Stress tests measure the amount of stress your heart can manage before it beats in an irregular rhythm or affects your blood flow. The exercise stress test is the one doctors use most often, including for people who have diabetes.

Also called an exercise electrocardiogram, treadmill test, graded exercise test, or stress ECG, an exercise stress test can tell your doctor how well your heart handles physical activity. You typically walk on a treadmill or pedal a stationary bike while your doctor watches your heart rate and blood pressure.

Your doctor uses this test to:

See if your heart gets enough blood when you’re physically active
See how likely you are to have coronary heart disease
Check for abnormal heart rhythms
Find out how well your heart medications are working or see if any procedures you’ve had done have improved the blood flow in your heart vessels
Help figure out a safe exercise program for you

How Should I Prepare for the Exercise Stress Test?
Your doctor will give you specific instructions on what to do before your stress test. If you have diabetes, ask them if you should take your medication before the test.

If you take insulin to control your blood sugar, ask your doctor how much medication you should take the day of the test and if you should eat a light meal.
If you take pills to control your blood sugar, you may be told to wait and take your medication after the test.
If you have a glucose monitor, bring it with you to check your blood sugar levels before and after your exercise stress test. If you think your blood sugar is low, tell the lab technician right away.

Don’t drink or eat foods with caffeine for 24 hours before the test. Caffeine can affect the results of your test.
You may be told not to take certain heart or blood pressure medications the morning of the test that could affect your results. If you have any questions about your medications, ask your doctor. Don’t stop taking any medication without talking with your doctor first.
If you use an inhaler for your breathing, you may need to bring it with you.
On the day of the test, wear soft-soled shoes that are good for walking and comfortable clothes. Don’t bring any valuables.