B1. Bradycardia


Very simply, bradycardia is a medical term for a slow heart rate.

Most adult hearts beat between 50 and 100 times per minute at rest. If you have bradycardia, your resting heart rate is slower than usual — beating fewer than 50 times per minute.

Bradycardia can be harmless, but in some cases it can be life-threatening. For certain people — mostly young adults and trained athletes — a slow heart rate is normal and doesn’t cause any symptoms or health problems. For others, bradycardia can cause symptoms, such as dizziness or fainting, which should be looked into and treated. That’s when the body isn’t getting the oxygen it needs because the heart’s pumping action is slowed.

Keep reading to learn more about bradycardia, how to manage it, and questions to ask your doctor.

Understand Your Condition

What is Bradycardia?

Bradycardia is a type of heart rhythm disorder. It happens when someone’s heart rate falls below 50 beats per minute, which is slower than normal.

The heart’s electrical system controls when the heart contracts and pumps blood out to the body. If you have bradycardia, these signals are sluggish, or they become blocked in some way.

Bradycardia can be caused by:

  • Sinus node dysfunction:The heart’s natural pacemaker isn’t working properly.
  • Heart block:The electrical connection between the upper and the lower chambers of the heart doesn’t work as it’s supposed to. This causes the lower chamber that pumps blood out of the heart to beat slowly.

In some instances, a slow heart rate is normal. For example, being very athletic and physically fit can lead to the heart pumping more efficiently so it doesn’t need to beat as many times a minute to meet the body’s needs. Your heart also tends to naturally beat more slowly during sleep.

Signs and Symptoms

For some people, a slow heart rate is normal and never causes any symptoms.

But if your heart beats slowly enough that your brain and other organs don’t get enough oxygen and nutrients, your body may quickly tell you something is awry.

Symptoms may include:

  • Feeling dizzy, weak or lightheaded
  • Fainting
  • Tiring easily
  • Being short of breath, especially with exertion
  • Confusion or difficulty focusing
  • Heart palpitations or flutters
  • Limited ability to exercise
  • Chest pain, which may signal reduced blood flow to the heart

Call 112 if you experience:

  • Shortness of breath
  • Pain or pressure in the chest
  • Feeling lightheaded, dizzy or faint

It’s very important to tell your doctor how you’re feeling — even if symptoms are mild. The way a slow heart rate affects your ability to do things will help determine if and when you need a pacemaker or other advanced treatment. These symptoms could also be caused by aging or other medical conditions such as anemia or hypothyroidism (a thyroid that doesn’t produce enough thyroid hormone).

If untreated, bradycardia can lead to complications, including congestive heart failure, stroke and, in some cases, sudden death. So if you have concerns, speak up.

What Increases Your Risk?

Many factors can affect how fast or slow your heart beats. For example, your:

  • Age
  • Activity level
  • Sleep (the heart beats slowly during sleep)
  • Imbalance of electrolytes, such as low potassium levels (minerals need to be at the right levels for the body to work properly)

You are at greater risk for developing bradycardia if you:

  • Are 65 or older.The heart’s electrical system can become damaged as we age, making older people especially prone to slower heart rates.
  • Have some heart disease or heart damage.For example:
    • Coronary artery disease
    • Previous heart attack
    • Issues with how your heart’s electrical system is working (left bundle branch block causes a delay in how electrical signals are sent from the upper to lower chambers of the heart)
    • Congenital heart disease (for example, being born with a hole in the heart)
    • Infection (myocarditis)
    • An inflammatory disease that affects cells (sarcoidosis)
  • Have had heart surgery.It can be a complication of some heart procedures (for example, bypass, valve replacement, TAVR and others).
  • Have untreated high blood pressure.
  • Take certain medications.For example, beta-blockers, calcium channel blockers, certain antidepressants.
  • Have other medical conditions.For example, sleep apnea, low thyroid function (hypothyroidism), certain neurologic disorders (epilepsy) or excessive alcohol or recreational drug use.
  • Have family history of a slow heart rate.

Research shows that Lyme disease can also affect the heart’s electrical system and cause heart block, which may make bradycardia more likely.

Talk with your doctor if you:

  • Are over age 65
  • Know of someone in your family with heart rhythm problems
  • Notice any of these symptoms, even if mild
  • Have noticed a change in your heart rate
  • Suspect you had a tick bite or may have Lyme disease

Exams and Tests

Bradycardia is most often suspected based on a report of symptoms, by taking your pulse, or both.

Your health care provider may recommend additional tests to confirm that you, in fact, have bradycardia. Further tests also can help determine its cause. These tests may include:

  • Electrocardiogramto measure and produce tracings of your heart’s electrical activity. However, this test is limited in that you would have to be having an episode of a slow heart rate while the test is being done.
  • Holter monitor(a portable wearable monitor) to record your activity level and heart rhythm, usually worn for 24 to 72 hours.
  • Heart rate monitorson certain wearable smart watches, but talk with your clinician first.

Your health team will also consider and try to rule out other conditions that might be contributing to a slower heart rate. For example, sleep apnea — a sleep disorder that results in shallow or pauses in breathing — can cause bradycardia due to a lack of oxygen.


Treatment will depend on how slow your heart rate is, what might be causing it and any complications. In some cases, bradycardia can result in fainting episodes, dangerous falls or even seizures and sudden death due to long pauses between heartbeats.

Some people may not need to do anything for their slow heart rate. For others, treatments may include:

  • Treating an underlying condition(s)
  • Adjusting or changing medications that may be causing dips in heart rate.
  • Pacemaker (usually if there is irreversible damage to the heart’s electrical system and in older people)

Lifestyle changes are key for managing any heart condition.

Your goals for treatment matter, too. Be sure to tell your doctor about your values and what you prefer for treatment.

Simple Steps to Take Your Pulse

It’s a good idea to be able to check how many times your heart beats each minute.

Here are some quick tips on taking your own pulse. You can also ask your clinician to show you how to take it.

  1. Extend one arm with the palm of your hand facing up.
  2. Use your first (index) and middle fingers on your other hand to press the inside of your wrist near the base of your thumb (just below the palm of your hand).
  3. Press lightly until you can feel the beating of your pulse.
  4. If you have trouble finding it, try pressing a little harder or adjust where you are pressing.
  5. Once you can feel your pulse consistently, look at a clock and count the number of pulses you feel in 10 seconds. Take that number and multiply it by 6.

Remember that your heart rate is affected by what you’re doing (for example, resting or exercising). You should ideally rest before taking your pulse.

Protect Your Heart

Bradycardia is a heart rhythm disorder. In many cases, it can stem from another heart issue or damage to the heart. While there are no specific steps to prevent bradycardia, it’s a good idea to keep your heart healthy by:

  • Eating a heart-healthy diet
  • Getting regular exercise
  • Knowing your cholesterol and blood pressure numbers and keep them under control
  • Avoiding smoking and secondhand smoke
  • Limiting alcohol intake
  • Keeping stress levels in check
  • Reporting any changes to your health care providers