Heart rate is a term that describes the average number of times your heart pumps blood to your body in a single minute. Your body naturally tries to keep this rate within a certain range, and the consistent presence of an abnormally low or high number of beats can significantly endanger your health. Several factors collectively determine your ability to exert efficient heart rate control.
Basic Control
The basic rhythm and rate of your heartbeat are controlled by the sinoatrial node, or SA node, a grouping of specialized cells located in the right chamber of your upper heart, called the right atrium. This node produces electrical signals that travel from your upper heart to the pumping chambers, called ventricles, in your lower heart. When the ventricles receive a signal from the SA node, they contract and pass the blood inside them to your body and lungs through your blood vessels. When any given SA node signal stops, your ventricles stop pumping, relax and fill up with blood for the next contraction, according to the National Heart Lung and Blood Institute, or NHLBI.
Heart Rate Influences
In periods of physical inactivity, normal heart rates for adults range from about 60 to 100 beats per minute. Athletes and others in top condition may have heart rates as low as 20 beats below this average, according to the National Institutes of Health's MedlinePlus website. Factors known to affect or alter your normal resting heart rate include your body size, emotional state, current body position, pattern of medication usage, overall fitness and current or recent level of physical activity. Your resting rate is also affected by the air temperature in your local environment, notes MayoClinic.com.
Arryhthmias
If the electrical signal from your SA node to your ventricles is altered in any way, you can develop some form of a heart rhythm disorder called an arrhythmia. Depending on your circumstances, an arrhythmia can affect either your upper or lower heart. Potential factors in the development of arrhythmia include smoking, use of drugs such as amphetamines or cocaine, heavy alcohol intake, excessive caffeine use and extreme stress or anger. Medical conditions known to promote heartbeat irregularities include hypertension, abnormally low or high thyroid output, heart attack, heart failure and coronary artery disease, according to the NHLBI.
Considerations
While most arrhythmias do not cause serious problems, some can indicate dangerous changes in your heart health. A heart rate that consistently exceeds 100 beats per minute is a potential sign of a medically significant condition called tachycardia. A heart rate that consistently falls below 60 beats per minute is a potential sign of another medically significant condition, called bradycardia. Potential basic symptoms of arrhythmias include a fluttering or obviously irregular heartbeat, as well as clear pauses between heartbeats. Potential symptoms of more serious problems include chest pain, fainting, shortness of breath, dizziness and anxiety. Consult your doctor if you experience these symptoms.
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