Premature ventricular contractions, or PVCs, can occur at any time, and are generally considered benign. However, it can be physically and psychologically stressful to experience PVCs during exercise. Understanding why they occur and when or if to seek medical attention can make a positive difference in your attitude toward exercise.
How Hearts Beat
Hearts have two sides: right and left. They have upper chambers on each side, called the atria. The lower chambers on each side are the ventricles. Upper and lower chambers are connected by valves that open and close during heartbeats. The atria fill with blood, the valves open and let the blood into the ventricles, the valves close, and then the ventricles squeeze shut and pump out blood to the rest of the body. This happens anywhere from 50 to 180 times per minute depending on activity level.
The Heart Can Correct Itself
Heart contractions are triggered by electrical activity in the heart's natural pacemaker, the SA node. PVCs happen when extra electricity goes to the ventricles, so they squeeze too soon. Since the ventricles pushed the blood out before filling completely, your body wants more blood sent. Because your heart is built from different types of muscle cells and connective tissue, it turns out that skipping a beat right after a PVC will almost always fix the problem. This a natural corrective system that evolved in humans.
PVCs During Exercise
When PVCs happen during exercise, you may feel dizzy, feel your heart race or skip a beat. Sometimes exercisers will cough and this will stop the PVCs. Beginning exercisers may have PVCs, and it will resolve as you get into better shape. Experienced exercisers can have this happen too, especially coming off illness or a prior hard workout. Human beings are not robots and have different performance levels on different days. Healthy individuals with no heart disease that have occasional PVCs during a workout should not worry.
When to See your Doctor
PVCs that run continuously can result in tachycardia, the heart beating too fast, and cause dizziness and fainting. There are underlying problems that can cause PVCs during rest and during exercise. If you have a health condition like obesity, high blood pressure, prior heart problems, diabetes, or you smoke, see your doctor. Many times the PVCs will go away as these more serious conditions are treated.