Bradycardia refers to a slower than normal heart rate, typically defined as fewer than 60 beats per minute in adults. It can be a normal finding in athletes or during sleep, but may also indicate underlying health issues, such as Heart disease, electrolyte imbalances, or complications from medications. Symptoms can include fatigue, dizziness, or fainting, and treatment depends on the cause and severity of the condition. In some cases, a pacemaker may be required to regulate the heart rate.