Bradycardia, or a slow heart rate, has several causes including aging, diseases and medication, explains WebMD. A slower-than-normal pulse rate can be healthy, especially in very fit people such as athletes.
Bradycardia, a type of arrhythmia, is caused by the heart's electrical conduction system, according to MedlinePlus. When the system has problems, abnormal or extra signals may occur, and signals can be blocked or slowed. Sometimes electrical signals travel in pathways through the heart that they aren't supposed to. A common cause as to why the conduction system is malfunctioning is due to abnormal levels of potassium or other substances in the body. Another cause is a damaged heart muscle or a congenital heart defect.
Heart failure, an enlarged heart and an overactive thyroid gland are also common causes of bradycardia, MedlinePlus explains. External causes include alcohol, caffeine or stimulant drugs taken in excessive amounts. Some heart, blood pressure and depression medicines also cause arrhythmia.
The heart can also change as a result of aging, which can cause bradycardia, according to WebMD, Lifestyle causes are also responsible for heart rate issues and can be prevented with a healthy diet, being active, losing weight, not smoking and managing health problems such as high blood pressure.