What happens during an exercise stress test?


You’ve been experiencing chest discomfort during your evening walk or when climbing stairs. It disappears once you stop moving but it troubles you nonetheless. Discussing these symptoms with your doctor is strongly advised whenever you have unusual or out-of-the-ordinary aches and pains. When you do, one of the most common tests checking for a heart condition is the exercise stress test. 

Exercise stress tests, treadmill tests, or an exercise electrocardiogram (ECG) are vital tools utilized for many years. As recently as a decade ago, exercise stress tests were often ordered as part of a routine check-up in middle-aged adults, regardless of symptoms. However, today they are mainly done in people with symptoms that suggest heart disease. Usually, when someone has predictable chest pain patterns during exercise or over exertion, it is often diagnosed as angina.  Angina happens when the heart muscle isn’t receiving enough blood, usually during physical activity.

What does an exercise stress test measure?

The purpose of an exercise stress test is to use an electrocardiogram to record the heart’s electrical activity. The ECG reading can discover changes that can point to abnormalities in blood flow caused by blockages within arteries or other heart-related problems. Exercise stress tests can also evaluate a person’s readiness before a cardiac rehabilitation program or exercise regimen begins.  

I haven’t exercised for a while.  Should I get a stress test before starting working out?

It depends. Everyone is different depending on their baseline risk for heart disease.  Is there a strong family history of heart disease?  How long have you been inactive?  What type of physical activity are you planning on taking up? 

For example, let’s say you’re a person over 60 with a family history of heart disease wanting to become more physically active by taking a daily walk with your dog.  You probably don’t need a stress test.  But, if you sign up for a 5K or longer marathon and you’ve been a couch potato for years, you should consult your doctor about getting an exercise stress test before starting training.

What happens during an exercise stress test?

Exercise stress tests are usually conducted by an exercise physiologist and supervised by a physician. The exercise physiologist will review your medical history, asking questions about your family health history and what heart-related symptoms you are having. They will also inquire about joint problems with your knees, hips, or ankles.  

Some exercise stress tests will use a treadmill but some may use an exercise bike. In addition, anyone unable to use their legs can use an arm-powered exercise machine. 

The person administering the stress test will place small, sticky adhesive pads on your chest and abdomen. Men may need to shave some chest hair for the pads to stick.  Women can wear a sports bra with the chest pads placed just above and below the breasts. Each pad is attached to a plastic-coated wire that feeds into the ECG system.  A cuff on your arms periodically measures your blood pressure.

Before beginning the test, a baseline reading will be taken while you’re at rest.  Then you will begin walking on a treadmill at a slow pace (under 2 mph).  As you walk on the treadmill, the clinician monitors your heart’s electrical activity, heart rate, and blood pressure. The speed and steepness of the treadmill will be increased every few minutes, making you work harder. The goal is to exercise until you are too tired or out of breath.  Some people may experience leg or chest pain causing them to stop. If the clinician discovers worrisome ECG or blood pressure changes, they will stop the test. 

Interpreting the results

The findings will either indicate everything is normal, abnormal or unclear. For example, no exercise stress test is 100% accurate and about 10% to 15% of people with normal results may have significant coronary heart disease. However, the opposite is true as up to 15% of people with an abnormal reading do not have heart disease. 

If the results come back abnormal, this will warrant additional tests.  An exercise ECG test that likely indicates further testing includes:

  • ECG changes signaling the heart isn’t getting enough blood, likely because of artery narrowing or blockages.
  • If the heart is not beating as fast as it should with strenuous exercise or it is taking too long to slow down after exercise, you may have an electrical problem or another heart abnormality.
  • If your systolic blood pressure (the top number) does not rise by at least 10 to 20 mm Hg or begins falling during exercise, you have heart muscle or valve abnormalities.
  • If unusual heart rhythms are found, it may suggest coronary artery disease, cardiomyopathy, or an inherited heart problem. 

Takeaway message

Exercise stress tests are meant to be an interpretive tool for diagnosing coronary artery disease (CAD) or other heart issues. However no interpretive tool is 100% perfect or accurate. If your results come back positive for possible CAD, it simply means further testing will likely be advised. And even if your stress test is negative for heart disease, heart attacks can happen with small blockages that can break off and form clots.  Unfortunately, these smaller blockages often have few if any symptoms until a heart attack occur. But, knowing your family medical history, especially family heart disease history, can help determine if you need additional testing. 

Bottom line, your doctor will be your best guide and source of information on interpreting your exercise stress test results and advising you on what steps to take. 


Dr. David Samadi is the Director of Men’s Health and Urologic Oncology at St. Francis Hospital in Long Island. He’s a renowned and highly successful board certified Urologic Oncologist Expert and Robotic Surgeon in New York City, regarded as one of the leading prostate surgeons in the U.S., with a vast expertise in prostate cancer treatment and Robotic-Assisted Laparoscopic Prostatectomy.  Dr. Samadi is a medical contributor to NewsMax TV and is also the author of The Ultimate MANual, Dr. Samadi’s Guide to Men’s Health and Wellness, available online both on Amazon and Barnes & Noble. Visit Dr. Samadi’s websites at robotic oncology and prostate cancer 911. 

What happens during an exercise stress test?
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Dr. David B. Samadi