How Does a Smartwatch Measure Your Heart Rate

In today’s world, there are new diseases in the human body and people often fall ill. In such a situation, it is very important for you to take good care of your health. In view of this need, many smartwatch companies have added many health features. The most popular of these features is heart rate tracking and it is also seen in almost all smartwatches. In today’s article, we will learn in detail about how does a smartwatch measure your heart rate and also try to know why we need heart rate.

What is Heart Rate? Why is it Important?

Heart rate is also known as pulse. Heart rate is the number of times a person’s heart beats in a minute. The heart pumps blood throughout the body, and this indicates the number of times it beats in a minute, as well as information about overall heart health.

What is Heart Rate

Heart rate can be measured from different parts of the body like neck, wrist, chest, pulse, foot, etc. The easiest and most common way to measure heart rate is by wrist.

The normal heart rate for an adult person is 60 to 100 beats per minute. However, this rate can vary depending on age, gender and physical activity level.

Apart from this, heart rate can also change depending on different conditions and activities. Like if you sleep then your heart rate decreases and if you exercise then your heart rate increases.

Must Read: What is SpO2 in Smartwatch? How does SpO2 Sensor Work in Smartwatch?

How Does a Smartwatch or Fitness Band Measures Heart Rate?

In the early days of smartwatches, we used to see the feature of heart rate sensor in premium smartwatches like Samsung Galaxy Watch Series, Apple Watch Series. But in today’s time, we get to see heart rate sensor in almost all smartwatches and fitness bands.

How Does a Smartwatch Measure Your Heart rate

Current smartwatches and fitness bands are using different technologies to measure heart rate, out of which two technologies optical sensors and electrocardiogram (ECG) sensors are most commonly used.

Optical Heart Rate Sensors: This sensor is present on the back side of smartwatches or fitness bands which is a small light-emitting diode (LED) and a light detector. This LED shines light into the skin and the light detector measures the amount of light coming back. The amount of light reflected back changes as it flows through blood vessels, which allows the sensor to measure heart rate.

Electrocardiogram (ECG) Sensors: Smartwatches and fitness bands that measure heart rate through ECG sensors measure the electrical activity of the heart. ECG sensors usually have two or more electrodes. These electrodes detect the electrical signals generated when the heart beats. By measuring these signals, the ECG sensor determines the heart rate.

How Accurate is Heart Rate Sensor on Smartwatches?

The heart rate accuracy of a smartwatch or fitness band depends on the technology used in it. Smartwatches with electrocardiogram (ECG) sensors provide more accurate heart rates than smartwatches with optical sensors.

How Accurate is Heart Rate Sensor on Smartwatches

Optical heart rate sensors use a small light-emitting diode (LED) and a light detector to measure heart rate. This sensor provides a light inside the skin, that light comes back after reflecting from the blood, which measures the heart rate. The data of this sensor can vary due to many factors like movement and skin pigmentation.

Talking about ECG sensors, they are more accurate than optical sensors but they are more expensive complex than optical sensors. It measures the electrical activity of the heart and allows for direct heart rate measurement.

Measure Accuracy of Heart Rate Sensor on a Smartwatch

The easiest way to check heart rate accuracy in smartwatches or fitness bands is by using pulse oximeter medical equipment.

To check the heart rate accuracy in a smartwatch, wear a pulse oximeter on your finger and wear your smartwatch or fitness band on your wrist. After this check whether the data on both of them is same or not. If the data is the same then the heart rate accuracy of your smartwatch is correct.

If you want to measure heart rate with accuracy, then you can use premium smartwatches like Samsung Galaxy Watch 5, Apple Watch, Fitbit Versa 2, etc.

Must Read: 5 Ways Smartwatches Are Improve Our Health (Updated 2023)

Should You Use Smartwatch or Fitness Band’s Heart Rate Monitor?

If you want to use the heart rate sensor of the smartwatch to get information about normal health or to measure exercise data, then you absolutely can.

But if you want to use it as a piece of medical equipment, then which doctor should you consult? Because heart rate can cause many serious issues which a smartwatch or fitness band cannot measure.

Some Popular Smartwatches with Heart rate Monitoring

Here are some popular smartwatches that supported heart rate tracking with 99% accuracy.

1. Fire-Boltt Supernova

  • 1.78″ touch display
  • Heart rate tracking
  • Blood oxygen level (SpO2) monitoring
  • Sleep monitoring
  • A calorie counter and step counter

2. Pebble Cosmos Luxe 2.0

  • 1.43″ touch display
  • Pedometer and step counter
  • Heart rate tracking
  • Sleep monitoring
  • Blood oxygen level monitoring

3. Google Pixel Watch

  • 1.2″ touch display
  • Heart rate tracking
  • Blood oxygen level monitoring
  • Blood pressure monitoring
  • 2 GB RAM and 32 GB Inbuilt

Frequently Asked Questions (F.A.Q.)

What Should be the Normal BPM?

The normal heart rate for an adult person is 60 to 100 beats per minute. However, this rate can vary depending on age, gender, and physical activity level.

What is a Dangerous Heart Rate for a Woman?

If the heart rate is consistently above 100 beats per minute, then it can be dangerous for a woman.

Wrapping Up

So friends, in today’s article, I have given you information about How Does a Smartwatch Measure Your Heart Rate and also about How Accurate is Heart Rate Sensor on Smartwatches. I hope you have liked this article. If you liked this article, then do tell by writing in the comment below.

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Hello friends, I am Tauseef Raza and I am the founder and content writer of this website ( If I talk about my education, I have done Master of Computer Application (MCA) which gave me a lot of interest in tech gadgets.

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