A stress test shows how your heart works when it has to work harder. Some heart problems only show up with effort, so a resting EKG can look normal even when something is wrong. Here's what happens and how to get ready.
Why it's ordered
Common reasons include:
- Chest pain, pressure or shortness of breath with activity
- Checking for blocked heart arteries (coronary artery disease)
- Seeing how well a treatment is working
- Deciding whether it's safe to start an exercise program
- Checking an irregular heartbeat that comes on with exercise
The kinds of stress test
Exercise stress test. You walk on a treadmill while we watch your EKG, heart rate and blood pressure. The speed and incline go up every few minutes.
Stress echocardiogram. An ultrasound of your heart is taken at rest and again right after exercise, so we can see how the heart muscle moves under strain.
Nuclear stress test. A small amount of a tracer is injected, and a camera takes pictures of blood flow to the heart at rest and after stress. This one takes longer, often a few hours with waiting time between pictures.
Medication stress test. If you can't walk on a treadmill, a medicine is used to make your heart work as if you were exercising.
Your cardiologist will tell you which one you're having.
How to prepare
Follow the instructions you're given for your test. In general:
- Food. Don't eat for a few hours before the test. Water is usually fine.
- Caffeine. Avoid coffee, tea, soda, chocolate and decaf for 24 hours before a nuclear or medication stress test. Caffeine can block the medicine used in the test.
- Your medicines. Ask whether to take your usual medicines that morning. Some heart medicines, like beta blockers, are sometimes held. Don't stop anything on your own.
- Diabetes. Ask how to adjust insulin or diabetes pills if you're fasting.
- Clothes. Wear comfortable clothes and walking shoes. Skip lotion on your chest so the EKG stickers stay on.
- Inhaler. If you use one, bring it.
During the test
A technician places stickers on your chest for the EKG and a cuff on your arm. You start slowly, and the test gets harder in stages. Tell us right away if you feel chest pain, dizziness or unusual shortness of breath. We'll stop when you reach your target heart rate, when you're too tired to go on, or if the monitors show a reason to stop.
Afterward you rest while your heart rate and blood pressure come back down.
After the test
Most people go back to normal activity the same day. Your cardiologist will review the results and go over them with you, including whether you need more testing or a change in treatment.
