Most people become exhausted while working out and playing sports. Some people, however, experience syncope from exercising. Syncope is the medical term for when someone passes out. Other people can become so exhausted and fatigued that they feel as if they could pass out even though they don't, which is called near syncope. 

If you or your child passes out or almost passes out during exercise or while playing sports, you will need what is called stress testing. A stress test will help your cardiologist see what your heart does while you're exercising. Here are a few heart conditions that may cause syncope or near syncope, what a stress test involves, and how to prepare for one. 

What Heart Problems Cause Syncope?

Passing out when exercising can be caused by a heart condition, including the following structural heart conditions, which are life-threatening:

  • anomalous coronary artery
  • arrhythmogenic right ventricular dysplasia
  • hypertrophic cardiomyopathy
  • myocarditis
  • noncompaction cardiomyopathy
  • Brugada syndrome
  • long QT syndrome

What Is a Stress Test?

A stress test is sometimes called an exercise test. It's done to see how your heart reacts when you exercise. It is done with an electrocardiogram and a treadmill. The electrocardiogram machine is connected to you via specifically placed electrodes on your chest. This machine will measure how hard your heart works. You will also have a blood pressure cuff placed on your arm to continually measure your blood pressure. 

How Is the Test Done?

First, you will be asked to walk on the treadmill. A doctor will monitor the electrocardiogram and your blood pressure while you walk. You will be asked to pick up the pace of your walking until you're jogging and several more times until you're running. If you feel dizzy or feel as if you could faint at any time during the stress test, tell the doctor or other medical professional who is conducting the test.

How Do You Prepare for the Test? 

It's important to follow all instructions from your doctor before and during the stress testing, particularly when it comes to caffeine intake and the medication you are taking. Caffeine and some prescription medications can interfere with the test and make it more difficult for your doctor to complete their evaluation of your heart and find the cause of your syncope or near syncope. Also, you should eat a light breakfast the morning of the test and wear comfortable clothing and shoes. 

For more information, ask your doctor about stress testing.