A stress test, better known as exercise stress test, is performed by a doctor or a trained technician to reveal the amount of stress that the heart can manage before showing symptoms of an abnormal rhythm or signs of ischemia (compromised blood flow to heart). During this test, you will have to walk on a treadmill or pedal a stationary bike, and gradually increase the difficulty, while your blood pressure, heart rate and electrocardiogram are monitored. But what does a stress test show? Let's get close and find out.

Why Do I Need A Stress Test?

Stress test or exercise stress test aims at gathering and providing information on how well the heart responds to stress physiologically by assessing heart rate and blood pressure changes under stress. But, the burning question here is why do I need a stress test? Well, stress test can be used to:

• Determine if there is adequate blood flow to heart muscles during activities;
• Determine your chances of suffering from coronary heart disease and if you require further evaluation;
• Assess the effectiveness of the drugs you've been taking to keep control over angina and ischemia;
• Assess the effectiveness of procedures done in coronary disease patients to improve blood flow;
• Look for abnormal heart rhythms;
• Assist you in devising a safe exercise plan;
• Check for improperly functioning valves.

What Does A Stress Test Show?

During a stress test, a doctor will gently clean 10 small areas on your chest and then place small, sticky and flat patches, called electrodes on the said places. The 10 patches are linked to an EKG or electrocardiograph monitor to record the electrical activity of your heart during the test.

Stress test is used to show the function of your heart during exercises and how healthy it is by monitoring heart's electrical activity, blood pressure and other numbers on the EKG.

• In case of normal standard test results, further evaluation is not needed. However, despite a normal standard test result, you’re still advised to go for further evaluation due to symptoms like chest pain and shortness of breath.
• An abnormal test means improper heart blood supply, which may indicate an underlying coronary heart disease (CHD) and at times is a sign of poor health and physical fitness. If you have an abnormal result, or are unable to exercise, an imaging stress test is the next step. Although imaging stress tests are expensive, they can accurately locate the parts of heart that are not contracting strongly, are not getting enough blood, or are dead.

What Are The Types of Stress Tests?

Now that you know the answers to "What does a stress test show?" and why you need it, let's briefly discuss the different types of stress tests that can be performed:

• Treadmill stress test: if you have a normal ECG and can walk, then you're fit for this test. You’re being monitored while walking on the treadmill. Pain or a change in ECG can indicate a compromised blood flow to heart.
• Dobutamine or Adenosine stress test is an option if you're unable to exercise. This involves administration of a drug which elicits a response in heart similar to that in exercise. This way the doctor can see your heart's performance under stress without having you exercise.
• Stress echocardiogram stands out by revealing lack of blood flow, which other heart tests fail to show. An echo is basically a graphical presentation of the heart's movement. It visualizes the heart activity (pumping action) under stress.
• Nuclear stress test involves administration of a radioactive substance into heart, which emits rays and can be identified by a special camera. It gives clear pictures of heart tissues (at rest and during exercise) that can be seen on a monitor. This test exactly locates the functioning and non-functioning parts of heart along with the areas where blood supply is reduced.

Are There Any Risks?

Since you have known "What does a stress test show?" you should also be informed of the risks of this test. Stress test is a relatively safe test and complications are rare; however, risks and complications are part and parcel of medical procedures. And potential risks of this test are:

• Low blood pressure: Blood pressure may drop during the test and you may feel dizzy and even faint. This however resolves as soon as you stop exercising.
• Arrhythmia, or abnormal heart rhythm in simple words, also gets back to normal on stopping the exercise.
• Heart attack or a myocardial infarction is an extremely rare occurrence but could be stimulated by the test.

Know the purpose and methods of performing a stress test from the following video: