What does bradycardia refer to?

Bradycardia refers specifically to a condition where an individual's heart rate is slower than normal, typically defined as fewer than 60 beats per minute. This condition can occur for various reasons, including the influence of medications, underlying health conditions, or as a natural response in well-conditioned athletes where the heart becomes more efficient. Understanding the range of normal heart rates is essential in differentiating bradycardia from other heart rate conditions, such as tachycardia, which indicates a fast heart rate, or sinus rhythm, which is characterized by a normal heart rate.

In the options presented, the definition of bradycardia aligns perfectly with the description of a slow heart rate under 60 beats per minute, making it the correct choice.