Heart Education
5
MINUTE READ

Sinus Bradycardia: when is low heart rate a problem?

ReadMyECG Team
Sinus bradycardia is the medical term for a slower heart rate than expected.

Key Takeaways

  • Sinus bradycardia is when the heart rate is slower than 60 beats a minute.
  • It is usually a normal finding, especially in young athletes.
  • It can also be caused by medications such as beta-blockers or calcium channel blockers.

When your smartwatch tells you that you have a low heart rate reading, what does it mean? Your heart rate is then below 60 beats a minute, indicating bradycardia.

Here is everything you should know about sinus bradycardia

Sinus Bradycardia recorded by an Apple Watch ECG. Note the heart rate is below 60 BPM.

What Is Sinus Bradycardia?

Sinus bradycardia is the medical term for a slower heart rate than expected. The average heart rate in an adult ranges from 60 to 100. Sinus bradycardia is when the heart rate is slower than 60 beats a minute. The conduction system that stimulates heartbeats produces beats at a slower rate. However, that does not mean that everyone with a heart rate of 59 should be calling their doctor. Sinus bradycardia does not always cause symptoms. However, some people may experience symptoms such as lightheadedness, shortness of breath, fatigue, dizziness, and fainting.  

What are Common Symptoms of Sinus Bradycardia?

Most people are entirely untroubled by a slow heart rate and have no symptoms. For most, seeing sinus bradycardia on a heart tracing is the first indication they have a slow pulse. However, some people experience shortness of breath, dizziness, fainting, or even chest pain. Others feel tired and need to rest more after doing something. Confusion is another symptom of having a slow heart rate and is linked to insufficient blood circulating to the brain. 

Is Sinus Bradycardia a Cause for Concern?

The good news about sinus bradycardia is that a lot of the time, it is a normal finding, especially in young athletes. A resting heart rate of 40-60 during sleep is also normal in healthy people. However, sometimes sinus bradycardia can be caused by medication such as beta-blockers or calcium channel blockers. Some people feel okay with a slower heart rate, but others may need their medication adjusted. 

Other sinus bradycardia causes are the scarring of the sinus node in the heart as people get older. Electrolyte abnormalities can also cause sinus bradycardia, as can several underlying heart muscle and electrical disorders. A thyroid disorder is another reason for a slow heart rate. Some people get a slow heart rate due to sleep apnea, which needs to be investigated by a doctor. 

So when should you seek help or be concerned?  

Sinus bradycardia can signify that the heart is not pumping blood as fast as it should be, particularly if you have accompanying symptoms. If you have chest pain or sudden shortness of breath, you should speak to a doctor or call 911. Experiencing dizziness, lightheadedness, or fatigue should also be checked out as it can indicate needing to get your medication adjusted or that you require further investigations. If there is no apparent reason why your heart rate is slower than it should be, you should also get this checked out with your doctor, as sinus bradycardia can indicate other problems.

Can a Smartwatch Capture Sinus Bradycardia? 

Smartwatches with an ECG recorder like the Apple Watch, Samsung Watch, and Fitbit can detect sinus bradycardia and other cardiac arrhythmias. However, a smartwatch cannot record a full 12-lead ECG showing the different sides of the heart. Instead, you simply get a single lead tracing. Some smartwatches can also record the activity you were doing when your heart was breathing slower than normal, which can be helpful to a doctor when diagnosing problems. 

Staying Healthy Is Important

A smartwatch has many features to help you stay healthy. Take time to get to know your watch and use some other apps to learn how it works with calorie counting, healthy exercise, sleep patterns, and the heart monitoring feature. All these help you to have a healthy lifestyle and protect your heart. The more you use your smartwatch to do things, the more you will benefit from having one. 

Finally, if you are concerned about the ECG tracings from your smartwatch, you can get them reviewed by experts for arrhythmias within minutes. It will give you peace of mind and help you to get an assessment if needed. So reach out to us (Android or iOS) if you have any questions.

Get second opinions of your ECGs by human experts on the ReadMyECG app!

Download ReadMyECG app from app store
Download ReadMyECG on Google Play

Get second opinions of your ECGs by human experts on the ReadMyECG app!

Interpret My ECG Now

By using this website, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. View our Privacy Policy for more information.