How Fitness Trackers Work: A Detailed Guide

How Fitness Trackers Work

A wearable fitness tracker is always tracking your movement. From your heart rate to the number of steps are being registered in your fitness tracker. Even some higher-end fitness trackers can tell you how much time you are connected to the ground and how effective your training is.

The question is, how do fitness trackers tell you these things? Also, how accurate these data are. So, today we will discuss the working principle of fitness tracker.

What Does a Fitness Tracker Do?

Fitness trackers keep track of various exercise and health-related activities. Most people are impartial to fitness trackers as they can count the number of steps they traveled. 

However, fitness trackers are more than step counting machines. These devices can inform you about your heart rates, tracks the quality of sleep you are having. It can even keep track of the menstrual cycle for females. 

Therefore, it’s evident that the fitness tracker tracks the vital health and wellness information of the user. It can encourage the user to achieve their fitness goal and get healthy. 

How do Fitness Trackers Work?

Fitness trackers host several sensors to track different vitality information. These sensors can vary from product to product. There are even fitness trackers for moms who push strollers. Here are some common and crucial sensors explained with the work they do.


The accelerometer measures movement based on changed direction and speed. Most fitness trackers host a 3-axis accelerometer for accurate calculation. This sensor measures the direction you move and helps in counting your steps.


The gyroscope is the sensor responsible for measuring orientation and rotation. A 3-axis gyroscope gives the fitness tracker 6 degrees of motion. This sensor assists the fitness tracker to account for complex workout motion.


The altimeter is used in the fitness trackers to measure altitude. This comes in handy when you are scaling mountains or climbing stairs.

Optical Heart Rate monitor

The optical heart rate monitor sensor is used for measuring heart rate. This sensor projects light on your skin to measure your pulse rate. By determining the pulse rate, it can measure the speed of the heart pumping blood. The higher the pulse, the faster the heart is beating. 


Global Positioning System (GPS) sensor is used for measuring and tracking distance. This sensor triangulates signals from GPS satellites and provides almost accurate distance data. 

Other Sensors

Among other featured sensors in fitness trackers bioimpedance sensors, temperature sensors are the most significant ones. Temperature sensors detect the hardness of a workout routine depending on the increased temperature of the body. Bioimpedance sensors collect heart rate data for more accuracy. 

How Fitness Trackers Utilize These Sensors?

The fitness trackers gather raw data from sensors present in them. Then these devices process these data and translate them for your convenience. 

How Fitness Trackers Count Steps?

The data from the accelerator and gyroscope are input in the fitness tracker’s personalized algorithm. The algorithm detects what the user is doing, from bench pressing to tree posing. 

Fitness trackers enable you to tell how many steps you have taken and at what speed. With some additional information provided, trackers can also indicate how many calories you have burnt.

How Fitness Trackers Monitor Your Sleep?

For tracking your sleeping pattern, you will need to set up your tracker into sleep mood. Therefore, the tracker will know that you are asleep and will track your movement through the gyroscope and accelerometer. 

With the data gathered by the abovementioned sensors, the algorithm will be able to tell the quality of your sleep. It can detect the different stages of your sleep cycle. Each stage of the sleep cycle has its own unique signatures. Your fitness tracker will also track your heart rate and incorporate the data for more accurate results.

How Fitness Trackers Measure Calories?

Measuring burnt calories with fitness trackers can come in very handy. However, burning calories vary a lot from person to person. Fitness trackers can give you an abstract idea of the calorie you have burnt but may not be spot-on accurate. 

When you have got a new fitness tracker, you will need to input certain information regarding your weight, height, gender, age, and some other relevant fields. With such information, the tracker’s algorithm is primed. After that, the fitness gathers data from the sensors and analyzes them with the algorithm.

Although the calorie count is not too accurate for light intensity workouts, it can provide almost accurate information for heavy workout routines.

How Fitness Trackers Measure the Height You Have Climbed?

For measuring elevation, fitness trackers feature an altimeter. When the user crosses ten feet vertically, the fitness tracker processes it as climbing up one floor.

The problem with tracking height is that it can fluctuate depending on various factors. Some altimeters use varying air pressure to measure elevation. Also, the fitness tracker can utilize GPS data and maps for the same reason. 

For altimeters, even the slight change of wind pressure can indicate that you have changed altitude while you have not. In the case of GPS and Maps, the fitness tracker may consider the river surface as the base and indicate you have scaled a lot while you are just standing on the bridge. 

However, more and more companies are now taking new approaches and combining sensors for more accurate results.

Final Words

For achieving fitness goals, fitness trackers can be very handy gadgets. Fitness trackers encourage and inspire their users to create a fitness routine and help in maintaining it. Your fitness journey can be recorded through a fitness tracker.

However, there are some measurements required to be calibrated more; overall, fitness trackers are reliable gadgets for indicating your health.

Fitness trackers are getting smarter and smarter and featuring new utilities for ultimate benefits. It is getting more personalized and providing information that can benefit your health and lifestyle. 

Also, a fitness tracker will remind you to walk when you have been sitting for a long time. Also, it will remind you to relax and drink water when you are too fatigued. Therefore, consider having a fitness tracker for the best benefits of your health.


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