Symptoms of bradycardia typically occur when the heart rate falls below what threshold?

Bradycardia is defined as a slower than normal heart rate, specifically when the heart beats fewer than 60 times per minute. Symptoms of bradycardia often manifest when the heart rate drops below this threshold. At rates below 50 beats per minute, the heart may not pump sufficient blood to meet the body's needs, potentially leading to symptoms such as dizziness, fatigue, shortness of breath, or even fainting. This physiological response is due to the inadequate blood flow to vital organs, which can occur at heart rates significantly below the normal resting rate for adults, typically between 60 and 100 beats per minute. Thus, the threshold for symptoms of bradycardia is correctly identified as being at or below 50 beats per minute.