Bradycardia (Slow Heart Rate) Signs, Causes, and Risk Factors

Considered an abnormal heart rhythm, bradycardia (or a slow heart rate) can be caused by many factors — some of them good ones! Let’s look at why you may experience bradycardia.


Bradycardia is the medical term for a slow heart rate (also called “pulse rate”). In adults, the heart normally beats between 60 and 100 times per minute. When the heart beats faster than that, it’s called “tachycardia.” When the heart beats fewer than 60 times per minute, we call it “bradycardia.”

A slow heart rate alone is not cause for concern. In fact, virtually all highly fit people, such as triathletes, naturally have a slow resting pulse rate. That’s because your heart rate goes down as your cardiovascular system becomes more efficient.

Bradycardia can be a problem if it happens due to underlying heart disease or other conditions. Let’s look more closely at what can cause a slow heart rate.


Like we said earlier, a slow pulse rate can be normal if you’re a very active, athletic person. However, bradycardia can occur for variety of unhealthy reasons, including:

  • Problems with the heart’s “pacemaker cells”
  • Abnormal levels of potassium or other minerals in the blood
  • Damage to the heart muscle from a previous heart attack
  • An enlarged heart
  • Congestive heart failure
  • Heart valve problems
  • Certain medications
  • Issues with the endocrine system (especially thyroid problems)

And that’s just the short list. Often, you won’t need treatment if your bradycardia is not accompanied by other symptoms (shortness of breath, for example) or if your heart rhythm is not otherwise abnormal. Your health care provider will determine what type of treatment you need, if any, for your bradycardia.


Bradycardia can happen to anyone. In general, you may be at higher risk of bradycardia if you fall into one of these categories:

  • You’re extremely fit or athletic
  • You take medication designed to slow your heart rate (such as beta blockers)
  • You take antidepressant medication
  • You take narcotic medications to treat chronic pain
  • You use certain illicit or recreational drugs
  • You have thyroid or endocrine problems
  • You previously experienced a heart attack
  • You have congestive heart failure


As we’ve said, sometimes bradycardia — on its own — isn’t treated at all. Many people can tolerate a pulse rate as low as 50 beats per minute without experiencing symptoms. When bradycardia is caused by problems with the heart’s pacemaker cells, then the usual treatment is to implant a permanent pacemaker device.

These devices have become quite sophisticated over the years, and today’s pacemakers often don’t “kick in” unless your heart rate falls below a certain threshold. For instance, if your heart rate falls below 50 beats per minute, then the pacemaker sends an electrical impulse that causes the heart to beat faster. Pacemakers are considered a safe and effective treatment for certain types of bradycardia.

If your bradycardia is caused by medications, your health care provider may change your dosage or change your medication entirely.

When bradycardia is caused by a different underlying condition, such as thyroid problems, then your health care provider will address the underlying condition. This should cause your heart rate to return to normal.

In general, treatment for your bradycardia will be specific to the cause. And as you’ve seen, many things can cause a slow heart rate.


If you experience non-emergency symptoms that could be heart-related, you should see your health care provider by appointment. However, if you experience the signs of a heart attack, you should seek emergency medical care. Signs of a heart attack include:

  • Intense chest pain that feels like tightness and/or squeezing
  • Chest pain that radiates into the lower jar or left arm
  • Intense pain at the mid-back (this sign occurs more often in women than men)
  • Shortness of breath
  • Heart palpitations
  • Sweating
  • Fainting
  • Nausea and/or vomiting

If you experience these symptoms or witness someone else in cardiac distress, call immediately for emergency responders.


If you’ve been diagnosed with bradycardia, know this: It’s highly treatable. Many patients with bradycardia receive treatment that enables them to continue living a long, healthy, active lifestyle.