Bradycardia | Slow Heart Rate

Updated:Oct 26,2016

Bradycardia = too slow

View an animation of bradycardia Aheart rate of less than 60 beats per minute (BPM) in adults is called bradycardia. What's too slow for you may depend on your age and physical condition.

  • Physically active adults (and athletes) often have a resting heart rate slower than 60 BPM but it doesn't cause problems and is normal for them.
  • Your heart rate may fall below 60 BPM during deep sleep.
  • Elderly people are more prone to problems with a slow heart rate.

View an animation of bradycardia.

Causes of bradycardia

  • Problems with the sinoatrial (SA) node, sometimes called the heart's natural pacemaker
  • Problems in the conduction pathways of the heart (electrical impulses are not conducted from the atria to the ventricles)
  • Metabolic problems such as hypothyroidism (people with low thyroid hormone)
  • Damage to the heart from heart attack or heart disease (myocardial infarction or MI)

Symptoms of bradycardia

A heart rhythm that's too slow can cause insufficient blood flow to the brain with symptoms such as:

  • Fatigue or feeling tired or weak
  • Dizziness or lightheadedness
  • Confusion 
  • Fainting or near-fainting spells
  • Some people may feel short of breathe
  • Feeling like it's hard to exercise
  • In extreme cases, cardiac arrest may occur.

Complications of bradycardia

Severe, prolonged untreated bradycardia can cause:

  • Heart failure
  • Syncope (loss of consciousness; fainting)
  • Angina pectoris (chest pain)
  • Low blood pressure or hypotension
  • High blood pressure or hypertension

Treatment of the underlying medical cause

  • Not usually needed except with prolonged or repeated symptoms
  • Can usually be corrected with an artificial pacemaker to speed up the heart rhythm as needed
  • Some medications can cause a slow heartbeat, in this case, medication may be adjusted.

This content was last reviewed September 2016.


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