How Do Smartwatches and Heart-Rate-Tracking Technology Work?


Smartwatches are popular these days because of how many vital statistics they can track. As such, they have become invaluable pieces of wearable tech, more so for fitness-minded individuals.

Among the most important health categories that smartwatches can track is a user’s heart rate. But how, exactly?

Here is a tech explainer.

Smartwatches ‘Look’ At The Skin for Signs

A few popular smartwatch makers, such as Apple, use a technology called photoplethysmography, or PPG for short. This is the same exact tech that Apple uses for its Apple Watch, writes MecHead.

The basic principle of PPG involves looking for traces of red or green light. It measures the amount of light that it can see when it “looks” at the skin of a wearer’s wrist, essentially.

As your heart pumps blood throughout your body, there’s an increased blood flow in your wrist. The increased blood flow means the absorption of green light increases.

Smartwatches like the Apple watch will also “look” for instances in between heart beats when there’s a decrease in the absorption of green light. That’s basically how wearable tech works. But of course, there’s far more to it than that.

Read also: Smartwatches Circadian Rhythm: Researchers Look for New Ways to Track Physiological Processes in Body

Basic Components of PPG Tech in Smartwatches

Watchranker enumerates the specific components that make PPG technology work. Here are the most basic parts:

  • Optical emitter: This component’s job is to send light waves into the skin of the wearer. It achieves that by using at least two LEDs. At times, some smartwatches will even use different LEDs that emit varying wavelengths of light, so it can compensate for the difference in a wearer’s skin tone and other physical attributes.
  • Digital signal process: All that light emitted by the LEDs must be captured after they’re refracted, then translated into ones and zeros (aka binary) to be “understood” and translated into heart rate data that you can see on the screens of smartwatches.

It’s also worth noting that the PPG technology found in smartwatches are also being used in other areas of healthcare. If you’ve ever seen a doctor or a nurse use an ear or finger clip that measures heart rate, that device is using PPG.

The Future of Smartwatches

Smartwatches and wearable tech in general have advanced so much over the years. According to ZDNet, manufacturers have been increasing the amount of the health-focused. Brinkwire Summary News.


Comments are closed.