A heartbeat is the rhythmic contraction and relaxation of the heart muscle, which pumps blood throughout the body. This process is essential for delivering oxygen and nutrients to tissues and removing waste products. The heartbeat is typically measured in beats per minute (BPM) and can vary based on factors like age, fitness level, and emotional state. The heart has four chambers: the left atrium, right atrium, left ventricle, and right ventricle. Electrical signals from the sinoatrial (SA) node initiate each heartbeat, ensuring a coordinated and efficient flow of blood. Monitoring heart rate is important for assessing overall health and detecting potential medical issues.