Most Popular Questions About Mio SLICE

Whether you own a SLICE, or just learning about how activity trackers like SLICE can motivate you to get fit and stay healthy, it's always good to review the FAQs. So we've included our most popular topics below. Use them to get better accustomed to Mio SLICE and learn about our tracking metric—Personal Activity Intelligence (PAI).

Why is SLICE more effective than other activity trackers?

SLICE is the first device to feature PAI, a scientifically-validated algorithm that translates your heart rate into a single, personal score, showing you how much activity you need to stay healthy. PAI was discovered during the Hunt Study, one of the largest health studies ever performed involving 45,000 people over 25 years. It was determined that maintaining a PAI score at or above 100 for a rolling 7 days gives you maximum protection from cardiovascular disease.*

Since PAI is calculated over a rolling 7-day period, you can be more active on some days, and less on others.

You can choose any activity that increases your heart rate—even those that don't involve steps. The more intense your activity, the more PAI points you'll earn.

What are PAI points?

Your PAI score is based on your heart rate data and your personal profile, including age, gender, and fitness level. PAI's algorithm is based on data collected from the HUNT Health Study over a 25-year period involving 45,000 participants conducted by the Faculty of Medicine at the Norwegian University of Science and Technology and developed by Professor Ulrik Wisløff, one of the world’s leading scientists in Exercise in Medicine. From this study, we were able to prove that you can live a longer, healthier life by maintaining a PAI score of 100 over a 7-day rolling window.

How is PAI calculated?

PAI is a measurement that gives you the health effect of each activity. It's calculated using your heart rate data and your personal profile. After your first week of earning PAI, you will start to notice how the rolling 7-day window works. For each day that passes, you replace one day's score with another day's score.

For example, after 8 days, you will gain the PAI you earned on the 8th day, but will lose the PAI you earned on the 1st day...on day 9, you will gain the PAI you earned on the 9th day, but lose the PAI you earned on the 2nd day... and so on.

This method of replacing one day of PAI with another ensures your score is accurate across a rolling 7 days.

In summary, the PAI algorithm re-calculates your PAI score each day throughout the week

Why is PAI a more accurate reflection of fitness than other metrics?

Goals such as '10,000 steps per day’ or ’30-minutes of activity per day’ tend to be vague and misleading. PAI analyzes your heart rate and provides a single measure indicating whether or not you are getting enough exercise. You can choose any activity that gets your heart rate up, no matter how many steps you take.

How often does SLICE measure heart rate?

Your heart rate is monitored 24/7 when your SLICE device is on your wrist. During times of inactivity—such as periods of sleep or low intensity—heart rate sampling occurs between every one minute and five minutes to conserve battery since you won’t be earning any PAI points during that period. As your heart rate increases—such as periods of moderate and high intensity—SLICE captures your heart rate every second, continuously.

Below are SLICE’s four heart rate sampling rates:

SLICE has four heart rate sampling rates:

  • Rest: SLICE captures your heart rate every five minutes.

  • Low Intensity: SLICE captures your heart rate every minute

  • Moderate to High Intensity: SLICE captures your heart rate every second, continuously

  • Sleep: SLICE analyzes your sleep, captures your heart rate every five minutes, and measures your resting heart rate.

Can I use SLICE with other fitness apps?

SLICE can stream your heart rate to any fitness apps that support Bluetooth heart rate streaming. To get started, put your SLICE into Workout Mode and keep your phone nearby to stay connected. A few apps that support streaming with SLICE include MapMyRun, Strava, PEAR Training, and more.

How do I know if I have the latest FIRMWARE?

You can check your firmware version in the Mio PAI app settings screen when you tap on the SLICE.

Click for Android and iOS firmware update instructions.

Firmware update troubleshooting


If you'd like to browse through the rest of our FAQs, you can visit our Support page. You can also contact our customer support team any time at

*To learn the science behind PAI, visit

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