Bradycardia | Slow Heart Rate

Updated:Jan 5,2017

Bradycardia = too slow

View an animation of bradycardia A heart 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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