I’m waiting for the bus outside this store that’s displaying fantastic workout clothes. I sigh and then turn my head to see a billboard about a new gym in town. I’m torn between guilt, for not exercising ever, and surprise at the shiny pennies people are apparently willing to shell out to get be fit and stylish. The bus comes by, I manage to squeeze into a seat, and then I open my magazine to a page where the article is titled “This Is the Compelling Science behind Fitness Trackers.” The universe is telling me something, isn’t it?
I’m inspired enough to pen this article where I’ll talk about different sensors that make activity trackers tick.
Mini labs juggling complex data—fitness trackers
It looks like a watch. It looks like a smartphone. It is so much more…
Then there is an Apple Watch vs. Fitbit Blaze debate going on.
Fitbit and Apple are two of the most popular fitness tracker manufacturers (Source)
This wearable is a wrist-based monitor with sensors that tell you if you’ve been walking enough, sleeping and eating enough, jogging or sprinting, staying out too long in the sun, and it tracks a whole lot of other stuff to keep you as healthy as you can be.
Research might scare you into buying one
Do you know what WHO says? Every year, 38 million people die from noncommunicable diseases globally and cardiovascular diseases account for the most. It’s a wonder we don’t wear an activity band on each hand.
Although you can’t peg heart rate monitors as indicators of potentially fatal diseases, ensuring that you’ve lowered your resting heart rate is a valuable wellness/fitness metric. (Source)
These words—obesity, diabetes, physical inactivity, smoking, alcohol, salt, blood pressure, cholesterol, and sleep patterns—figure largely in reports related to health and articles about the changing lifestyles of millennials. So, do we need these wearable digital monitors? Hell, yeah!
Unravelling the mystery of these tiny marvels
Some people think that the system complexity of fitness trackers is much lesser than a full-blown smart watch. But I disagree. A fitness tracker is some sort of a genius companion you ought to have.
Getting down to the details...
- Sensing layer: Collects data like footsteps, heart rate, temperature, etc., and sends it via GSM/GPRS/LTE.
- MAC Layer: Manages device control, quality-of-service, and power.
- Network layer: Handles transmission using IPV6.
- Processing and storage layer: Analyzes and stores sensor data with security control.
- Service layer: Delivers processed data to apps and services.
Now, let's take a close look at a few of these sensors...
Accelerometers
They measure acceleration forces to track motion, orientation, and direction—used in smartphones, rockets, and fitness bands.
Here’s a great video on how your iPhone knows up from down.
GPS
The GPS plays an important role in a fitness tracker (Source)
Used for location tracking via satellite signals and trilateration. Essential for route tracking and emergency alerts.
Galvanic Skin Response Sensor
Measures electrical conductance of the skin. Tracks emotion-based sweating, aiding stress and fitness insights.
Optical Heart Rate Monitor (OHRM)
Uses photoplethysmography to detect heart rate by shining light on skin and measuring changes in light absorption.
Bioimpedance Sensors
Measures resistance to current to determine heart rate, respiration, hydration, and more.
Temperature Sensors
Monitor body temperature for health insights. Crucial for athlete recovery and early detection of anomalies.
UV and Ambient Light Sensors
Help track sun exposure and adjust brightness/time metrics for user interface and circadian data.
Finding the right fitness tracker
Choose based on features—heart rate, sleep tracking, calorie counting, and more. Here are top options:
Garmin Vivosmart HR+ – Heart rate, sleep, steps, waterproof.
Fitbit Charge 2 – Tracks wellness, breathing, and activity.
Jawbone UP4 – Measures heart rate, breath, sweat via Bioimpedance.
Samsung Gear Fit2 – Built-in GPS, activity auto-detection.
Other good bands: Withings Go, Microsoft Band 2, Basis Peak, Moov Now, Misfit Ray.
While no sensor is perfect, fitness trackers are getting smarter and more accurate. Use them right and they’ll lead you to a healthier life.