tests.
Who should have a cardiac stress test?
This test may be right for you if you have symptoms of heart disease, like:
- Angina, which is chest pain or discomfort due to poor blood flow to the heart.
- Arrhythmia, which is a rapid or irregular heartbeat.
- Shortness of breath (dyspnea).
- Feeling lightheaded or dizzy.
Stress tests are also for people with a heart disease diagnosis who:
- Would like to start exercising.
- Are undergoing treatment and healthcare providers need to determine how well it’s working.
- Face a higher risk of complications due to a personal or family history of heart disease.
- Have diabetes or other underlying conditions that increase your risk of heart disease.
- Require non-cardiac surgery and healthcare providers need to assess your risk of complications.
Providers may also do stress tests in people without known heart disease or symptoms to assess their risk for heart disease and heart attacks, especially if they have other risk factors like diabetes, high blood pressure, high cholesterol or a family history of premature heart disease.
What are the different types of stress tests?
There are many methods for assessing heart function while it’s hard at work. All cardiac stress tests involve checking your heart rate, blood pressure, oxygen levels and electrical activity. But there are some differences.
Stress test types include:
Exercise stress test
This is the most common and basic heart stress test. It involves walking on a treadmill or riding a stationary bicycle. A well-trained exercise physiologist usually tailors the speed and elevation of the treadmill to your ability to walk and your overall fitness.
If you can’t exercise, you receive medications that make your heart pump harder and faster or dilate the artery supplying blood to your heart (coronary arteries). An electrocardiogram (EKG) captures your heart’s electrical activity. Exercise stress tests check for signs of coronary artery disease.
Exercise stress echocardiogram
An exercise stress echocardiogram is similar to the basic stress test but provides more detail. Healthcare providers perform an echocardiogram (ultrasound of your heart) before and at peak exercise. This cardiac imaging test uses sound waves to evaluate blood flow through your heart as well as the pumping chambers of your heart (muscle) and valve functions.
You might need a stress echocardiogram if the results of your initial stress test are unclear. This study enables healthcare providers to observe blood flow through the heart’s chambers as well as the effects of exercise.
Nuclear stress test
This advanced heart stress test uses safe levels of a radioactive substance and a cardiac imaging scan to assess heart function. A healthcare provider takes pictures of your heart before (at rest) and after you exercise. A cardiologist compares the amount of blood flow to the muscle of your heart at rest and after stress. A decrease in blood flow signal usually indicates a blockage in one or multiple arteries in your heart.
Nuclear cardiac stress tests can:
- Determine the severity of blockage of coronary artery disease.
- Assess whether previous treatments, such as stents or bypass surgery are working as they should.
- Help you avoid more invasive heart tests, such as cardiac catheterization.
- Show whether your heart is healthy enough for non-cardiac surgery or exercise.
Cardiac rehabilitation stress test
If your healthcare provider recommends cardiac rehabilitation, the program may include stress testing. Rehabilitation is a medically supervised exercise program that helps people with heart disease become more physically active.
Cardiac rehabilitation stress testing includes:
- Entrance stress test: Helps the rehabilitation team develop an exercise program that’s appropriate for your capabilities.
- Exit stress test: Enables the team to measure your progress and create a long-term exercise program after you complete rehabilitation.
Who should not have an exercise stress test?
Cardiac stress testing isn’t for everyone. You might not need the test if you have:
- A coronary artery disease diagnosis, have undergone treatment and not had new symptoms for years and are doing well on medical therapy.
- No history of risk factors for coronary artery disease or coronary disease or symptoms.
- A low risk of heart disease, including people who do not smoke, are physically active and eat a heart-healthy diet.
The test is also not for people with heart conditions that make stress testing unsafe (contraindications). These include:
- Aortic dissection.
- Endocarditis, pericarditis or myocarditis (heart muscle inflammation).
- Recent heart attack.
- Severe aortic stenosis (aortic valve narrowing).
- Uncontrolled abnormal heart rhythm (arrhythmia).
- Ongoing chest pain.
Why is exercise stress test eligibility important?
Your healthcare provider may decide not to have you undergo stress tests or repeat “routine” stress tests to help you avoid unnecessary costs and treatments. An unindicated stress test may show results that prompt healthcare providers to recommend additional testing you don’t need. Some of these tests, including a coronary angiogram, carry a higher risk of complications than stress tests.
Cardiologists consider your overall health in determining whether a heart stress test is right for you. This determination includes your:
- Family history of heart disease.
- Health history.
- Level of physical activity.
- Risk factors like smoking, diabetes, high blood pressure and high cholesterol.
What’s important to know about exercise stress testing in women?
People designated female at birth (DFAB) tend to experience heart disease differently than designated male at birth (DMAB). This makes it challenging to detect early-stage heart disease. In general, healthcare providers tailor their stress testing and method of imaging during stress testing based on your sex and age to obtain optimal results and minimize radiation and unclear test results.
Is cardiac stress testing safe?
If there are no contraindications, exercise stress tests are safe. Very few people experience complications. Trained healthcare providers, typically an exercise physiologist and a cardiologist, are present during your test in the rare event that you have a complication. They assess your performance, data and symptoms throughout the tests and immediately provide emergency treatment if it’s needed. You also have the option of stopping the stress test at any time if you become anxious or uncomfortable.
A stress test shows how the heart works during physical activity. It also may be called a stress exercise test. Exercise makes the heart pump harder and faster. A stress test can show problems with blood flow within the heart.
A stress test usually involves walking on a treadmill or riding a stationary bike. A health care provider watches your heart rhythm, blood pressure and breathing during the test. People who can’t exercise may be given a medicine that creates the effects of exercise.
Your health care provider may recommend a stress test if you have symptoms of coronary artery disease or an irregular heart rhythm, called an arrhythmia.
A stress test can help:
- Guide treatment decisions.
- Show how well heart treatment is working.
- Show how serious a heart condition is.
Why it’s done
A health care provider may recommend a stress test to:
- Diagnose coronary artery disease. The coronary arteries are the major blood vessels that bring blood and oxygen to the heart. Coronary artery disease develops when these arteries get damaged or diseased. Cholesterol deposits in the heart arteries and inflammation usually cause coronary artery disease.
- Diagnose heart rhythm problems. A heart rhythm problem is called an arrhythmia. An arrhythmia can cause the heart to beat too fast or too slowly.
- Guide treatment of heart disorders. If you’ve already been diagnosed with a heart condition, an exercise stress test can help your provider know if your treatment is working. The test results also help your provider decide on the best treatment for you.
- Check the heart before surgery. A stress test can help show if surgery, such as a valve replacement or a heart transplant, might be a safe treatment.
If an exercise stress test doesn’t show the cause of symptoms, your provider may recommend a stress test with imaging. Such tests include a nuclear stress test or stress test with an echocardiogram.
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A stress test is generally safe. Complications are rare. Possible complications of an exercise stress test are:
- Low blood pressure. Blood pressure may drop during or right after exercise. The drop might cause dizziness or fainting. The problem will likely go away after the exercise stops.
- Irregular heart rhythms, called arrhythmias. Arrhythmias that occur during an exercise stress test usually go away soon after the exercise stops.
- Heart attack, also called myocardial infarction. Although very rare, it’s possible that an exercise stress test could cause a heart attack.
How you prepare
Your health care provider can tell you how to prepare for your stress test.
Food and medicine
You may be asked not to eat, drink or smoke for a time before a stress test. You may need to stay away from caffeine the day before and the day of the test.
Some medicines might have an effect on stress tests. Ask your health care provider if you can take your medicines before the test.
If you use an inhaler for asthma or other breathing problems, bring it to the test. Tell your health care providers that you use an inhaler.
Clothing and personal items
Wear or bring comfortable clothes and walking shoes.
What you can expect
Exercise stress test
Exercise stress test
In an exercise stress test, sensors taped to the chest record the heart’s rhythm. A health care provider checks the heartbeat while the person walks on a treadmill or pedals a stationary bike.
A stress test usually takes about an hour, including the prep time and the time it takes to do the actual test. The exercise part takes only around 15 minutes. It usually involves walking on a treadmill or pedaling a stationary bicycle. If you can’t exercise, you’ll receive medicine through an IV. The medicine creates the effect of exercise on the heart.
Before a stress test
Your health care provider usually asks questions about your medical history and how often and how hard you exercise. This helps the provider decide how much you can exercise during the test. Your provider usually listens to your heart and lungs to check for any issues that might affect your test results.
During a stress test
A health care provider puts sticky patches called electrodes on your chest and sometimes the arms and legs. Body hair may be shaved to help the patches stick. The patches record the heart’s rhythm. Wires connect the patches to a computer, which shows or prints the test results. This part of a test is called an electrocardiogram, commonly called an ECG.
A cuff on your arm checks your blood pressure during the test. You may be asked to breathe into a tube during the test to show how well you’re able to breathe during exercise.
Exercise may be on a treadmill or stationary bike. The pace is easy at first. As the test continues, the exercise gets harder. You can use the railing on the treadmill for balance. Don’t hang on tightly, as this may affect the results.
Exercise continues until your heart rate reaches a target level. You might need to stop sooner if you develop symptoms such as:
- Moderate to severe chest pain.
- Severe shortness of breath.
- Unusually high or low blood pressure.
- An irregular heart rhythm.
If you can’t exercise during the stress test, a health care provider gives you medicine by IV. The medicine increases blood flow to the heart. You might feel flushed or short of breath, just as you would if you were exercising. You might get a headache.
You can stop the test anytime you’re too uncomfortable. Your care provider might stop the test if there are concerns about the way your heart is acting during the test.
After a stress test
After exercising, you may be asked to stand still for several seconds and then lie down for a while. Your care provider watches for problems as your heart rate and breathing recover from the exercise.
When the test is done, you may return to your usual activities unless your provider tells you otherwise.
Stress test results helps your health care provider plan or change your treatment. If the test shows that your heart is working well, you may not need more tests.
If the test suggests you might have coronary artery disease, you may need a test called a coronary angiogram. This test helps health care providers see blockages in the heart arteries.
If the test results are OK but your symptoms get worse, your care provider might recommend more testing. Tests may include a nuclear stress test or a stress test that includes an echocardiogram. These tests give more details about how the heart works.
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