An exercise stress test is used to determine how well your heart responds during times when it’s working its hardest. During the test, you’ll be asked to exercise — typically on a treadmill — while you’re hooked up to an electrocardiogram (EKG) machine. This allows your doctor to monitor your heart rate.

Stress tests are generally considered safe, especially since they’re done in a controlled environment under the supervision of a trained medical professional.

However, there are some rare risks, such as:

• chest pain
• collapsing
• fainting
• heart attack
• irregular heartbeat

However, your risk of experiencing these reactions during the test is low, since your doctor will screen you for problems beforehand. People who run the risk of these complications — such as those with advanced coronary heart disease — are rarely asked to do the test.