
Key Takeaways
- Sinus tachycardia is a heartbeat coming from the normal command center (sinus node) at a rate greater than 100 beats per minute.
- It is normal to experience sinus tachycardia due to physiological triggers like exercise or stress.
- If you experience elevated heart rates without any causes or triggers, it is best to see your health care provider immediately.
You've likely noticed your smartwatch ECG showing a high heart rate reading when you're running, doing a HIIT workout, or stressed. You've probably experienced sinus tachycardia, and it is quite normal. However, if your heart rate has shot up beyond 100 beats per minute (BPM) and you haven't moved an inch, you could have developed inappropriate sinus tachycardia, and it may be time to check your heart health.
Here is everything you should know about sinus tachycardia.

What's Sinus Tachycardia?
Sinus tachycardia is a heartbeat coming from the normal command center (sinus node) at a rate greater than 100 beats per minute.
A normal functioning sinus node modulates your heart's rhythm and speed. Your heart's normal regulated rate and rhythm should fall within 60-100 BPM. Anything more than 100 BPM indicates sinus tachycardia.
The cause of sinus tachycardia differs from person to person for various triggers. However, your underlying trigger will most likely determine the outcome. According to the American Heart Association, there are two types of sinus tachycardia, normal and inappropriate.


Normal Sinus Tachycardia
It is called normal sinus tachycardia when the cause of elevated heart rate is known. These physiological elevated heart rates respond to certain triggers like fever, pain, exercise, or stress.
Other triggers are induced because of stimulants like caffeine and abrupt stopping of alcohol consumption. However, most of the triggers of normal sinus tachycardia are associated with our lifestyle and everyday activities.
Inappropriate Sinus Tachycardia
When your elevated heart rates are recorded, and the causes or triggers are not identified, this is diagnosed as inappropriate sinus tachycardia (IST). Increased heart rate of an individual with IST occurs even when at rest.
IST could sometimes be misdiagnosed as depression. The triggers for sinus tachycardia can be physiological or pathological. Everyday life activities cause physiological triggers, including pain, anxiety, exercise, and stress. Whereas pathological triggers are caused by both cardiac and non-cardiac causes.
Cardiac pathologic causes include:
- Supraventricular tachycardia
- Ventricular tachycardia
- Polymorphic ventricular tachycardia
- Myocarditis
- Cardiac tamponade
- Acute coronary syndrome
Non-cardiac pathologic causes include:
- Respiratory: Pulmonary Embolism and Hypoxia
- Gastrointestinal: Hypoglycemia, Dehydration, and Hyperkalemia
- Infectious Disease: Sepsis
- Hematologic: Hemorrhage and Anemia
- Toxicology: Medications like Albuterol, Anticholinergics, and Antihistamine
Any Cause for Concern?
Sinus tachycardia is a normal occurrence in human beings due to everyday activities and life burdens. Doctors view sinus tachycardia as a physiological response to activities and emotions like exercise and stress. Therefore, you should only be worried if sinus tachycardia occurs when you're at rest or if it is pathological.
Those showing signs of potential unexplained sinus tachycardia during rest and without emotional stress should immediately see their health care provider. The doctor will assist with identifying the underlying issues which may have triggered tachycardia.
Common Symptoms of Sinus Tachycardia
Sinus tachycardia is usually asymptomatic. However, below are the common signs and symptoms to look out for:
- Difficulty exercising
- Change in blood pressure
- Difficulty in breathing
- Chest pain
- Dizziness
- Fainting
- Headache
- Anxiousness
If you experience any of these symptoms, you should immediately call a doctor or 911.
Still Not Sure How to Spot Sinus Tachycardia on Your Watch ECG?
Smartwatches are proving to be a reliable monitoring asset for sinus tachycardia and other heart rhythm abnormalities. Our innovative QALY app can analyze your smartwatch ECG, provide detailed analysis from a cardiac technician, and help you monitor your heart health with ease. So if you need to keep a close watch on your heart health and have an ECG-enabled smartwatch, please contact us today for more information.
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