Bradycardia is when your heart beats fewer than 60 times per minute while you’re at rest. It may cause no symptoms, but if blood flow to the body drops, you can develop tiredness, weakness, or dizziness.
In some people, bradycardia is physiological, meaning it isn’t a sign of disease. This can happen naturally in high-performance athletes and in older adults.
In other cases, bradycardia can point to a health problem, such as heart disease or hypothyroidism. If symptoms appear, it’s recommended to see a cardiologist for testing, to identify the cause, and to start the most appropriate treatment, which may include a pacemaker.
Main symptoms
The main symptoms of bradycardia are:
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Easy fatigue or weakness;
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Dizziness or vertigo;
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Chest pain with a burning or tight sensation;
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Confusion or fainting;
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Cold skin;
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Malaise.
Bradycardia often causes no symptoms. However, according to the American Heart Association, when the heart rate becomes very slow, blood flow to the body and brain can drop and lead to symptoms like fatigue, dizziness, shortness of breath, or fainting.
For this reason, it’s important to see a cardiologist if bradycardia causes symptoms or occurs often. The specialist can confirm the diagnosis and recommend the most suitable treatment.
Severe bradycardia
Bradycardia can become serious if it causes symptoms or occurs often, as it may limit the amount of oxygen reaching the brain and other organs.
According to the American Heart Association, severe chest pain, difficulty breathing, or unconsciousness are medical emergencies and warrant calling 911 for urgent care.
How to identify
If you want to check whether your heart rate is normal and whether you may have bradycardia, enter your information in our calculator.
To measure your heart rate, place your index and middle fingers on the side of your neck above the collarbone. Count the beats you feel for 1 minute.
To get results that better reflect real-life conditions, you can use a heart rate monitor that attaches to your finger, a digital blood pressure monitor that also displays heart rate, or a pulse oximeter, which measures blood oxygen levels and heart rate.
It’s important to note that the calculator is only a guidance tool. It does not replace an evaluation by a cardiologist or a primary care provider.
Confirming a diagnosis
A cardiologist diagnoses bradycardia by reviewing a patient’s symptoms and medical history, and by performing a physical exam that involves listening to the heart and checking the heart rate with a stethoscope.
They may also order more specific tests, such as an electrocardiogram (ECG), an echocardiogram, or an exercise stress test.
A 24-hour Holter monitor may also be used to see whether bradycardia is controlled or whether there are episodes of heart block during the 24-hour period.
In some cases, the clinician may order blood tests to check for causes such as infection, hypothyroidism, or changes in electrolytes like calcium or potassium.
Possible causes
The main causes of bradycardia include:
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Heart conditions, such as sinus node disease, atrioventricular (AV) block, heart attack, or congenital heart defects;
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Hypothyroidism or hypoglycemia;
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Low potassium or calcium levels in the blood;
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Medications for high blood pressure or arrhythmias;
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Exposure to toxic substances, such as nicotine;
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Meningitis, tumors in the central nervous system, or increased intracranial pressure;
Less commonly, bradycardia can happen due to viral or bacterial infections, such as diphtheria, rheumatic fever, or myocarditis. Myocarditis is inflammation of the heart muscle that can be caused by viral or bacterial infection.
Physiological bradycardia
Bradycardia can be considered normal (physiological) when it happens during sleep. It can also be normal in people who exercise regularly, such as runners and cyclists, because the heart adapts to routine training and may beat more slowly at rest.
It can also happen after a large meal or during blood donation. In these situations, it typically improves after a few hours.
Treatment options
Treatment for bradycardia should be guided by a cardiologist and depends on the cause, symptoms, and severity.
If bradycardia is related to another condition, such as hypothyroidism, treatment is usually done with medications such as levothyroxine. Treating hypothyroidism appropriately can resolve bradycardia.
In more severe cases, a pacemaker may be needed. A pacemaker is surgically implanted to help regulate the heart rate in bradycardia.