What Is a stress test?
Doctors use a stress test, also known as an exercise test or a treadmill test, to see how well a patient’s heart works during physical activity.
A stress test can also help a doctor advise patients on the best type of physical activity for them. A stress test usually involves walking on a treadmill or riding a stationary bike while monitoring the patient’s breathing, blood pressure, and heartbeat.
Some patients, such as those with arthritis, will not be able to do the activities involved in a stress test during exercise. Instead of exercising, the patient can take medication to make the heart work harder, as might happen during exercise.
Types of stress tests
We recommend different types of stress tests based on your general health and symptoms. Our doctors and imaging specialists are experienced in performing stress tests and interpreting the results.
1. Cardiopulmonary exercise test (CPET):
This comprehensive test assesses how well your heart and lungs are working together to deliver oxygen-rich blood to your body. It also shows how well your muscles are using oxygen while you exercise at increased levels. CPET can evaluate:
- Reasons for shortness of breath
- Fitness level and ability to exercise, especially after a heart attack or heart surgery
- Lung function
The CPET test is similar to the exercise stress test but it also measures lung function, including:
- The amount of oxygen your body uses during exercise
- Your breathing pattern
- The amount of carbon dioxide you produce
We use this test not only to identify many types of heart and lung disease but also to:
- Monitor people who already have these conditions and check for disease progression
- Measure how well treatments are working
- Determine if the exercise restrictions are due to a heart or lung problem
2. Exercise stress test
This test uses an EKG during exercise to assess blood flow to your heart. We do a stress test while exercising on the treadmill or stationary bike at a gradually increasing rate. We use this test to raise your heart rate so we can detect heart problems affecting blood flow.
The exercise stress test only measures the electrical activity of your heart, not the lung function like CPET. We use this test to:
- Determining safe levels of exercise after a heart attack or heart surgery
- Diagnosing and determining the severity of coronary heart disease and other types of heart disease
- Diagnose an arrhythmia
- Find out what causes symptoms that only appear during exercises, such as shortness of breath, fainting or an irregular heartbeat
- Treatment planning guidance, such as medications, cardiac catheterization (minimally invasive heart procedures), surgery or implantation
3. Pharmacologic stress test
This stress test assesses the blood flow to your heart using an EKG but does not involve any physical activity. We recommend a drug stress test for people who are unable to exercise due to physical limitations such as arthritis, joint or back conditions, injury or disability. For this test, you receive medication to stimulate your heart and make it beat harder and faster as if you were exercising.
Use the drug stress test to:
- Determine safe levels of physical activity if you have a heart attack or heart surgery
- Diagnosing many types of heart disease and determining their severity
- Guiding decisions about treatment options, such as medication, cardiac catheterization (minimally invasive heart procedures), surgery or implantation
- Evaluate how well your treatment increases blood flow to the heart
4. Nuclear stress test
This type of stress test includes a radioactive dye and imaging studies to show blood flow to the heart, both at rest and when the heart rate is elevated. As with other types of stress tests, we record the electrical activity of your heart with an EKG.
During a nuclear stress test, you receive an injection of a radioactive dye through an intravenous (IV) line. The dye travels through the bloodstream and your heart. While you’re still at rest, we scan your heart with a special camera that captures the radioactive dye to show blood flowing into and through your heart.
In the second part of the test, you start exercising on a treadmill or stationary bike. If you are unable to exercise, we can give you medicine to increase your heart rate. Then we check more images of your heart to capture blood flow to the heart during increased activity.
Nuclear stress tests show which parts of the heart are receiving enough blood and which ones are not. The tests provide details that can indicate heart disease and severity and show tissue damage from a previous heart attack.
Why stress test is done?
Your doctor may recommend a stress test to:
- Diagnose coronary artery disease: Coronary arteries are the main blood vessels that supply your heart with blood, oxygen, and nutrients. Coronary artery disease develops when these arteries are damaged or sick – usually due to a buildup of plaques containing cholesterol and other substances (plaques).
- Diagnose heart rhythm problems (arrhythmias): Arrhythmias occur when the electrical impulses that coordinate your heart’s rhythm do not work properly, causing your heart to beat too fast, too slowly or irregularly.
- Guide treatment of heart disorders: If you’ve already been diagnosed with heart disease, an exercise stress test can help your doctor know how well treatment is working. It can also be used to help create a treatment plan for you by showing how much exercise your heart can handle.
- Your doctor may use a stress test to help determine the timing of heart surgery, such as valve replacement. In some people with heart failure, results of a stress test may help a doctor determine whether you need a heart transplant or other advanced treatments.
Your doctor may recommend an imaging test, such as a nuclear stress test or an echocardiogram stress test if an exercise stress test doesn’t determine the cause of your symptoms.
By what means should I prepare for the exercise stress test?
- Do not eat or drink anything except water for the 4 hours before the test.
- Do not drink or eat anything containing caffeine for the 12 hours before the test.
- Do not take the following heart medications on the day of the test, unless your doctor tells you otherwise or if medication is needed to treat chest discomfort on the day of the test:
- Isosorbide dinitrate(for example, Isordil, Dilatrate SR)
- Isosorbide mononitrate(for example, ISMO, Imdur, Monoket)
- Nitroglycerin(for example, Deponit, Nitrostat, Nitro-Bid)
- If you are using a breathing inhaler, bring it to the test.
You may also be asked to stop taking other heart medications on the day of the test. If you have questions about your medications, ask your doctor. Do not stop taking any medication without first consulting with it.
During the stress test
You will slowly start exercising on a treadmill or stationary bike, then gradually increase the speed of the treadmill or resistance bike until your heart works at the target heart rate for your age. Most often, the stress test includes an electrocardiogram to measure the electrical activity of your heart while you exercise on a treadmill or on a stationary bike. Your doctor may also measure the blood oxygen level, blood pressure, heart rate.
During the test, you’ll exercise for 10 to 15 minutes. And we have better stress test equipment. Your primary care physician will stop the test on the off chance that you give any indication of a heart issue, in the event that you are too worn out to even consider continuing the test.
If you are not able to exercise, your doctor will give you the medication for over 10 to 20 minutes through an intravenous (IV) line into a blood vessel.
Your doctor may also take pictures of your heart during or immediately after a stress test to see how well blood flows through your heart and how well your heart pumps blood when it beats. These images can be taken by echocardiogram or by injecting a radioactive dye into a vein, which is called a nuclear heart scan. The amount of radiation in the dye is safe for you and those around you. However, if you are pregnant, this test should not be performed due to the risks it may pose to your unborn baby.
If your doctor also wants to know how well your lungs are working, you may be asked to wear a mask or mouthpiece to measure the gases you breathe in during the stress test.
Following up after an exercise stress test
After the test, you will be given water and asked to rest. If your blood pressure rises during the test, the nurse may continue to monitor your blood pressure.
A couple of days after the test, your primary care physician will survey the outcomes with you. The test can reveal an irregular heartbeat or other symptoms that indicate coronary artery disease, such as blocked arteries.
If your doctor determines that you may have coronary artery disease or other heart problems, he may begin treatment or order further tests, such as a nuclear stress test.
These tests are usually safe. Sometimes, exercise or medication that increases the heart rate can cause symptoms such as chest pain, dizziness, or nausea. You will be monitored closely throughout the test to reduce the risk of complications or to treat any health problems quickly.
The radioactive dye used for a nuclear stress test is safe for most people. In rare cases, it may cause an allergic reaction. Also, a nuclear stress test is not recommended for pregnant women, as the dye may be harmful to a fetus.
If the information gathered during the exercise stress test shows that your heart function is normal, you may not need any other tests. However, if the results are normal and symptoms continue to worsen, your doctor may recommend nuclear or other stress tests that include an echocardiogram before and after exercise or taking medications to increase blood flow to your heart. These tests are more exact and give more data about your heart work, yet they are likewise more costly.
If the stress test results indicate the possibility of coronary artery disease or an irregular heartbeat, your doctor will use the information to create a treatment plan. You may require extra tests, for example, a coronary angiogram. If you have a stress test to help determine a treatment for heart disease, your doctor will use the results to plan or change your treatment.