When taking a history, a health care provider must include relevant questions that help narrow down the differential, such as any recent medication changes, medication overdoses, chest pain, shortness of breath, history of prior myocardial infarction, symptoms of intermittent palpitations, history of chest trauma, rash or recent tick bite, current or past diagnosis of streptococcus pharyngitis, family history of sinus bradycardia, family history of muscular dystrophy. Those who present with symptoms may present with fatigue, exercise intolerance, lightheadedness, dizziness, syncope or presyncope, worsening of anginal symptoms, worsening of heart failure, or cognitive slowing. Using history to relate to the symptoms of a patient with sinus bradycardia on an electrocardiogram is essential to come to the correct diagnosis. Also, patients above the age of 65 tend to have sinus bradycardia during sleep secondary to the aging of the sino-atrial node. Healthy young adults and athletes tend to have an increased vagal tone which keeps them in sinus bradycardia at rest. The majority of patients with sinus bradycardia do not have symptoms.