Fitbit Sense device showing 72 beats per minute heart rate and 63 beats resting heart rate

Heart rate tracking made for every day

In the past, heart rate tracking was expensive, awkward and uncomfortable. With the invention of PurePulse, we made it accessible to anyone. Inspired by a thimble-sized sensor used in hospitals, we conducted extensive research to make wrist-based heart rate tracking work in all types of environments.

back of Charge 4 trackers showing green lights in sensors

Photoplethysmography: a long word with a short explanation

We use light to measure blood flow. As your heart beats, the volume of blood in your wrist rises and falls. Blood absorbs light, so a sensor shines a light onto the skin while light detectors called photodiodes measure how much light is being absorbed. The rise and fall of the absorption signal represents each heartbeat. This tells you how many times your heart is beating per minute.

phone showing a linear trend for health metrics over time

Innovation backed by research

In a number of external studies worldwide, PurePulse technology has surpassed industry expectations. And over 50 patents related to PurePulse technology have been awarded to Fitbit’s heart rate innovation in the process.