The Bio 2 will track steps taken, heart rate, distance traveled, calories burned, active minutes, and sleep.
Steps are tracked using internal hardware to detect movement, and this movement is then determined to be a step (or not a step) based on a unique step tracking algorithm.
Heart rate is measured using the green LED light and a light‑sensitive photodiode on the underside of your Bio 2. The light flashes on the blood pulsing under your skin and the photodiode measures the amount of green light absorbed. The amount of light absorbed at a given time determines your heart rate. (And it's also why you need good skin contact with your Bio 2 and to be reasonably still to get accurate heart rate readings.)
Distance traveled is calculated using 3 factors: number of steps taken, speed of those steps, and set stride length. Stride length can be adjusted under user settings in the Striiv app menu.
Calories are calculated using 4 factors: set weight and gender visible in user settings, the number of steps recorded, and the speed of those steps.
Active minutes are calculated for any activity lasting 5 seconds or more. Any movement lasting less than 5 seconds will not count towards an active minute.
Sleep is tracked using the same hardware used to track movement of the Bio 2. Asleep, restless and awake periods are based on intensity of movement ranging from no movement, very little movement and recorded steps (corresponds directly with asleep, restless and awake measurements).
To view previously recorded data for all of these activities, simply select the tile for the desired activity on the Striiv app home screen. Here you'll see a graph appear showing previous data. For more information on how to navigate these graphs, reference the following article.