How Do I Prepare for a Stress Test?
It's important to follow your doctor's instructions closely prior to a stress test. Depending upon whether you have an exercise stress test or a pharmacologic one you may be instructed to not eat, abstain from food and drinks with caffeine, and stop certain medications.
Exercise Stress Test
- Discuss with your doctor the reasons for the test as well as the risks and alternatives. If your risks are too high the test may be postponed or canceled. Additionally, your doctor needs to be aware of your medical history, ability and desire to walk on a treadmill. Review the article on “Reasons Not to Have the Test” for more information.
- Do not eat or drink anything for at least 4 hours prior to the test.
- Your doctor may ask you to not eat or drink anything with caffeine (soda, coffee –- both regular and decaf, tea, or chocolate) for 12 hours prior to the test (see below for reason).
- Wear comfortable clothing and appropriate footwear such as gym shoes.
- Discuss with your doctor whether you should stop some of your medications in preparation for the test. It is common to stop certain blood pressure medications for 24 to 48 hours prior to the test.
Pharmacologic Stress Test: Adenosine/Dipyridamole/Dobutamine
The protocol for a treadmill stress test described above applies to pharmacologic stress tests as well.
If you are unable to walk on the treadmill for long enough to achieve 85% of your age-predicted maximum heart rate (see below), the test may be changed to an adenosine/dipyridamole stress test.
Age-predicted maximum heart rate = 220-Age
The reason to abstain from caffeinated food and drinks for 12 hours prior to an exercise stress test is because of the possibility of changing (converting) to an adenosine or dipyridamole stress test. The caffeine interferes with the pharmacologic agent and makes the test less useful.
Sources:
ACC/AHA/ASNC 2003 Guidelines for the Clinical Use of Cardiac Radionuclide Imaging
American College of Cardiology Appropriateness Criteria for a Nuclear Stress test.
ACC/AHA 2002 Guideline Update for Stress Testing.