Bradycardia is a slow heart rate. It often does not cause symptoms. If symptoms occur, they may include fatigue, lightheadedness, and exercise intolerance.

Symptomatic bradycardia is a slow heart rate — less than 60 beats per minute — that may cause a person to experience a range of symptoms. Most people with bradycardia have no symptoms. However, some will experience symptoms such as exercise intolerance, fatigue, and trouble breathing.

Bradycardia may occur more often in young athletes and older adults and during sleep. A slow heart rhythm may originate from the sinus node, the atrioventricular nodal tissue, and the specialized His-Purkinje conduction system. These components send electrical signals into the heart muscle and control the heart rate.

A slow heart rate in young people or athletes or during sleep is often benign and does not require treatment if a person has no symptoms. However, older people who experience symptomatic bradycardia may need treatment.

This article explores the symptoms, causes, diagnosis, and possible treatments for symptomatic bradycardia.

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Most people with bradycardia, including younger athletes, do not experience symptoms. If symptoms occur, they may include:

These symptoms develop when a person’s heart rate becomes too slow, preventing the heart from pumping enough blood to support important functions in other organs, such as the brain, and in the heart itself.

Complications of bradycardia can include frequent fainting, heart failure, and cardiac arrest.

Though some symptoms may go unnoticed, a person should go to the emergency room or call 911 if they experience:

Several conditions and issues may lead to bradycardia.

Some people may have a higher risk of developing symptomatic bradycardia, including those who:

A 2016 review suggests that a person may inherit certain genes that may put them at risk of developing bradycardia. However, it is not clear exactly how these genetic connections work, and further research is necessary.

A person may be able to tell that their heart rate is slow. They may do this by counting their pulse for 1 minute. A more accurate option may be to use a wearable heart rate monitor such as a smartwatch or a chest strap.

People should consult a doctor if they think their heart rate is slow or if they experience symptoms of bradycardia. In order to diagnose bradycardia, a doctor will need to assess a person’s heart rhythm. They may use several tools, including:

A doctor may perform a physical exam and review a person’s medical history and medications.

Healthcare professionals may also order blood tests to help them determine whether an electrolyte imbalance, a thyroid stimulating hormone imbalance, or another issue may be contributing to someone’s bradycardia.

They may order additional tests to check for possible infections or other underlying causes. These can include:

Treatment will depend on what healthcare professionals find during diagnosis.

People with severe types of bradycardia, such as complete heart block, may benefit from a pacemaker. In a 2018 report, experts noted that doctors implant around 1 million pacemakers to treat bradyarrhythmias every year.

A doctor may review a person’s medications. If they suspect that a medication may be the cause, they may recommend that the person switch medications to help improve their bradycardia.

Finally, a doctor may recommend treatment of any other underlying condition a person has.

A person may also take steps to improve their heart health with guidance from their doctor, such as:

A doctor can help monitor a person’s heart rate and provide additional recommendations for treatment.

Symptomatic bradycardia is a slow heart rate that causes a person to experience various symptoms due to the decreased beats per minute.

A slow heart rate can cause several potential symptoms, such as fatigue, slowed thinking, and difficulty with exercise.

Diagnosis typically requires an EKG or another form of monitoring. A doctor may recommend other tests to identify the causes of someone’s bradycardia.

Once a doctor diagnoses bradycardia and identifies its possible cause, they will take steps to treat it, which may include changing a person’s medications and treating any underlying conditions.

With a doctor’s guidance, a person may also make lifestyle changes to help improve their heart health. These may include regular exercise, weight management strategies, and a nutritious diet.