Heart arrhythmia is an abnormal rhythm or rate of the heartbeat. It can cause the heart to beat an irregular rhythm, beat too quickly or beat too slowly. Although exercise is typically good for the heart, it can sometimes trigger arrhythmia episodes in some people. Because heart arrhythmias can sometimes signal a dangerous condition, it is important to understand why they can occur during exercise and how they can be treated.
Outward signs are not always present during arrhythmia episodes. However, the National Heart, Lung and Blood Institute notes that it is common to experience a slowed heartbeat, pauses between heartbeats, the sensation of your heart fluttering or skipping, a pounding heart, anxiety, difficulty breathing, sweating, weakness and pain in the chest. You can also become dizzy or lightheaded during exercise-related arrhythmias, which can lead to fainting episodes.
The competition involved with some types of exercise, such as competitive sports, can cause the body to go into a "flight-or-fight" mode, which can interfere with the heart electrically, causing heart arrhythmias. In addition, the stress of excessive or intense exercise can make the body work harder and raise the blood pressure, which can release stress hormones and trigger arrhythmias. Consuming nicotine or caffeine before or after exercise can also lead to episodes. Some medical conditions such as coronary heart disease, Wolff-Parkinson-White syndrome and underactive thyroid can also cause arrhythmias during or after exercise.
Do not overexert yourself during exercise; take breaks as needed, particularly if you feel your heart behaving abnormally. Cool down by gradually reducing your activity after exercise to slowly return your heart rate back to a normal pace. For example, take a gentle 10-minute walk and stretch. If a certain type of exercise causes heart arrhythmias, discontinue it. Avoid caffeinated beverages or foods and stop smoking. Chronic heart arrhythmias may require an antiarrhythmic medication to help control episodes.
Never ignore heart arrhythmias, particularly if they are painful or chronically occur during or after exercise. See a doctor who can prescribe medication, surgically repair the problem or insert a pacemaker. Left untreated, heart arrhythmias can prevent blood from pumping effectively throughout the body, resulting in a serious medical condition such as a stroke, blood clot or even heart failure.