A heart rate that is too slow is called bradycardia. In some cases, it may seem like the heart is skipping a beat from time to time. The heart rhythm of well-trained athletes may be very slow without any underlying health problem as their hearts are more efficient than the hearts of non-athletes. They are able to pump the same amount of blood into the body with fewer heartbeats. If the heart rate fails to supply the body with the needed blood and oxygen, bradycardia can be a severe health issue. In some types of bradycardia, the blood supply is sufficient at rest, but the heart rate isn´t able to adapt to situations of physical or emotional stress. This failure to adapt the heart rate is known as chronotropic incompetence.