Bradycardia: The Hidden Danger Behind Slow Heartbeats

After a light jog, you check your heart rate at smartwatch . The number 48 bpm appears on the screen, slower than usual. This may indicate bradycardia, the medical term for a heart rate that is slower than normal.

Most adults have a resting heart rate between 60–100 beats per minute. If the number is below 50 beats per minute, that is what doctors call bradycardia. A slow beating heart does not always cause symptoms, but that does not mean it is harmless.

For those who regularly train hard—such as marathon runners, long-distance cyclists, or swimmers—the numbers 40–50 bpm can be normal, indicating an efficient and well-trained heart. They rarely feel any discomfort even though their heart rate is "slower." However, if you are not a trained athlete, a slow heart rate can cause dizziness, fainting, or shortness of breath. This is a sign that the body is not getting enough oxygen because the heart cannot pump blood quickly enough. If you have ever experienced such symptoms, it's best to see a doctor.

What is actually bradycardia? Is a slow heart rate always dangerous? Scroll down to read!

1. Type

• Sinus bradycardia

When the sinus node continues to function, but the heart rate slows down below 60 beats per minute, it is called sinus bradycardia. For many athletes or people who regularly exercise, a rate of 50–60 bpm is actually a sign of an efficient heart, so treatment is usually not needed unless there are symptoms. If the rate is below 40 bpm, the doctor may refer to it as bradycardia" junctional because the impulse source can move to other areas.

• Sinus pause ( sinus arrest )

Imagine the heartbeat suddenly "pauses" for a moment because the sinus node does not trigger contraction. That is sinus pause. If this break happens only occasionally, maybe you won't feel anything. However, if it happens frequently or lasts too long, you may experience dizziness, blurred vision, or an increased risk of complications.

• Sick sinus syndrome

If the sinus node itself is problematic, the result can vary: the heartbeat may be too slow, too fast, or alternate between the two. This condition is called sick sinus syndrome. The symptoms can be mild, but sometimes require special handling to restore the heart rhythm.

• Tachy-brady syndrome

This type of bradycardia often occurs in patients with atrial fibrillation, caused by damage to the sinus node. This condition causes the heart rate to alternate between too fast and too slow. Symptoms may include palpitations, dizziness, or fainting. It can also lead to complications and a higher risk of stroke.

• Heart block ( heart block )

In the case of heart block, the electrical signal from the sinus node is blocked before reaching the entire heart muscle. As a result, the heartbeat becomes delayed or irregular. The severity of the block can vary, ranging from causing only minor disturbances to requiring a pacemaker.

2. Causes

Some causes of bradycardia include:

• Problem with the sinoatrial (SA) node, the natural pacemaker of the heart.

• Problem in the electrical conduction pathway of the heart that blocks the signal from the atrium to the ventricle.

• Metabolic disorders such as hypothyroidism (low thyroid hormone).

• Heart damage caused by aging, heart disease, or a heart attack.

• Side effects of some heart medications that can slow the heartbeat.

• Congenital heart defect.

• Infection of the heart muscle (myocarditis).

• Postoperative heart complications.

• Electrolyte imbalance in the blood, such as abnormally low or high levels of potassium or calcium.

• Recurrent breathing disorders during sleep ( obstructive sleep apnea )

• Inflammatory diseases such as rheumatic fever or lupus.

3. Symptoms

Sometimes a slow heart rate is normal and does not cause any symptoms. However, when your heart rate is so slow that the brain and other organs do not get enough oxygen or nutrients, your body will immediately send signals.

Symptoms of bradycardia can include:

• Feeling dizzy, weak, or lightheaded.

• Pingsan.

• Easy to get tired.

• Shortness of breath, especially during activities.

• Confusion or difficulty focusing.

• Heart is pounding.

• Limitation of physical activity ability.

• Chest pain, which may indicate reduced blood flow to the heart.

If you experience severe shortness of breath, chest pain/pressure, or nearly fainting, call emergency services immediately.

Tell the doctor all the symptoms you are experiencing, even if they seem mild. This information helps determine the next steps in treatment. Also remember, those symptoms could appear due to aging, anemia, or an underactive thyroid.

Without treatment, bradycardia can develop into heart failure, stroke, or even sudden death. Therefore, don't hesitate to consult a doctor if you feel worried.

4. Diagnosis

See a doctor or go to the nearest emergency unit immediately if you experience chest pain, confusion, or loss of consciousness.

If your heart rate is less than 60 bpm and you have any symptoms, see a doctor. Recording when your heart rate is slow and what you feel at that time can help.

For diagnosis, the doctor will ask about your symptoms, medical history, and family history. Also, tell the doctor if there are any factors that trigger or alleviate the symptoms you are experiencing. The doctor will also ask about your lifestyle and medications currently being used.

In addition, the doctor will examine and measure your heart rate, and listen to it with a stethoscope. Additional tests may be required, such as:

• Electrocardiogram (EKG)

• Heart monitoring device that records your heart rate at home.

• Your blood.

The doctor may refer you to a heart specialist for further tests and treatment.

5. Handling

The management of bradycardia depends on its cause. If you are not experiencing any symptoms, you may not need specific treatment.

If there are other diseases that cause bradycardia, such as hypothyroidism (underactive thyroid gland), the doctor will treat the disease so that the heart rate can return to normal.

If the medication you are taking affects your heart rate, the doctor may recommend stopping or replacing the medication. However, do not stop or change the medication without first consulting your doctor.

Emergency handling

If you suddenly experience bradycardia with severe symptoms, you need immediate treatment. Doctors can administer specific medications or use a temporary pacemaker to stabilize your heart rate.

Long-term handling

Some people with bradycardia need long-term management with a pacemaker ( Pacemaker ) or defibrillator This device is implanted under the skin through a brief procedure, usually does not require general anesthesia and sometimes patients can go home the same day or only need a one-night hospital stay.

After the procedure, you may need to limit your activities for several weeks. The doctor will explain about:

• What happens during the procedure.

• Benefits and risks of procedures and the use of pacemakers or other devices.

• What activities need to be limited after the procedure, including driving, traveling, and sports.

• Check-up schedule with the doctor.

6. Possible complications

Possible complications resulting from bradycardia include:

• Heart failure.

• Often faints (syncope).

• Cardiac arrest (in extreme cases).

7. Prevention

The best way to prevent bradycardia is to maintain heart health so that you do not get heart disease. You can take these steps:

• Regular health check-ups.

• Take the medicine as prescribed by the doctor, do not stop or change it on your own.

• Exercise regularly.

• Eat low-fat, low-salt, and low-sugar foods, and increase the intake of fruits, vegetables, and whole grains.

• Maintain ideal body weight.

• Control blood pressure and cholesterol levels.

• Do not smoke or quit smoking immediately.

• Do not drink alcoholic beverages.

If you already have heart disease, these steps can be taken to reduce the risk of bradycardia:

• Follow the doctor's treatment plan diligently.

• Report to the doctor immediately if new symptoms appear or there is a change in condition.

Bradycardia means a heart rate of less than 60 beats per minute. For some people, this does not cause any problems or symptoms. However, if symptoms such as chest pain, shortness of breath, or severe dizziness appear, it is best to go to the emergency room immediately. Doctors can treat bradycardia by replacing the medication that causes it. If necessary, the doctor will install a heart pacemaker, which can be temporary or permanent. The best way to prevent it is to take good care of the heart.

Reference

"Bradycardia." Johns Hopkins Medicine Accessed July 2025.

"Bradycardia." American College of Cardiology Foundation Accessed July 2025.

"Bradycardia: Slow Heart Rate." American Heart Association Accessed July 2025.

"Bradycardia: Causes, Symptoms, Treatment." WebMD Accessed July 2025.

"Bradycardia." Healthdirect Accessed July 2025.

Frequent Palpitations Can Be a Symptom of Arrhythmia? This Is What the Doctor Says 7 Ways to Lower Your Heart Rate While Running How to Know the Fetus's Heartbeat with Hands, Is It Possible?