The heart is responsible for pumping blood and nutrients throughout the body to sustain life. In a normal individual, the sinus rhythm, or how fast the heart beats, is regulated by the sinoatrial node, located inside the section of the heart referred to as the atrium. Sinus bradycardia is a medical condition where the sinus rhythm is disturbed, causing the heart to beat slower than usual when at rest.
In an average adult, the sinoatrial node acts as the body’s natural pacemaker and sends out electrical impulses causing the heart to beat around sixty to one hundred times every minute. When these impulses slow and the heart rate dip below fifty beats per minute, the individual is considered to have sinus bradycardia. Though many athletes in peak physical condition sustain a resting heart rate under fifty beats per minute, sinus bradycardia in an average person can cause symptoms and problems if the heart rate decreases too much so as to not meet the body’s needs. Due to some athletes' training though, their heart becomes more efficient, being able to pump enough blood out to the body with less beats per minute.
In some cases of sinus bradycardia, there are no outwards signs of a problem. When problems do arise however, symptoms may include respiratory problems such as an inability to endure any increases in physical activity, and shortness of breath with feelings of dizziness or lightheadedness, a condition known as vertigo. Chest pain and an increasing chance of fainting, a medical condition referred to as syncope, may also result as the body is not receiving an adequate amount of blood.
The most common causes of sinus bradycardia can include such things as a slow-functioning thyroid or sleep problems including sleep apnea, a temporary stoppage of breathing during sleep. Some medications may also contribute to slowing of the heart rate. The sinoartrial node may also exhibit problems related to a disease process often referred to as sick sinus syndrome. This is where the normal functioning of the sinoatrial node is disrupted, slowing the resting heart rate.
Treatment for sinus bradycardia includes making healthy lifestyle choices including regular exercise and proper diet. In extreme cases, administering oxygen temporarily can combat the decrease in oxygen delivered by the lack of adequate heart pumping. In long-term or chronic cases, certain medications might be able to stabilize the rate of heart contracts. Surgical procedures include the placement of a pacemaker to control the pace at which the heart beats.