Before a stress test, you’ll need to avoid food, drink, tobacco, and caffeine for a time. You may also have to stop taking some medications. Your doctor will provide information specific to you, but there are some general guidelines.

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A clinician may ask you to take a stress test to determine if you have cardiac disease and assess your heart attack risk. They may either recommend a treadmill (exercise) stress test or a pharmacologic (chemical) stress test, when they give you medications to increase your heart rate.

A healthcare professional typically gives you instructions specific to you based on the medications you take and your overall health. The following guidelines may help you understand what to expect if you are about to take a stress test.

A healthcare professional usually recommends not eating or drinking at least 3 hours before your test, but it could be longer. Avoiding eating solid foods can help make sure you do not feel sick during the test. It also helps you exercise to your best capacity.

If you have diabetes, talk with a doctor about a plan to ensure your blood sugar remains stable. You may need to adjust your insulin the day of your test.

You may wish to bring a light snack with you so you can eat something after you complete your stress test.

Can I drink water before a stress test?

You can usually drink water and other clear liquids before your stress test. Examples of clear liquids include apple or cranberry juice.

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It’s important to avoid caffeine before a stress test. If taking a chemical stress test, avoid caffeine for at least 12 to, ideally, 24 hours before your test. Caffeine blocks the effectiveness of adenosine, a medication that doctors commonly give during a chemical stress test.

Avoid caffeinated drinks to help ensure your stress test is as accurate as possible. Also, be aware of foods that may contain caffeine, such as:

  • chocolate
  • cereals
  • energy bars

Some headache medications may also contain caffeine.

Avoid smoking or using any tobacco products before a stress test.

You should also refrain from using products that contain nicotine, such as:

  • electronic cigarettes
  • vapes
  • patches

Also avoid the use of any recreational drugs, including cannabis.

If you take beta-blockers or calcium channel blockers (CCBs) to manage your heart rate or blood pressure, a healthcare professional will likely recommend that you stop taking them 24 to 36 hours before your test.

Beta-blockers commonly end in “-ol,” such as:

  • metoprolol
  • carvedilol
  • propranolol

CCBs commonly end in “-pine,” such as:

  • amlodipine
  • felodipine
  • nifedipine

Other CCBs include diltiazem and verapamil.

Additional medications a healthcare professional may suggest discontinuing before the test include:

Tell your doctor about all the medications you take, including any over-the-counter ones.

For treadmill testing, wear comfortable clothing to ensure you can participate fully. Wear running or walking shoes and clothing suitable for exercising.

Wearing a button-down shirt can help your monitoring technician place electrodes on your chest easily.

The following are some frequently asked questions about cardiac stress testing. But always ask your healthcare team, as they may have information specific to you.

Can I shower before a stress test?

Unless otherwise directed, you can take a shower before your stress test. But avoid applying lotions, powders, or perfumes to the chest area before your test. This can keep the electrode pads from sticking well to your chest.

Can I drive myself to and from a stress test?

The answer to this may depend upon your healthcare professional and overall health. While some healthcare professionals may allow you to drive yourself to and from a stress test, others may ask that you have someone to drive you home after.

Because you receive medications or perform exercise in a way that stresses your heart, it’s hard to predict how you will feel after the test. To travel most safely, have someone drive you home.

What can cause you to fail a stress test?

A stress test aims to raise your heart rate to an expected value for your age. If you can do this without chest pain, you are at a lower risk of death from a cardiac event. You are at increased risk if it’s difficult to raise your target heart rate or if you have chest pain before raising your target heart rate.

A healthcare professional typically reviews your test results with you after your test.

Stress test preparation tips

Here’s a review of some tips to help you prepare for your stress test:

  • Know what medications to take and stop taking, including over-the-counter medications like vitamins.
  • Refrain from eating at least 3 hours before your stress test.
  • Avoid eating or drinking caffeine-containing products anywhere from 12 to 24 hours before a stress test.
  • Wear loose, comfortable clothing.
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Cardiac stress testing is a noninvasive way to help your clinician assess your cardiovascular health and risk of death from a heart attack. You’ll usually receive preparation instructions that include considerations for the medications you take. The instructions also typically tell you what and when you can eat and drink before your test.

If you need clarification about any of the instructions, ask your clinician, as they want you to have the most reliable test.