Nuclear Stress Testing: What It Is and What to Expect
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor provides Nuclear Stress Testing?
A cardiologist, a heart doctor, usually provides and reads a nuclear stress test. The test is done at a medical center or health care provider's office. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What it is
A nuclear stress test is an imaging method that uses radioactive material to show how well blood flows into the heart muscle, both at rest and during activity. The pictures are taken before and after your heart has worked its hardest.
Why a doctor might recommend it
The test is done to see if your heart muscle is getting enough blood flow and oxygen when it is working hard.
Your provider may order this test for reasons such as these.
- To find out how well a treatment, such as medicines or heart surgery, is working.
- To check your heart before you start an exercise program or have surgery.
- To find the cause of new chest pain.
The results can help diagnose coronary artery disease.
How to prepare
Common preparation steps include the following.
- Wear comfortable clothes and shoes with non-skid soles.
- Follow your provider's instructions about what to do before the test.
- You may be asked not to eat or drink after midnight, but you can have a few sips of water to take medicines.
- Avoid caffeine for 24 hours before the test.
- If you are or could become pregnant, or are breastfeeding, talk with your provider before the test.
What happens during it
A radioactive substance is injected into a vein. You lie down and wait for 15 to 45 minutes. Then a special camera scans your heart and creates pictures.
Most people then walk on a treadmill or pedal an exercise machine. If you cannot exercise, you may be given a medicine instead. Your blood pressure and heart rhythm are monitored throughout the test.
When your heart is working as hard as it can, a radioactive substance is injected again. You wait for 15 to 45 minutes. The camera then scans your heart a second time.
If any symptoms occur during your test, tell the person performing the test right away.
Recovery
Your provider compares the first and second sets of pictures using a computer. A normal result means blood flow through the coronary arteries is probably normal. What your results mean depends on the reason for the test, your age, and your history of heart and other medical problems.
An abnormal result may be due to reduced blood flow to a part of the heart. The most likely cause is a narrowing or blockage of one or more of the arteries that supply your heart muscle. After an abnormal result, you may need a change in your heart medicines, or a procedure such as heart bypass surgery.
Risks and side effects
Stress tests are usually safe, and you are closely watched during the test. Complications are rare, but they may include problems with heart rhythm, extreme swings in blood pressure, and skin rashes. Your provider will explain the risks before the test.
Call 911 or go to the emergency room if you have chest pain or discomfort lasting two minutes or more, trouble breathing, or fainting.
Who performs it
A health care provider injects the radioactive substance. A provider also takes the pictures of your heart.
Common questions
Do I need to avoid caffeine before a nuclear stress test?
Yes, you will need to avoid caffeine for 24 hours before the test. This includes tea and coffee, all sodas, even ones labeled caffeine-free, chocolates, and certain pain relievers that contain caffeine.
What if I cannot exercise for a nuclear stress test?
If you cannot exercise, you may be given a medicine instead. One kind of medicine widens your heart arteries. Another kind makes your heart beat faster and harder, similar to when you exercise.
Can I take my regular medicines on the day of the test?
It depends, so ask your provider whether to take your medicines as usual. Do not stop or change your medicines without talking to your provider first.
How does a direct primary care or concierge doctor fit in?
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
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Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
