Mio SLICE Visit Site

Pros / This is one of the few monitors in our review that is waterproof, so you can track your heart rate while swimming.

Cons / It struggles with accuracy – the device consistently reported lower heart rate data.

 Verdict / The Mio SLICE takes a unique approach to tracking your heart rate. If you need extra motivation, the SLICE and PAI app are a good combination.

The Mio SLICE is a unique heart rate monitor, as it tracks your overall performance on a day-to-day basis. The SLICE works with the Mio PAI app, which ranks your day based on your heart rate. You keep track of your daily fitness by earning slices of the PAI.

During testing, we found the SLICE was less accurate than other heart rate monitor watches. It also takes a while to populate your BPM on the screen. It consistently reported a lower BPM than our manually tracked heart rates as well as those tracked by other watches in our review. For example, if your heart rate is about 70 BPM, it’ll register as about 65 BPM. As with most of the top heart rate monitors we tested, accuracy diminishes the higher your heart rate is.

The real benefit of the Mio SLICE is that it’s a continuous, wrist-based monitor with a screen, so you can view your stats without opening the app. There’s a button below the display to navigate through screens such as PAI, BPM, steps, distance and calories burned. Some of our testers reported that the screen was nearly impossible to read in direct sunlight, so you might need to stop and cover it with your hand during daytime runs. The Mio SLICE is waterproof though, up to 3 meters underwater, so you’re free to wear it in the rain, in the ocean or during pool workouts.

There also isn’t an altimeter, so you can’t count flights of stairs. While you can track sleep, we found the SLICE tracked it even when we weren’t wearing the watch. It reported 11 hours of sleep, including periods of deep and restless sleep, when the SLICE was siting safely by itself in our test lab.

This Bluetooth heart rate monitor is crazy easy to sync – just opening the app transfers your data. You can see the battery level, your current BPM, previous workouts and the day’s data. The PAI app works like a slice of pie: Each day of the week is a slice that you must fill up with heart rate data and steps to complete the pie. While it’s a fun method of staying fit, it’s a bit confusing as to how much activity equals a PAI number, your hard data is viewable as an afterthought of the PAI number, and you can’t customize goals.

  • Heart Rate Accuracy
  • Weight
  • Waterproof
  1. Higher accuracy watches give you a better picture of your heart fitness.
    Higher is Better.
  2. 9  Mio SLICE
    82.6 %
  3. 95.7 %
  4. 94.4 %
  5. 92.0 %
  6. Category Average
    93.54 %


The SLICE has smartwatch notifications and vibrating alerts and is even compatible with other fitness apps. We recommend this wrist heart rate monitor if you’re not looking to track steps. Its real value is in the unusual PAI app, where you focus on your day-to-day PAI number instead of the minute details.

Mio SLICE Visit Site