What is bradycardia and how does it affect the body?

Bradycardia is an abnormally slow heart rate of less than 60 beats per minute. A normal heartbeat is between 60 and 100 beats per minute. However, many otherwise healthy people and those taking heart or blood pressure medications often have heart rates in the 50s without symptoms. Some people even have heart rates in the 40s at rest or with sleeping, especially elite athletes. But a slow heart rate can also be due to a heart problem that can cause fatigue, weakness, lightheadedness, shortness of breath and fainting.