---
title: "How do fitness trackers measure heart rate?"  
description: "How do fitness trackers measure heart rate?"  
author: "Baishakhi Ghosh"  
published: 2023-11-16  
updated: 2023-11-17  
canonical: https://answers.mindstick.com/qa/108047/how-do-fitness-trackers-measure-heart-rate  
category: "technology"  
tags: ["technology & healthcare"]  
reading_time: 1 minute  

---

# How do fitness trackers measure heart rate?



## Answers

### Answer by Saumya Mishra

**Light [sensors](https://www.mindstick.com/news/2135/to-remotely-eavesdrop-on-phone-calls-scientists-employ-sensors) are used by** [**fitness trackers**](https://www.mindstick.com/blog/299632/major-benefits-of-using-a-smartwatch) **to determine a person’s** [**heart rate**](https://www.mindstick.com/blog/300232/how-do-i-check-my-pulse)**.** These are just a couple of examples in addition to others such as sensors that shine light through the skin to help reveal the amount of blood flowing in your body to determine how many times your heart beats per minute.

- The **PPG [technology](https://www.mindstick.com/articles/43990/4-reasons-why-startups-should-invest-in-good-technology)** is used by the light sensors. **PPG** is one of the non-intrusive methods for measuring clinical data.
- They utilize [green](https://www.mindstick.com/articles/95829/think-green-sustainable-design-considerations-for-commercial-buildings) light since red blood absorbs it pretty well. This allows accurate reading from the optical [sensor](https://www.mindstick.com/news/1912/with-the-use-of-sweat-sensor-could-track-medication-intake-within-30-seconds) on the amount of blood flowing through, as well as heart-beat counts.
- Each of these trackers has a[**LED**](https://www.mindstick.com/articles/43797/reasons-why-led-lights-can-be-a-lifesaver)that sends a green beam towards the skin in your wrist. At the rear of the tracker there is an optical sensor that senses the reflected light.
- The [accuracy](https://www.mindstick.com/blog/301099/how-accurate-are-pulse-oximeter) in [wearable](https://www.mindstick.com/articles/23525/new-tech-in-the-construction-industry) [devices](https://www.mindstick.com/news/2581/android-and-google-nest-devices-can-now-communicate-with-matter) is about **20%** when it comes to heart rate measurements.


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Original Source: https://answers.mindstick.com/qa/108047/how-do-fitness-trackers-measure-heart-rate

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