3 reasons fitness buffs may want a Mio SLICE

If reaching 10,000 steps every day isn't helping your meet your health goals, consider Mio's new wristband tracker SLICE. By focusing on only one metric — a score tied to your heart rate — it could be the game-changer you need.

mio slice four colors
Mio Global

I know it’s absurd. But it looks like I’ll be using three activity trackers every day from now on. And when you read about Mio’s SLICE ($129), you may want to get one, too. 

Why I still wear Fitbit and an Apple Watch

I’ve worn a Fitbit since fall 2012. That’s almost five years of activity data I want to continue building. Plus, I wouldn’t want to drop off the Fitbit leaderboard, where I compete with a dozen friends and family members. And Fitbit Charge 2 ($150) is, in my opinion, the overall best activity tracker, period.

When the Apple Watch came along in April 2015, I couldn’t resist. I love my Apple Watch Nike+ edition ($369 and up) for all the things it does, including fitness tracking and, yes, the ability to share activity data and compete with others.

So I wear a Fitbit next to my Apple Watch, or in my pocket. And that should be more than enough activity tracking for one person.

But last week, I started testing Mio SLICE. And unlike 99 percent of fitness devices I test, I plan to keep wearing it, at least for the foreseeable future. Here are three reasons why.

1. I’m working out harder

Apple Watch and several Fitbits offer heart-rate tracking, as do many other wearables. It’s one metric among several that you can track, when working out, at work, or sleeping (at least with Fitbit).

Some activity trackers put more emphasis on heart rate. For example, Moov Sweat HR ($100) and Moov HR Burn ($60) use your heart rate to provide real-time fitness coaching during high intensity interval training.

But Mio SLICE is the first wearable I’ve tested that’s all about your heart rate, all the time, thanks to its Personal Activity Intelligence. PAI is an algorithm that assigns a number to the intensity of your activity. Your goal is to achieve a PAI score of 100 or more over a seven-day period, for optimal fitness.

How do you earn those points? By engaging in activity that elevates your heart rate into your moderate or high range.

Let’s say you go for a leisurely 90-minute walk with a friend. On this walk, you’ll probably meet or exceed your daily 10,000 step goal. But because you likely didn’t raise your heart rate much, your walk won’t noticeably affect your PAI score. In fact, I took such a walk and only earned 3 PAI points — and that was because I interjected a few sprints into the stroll.

Now, imagine that you go for a run, take a spinning class, work out on the elliptical or swim.

(Quick aside: SLICE is rated at 3 ATM, which means it's "water resistant" but not approved for swimming. However, a Mio spokesperson assured me that in recent tests, SLICE met the higher 5 ATM standard. "You can swim with SLICE and Mio will replace the device if something happens," the spokesperson told me.)

With any of these activities (and others), you’re likely to raise your heart rate consistently. And as a result, up goes your PAI score. Example: For a 60-minute, moderately paced workout on a treadmill followed by an elliptical machine, I earned 30 PAI points.

Bottom line: I’m pushing myself harder in my workouts, and it’s because of PAI.

pai app images Mio Global

2. It’s not complicated

The simplicity of the PAI approach is refreshing. You’re focused on only one metric, your PAI score. And yet, you have many ways to achieve your goal. Plus, you have seven days to reach the target. 

3. It’s flexible

If you’re stuck in meetings all day Monday, you probably won’t make your 10,000-step goal. That can be discouraging. However, with PAI, if you miss a workout one day, you can work a little harder the next. Again, you have seven days to hit your goal, instead of trying to meet a daily target. That alone could be more motivating over time for some people.

Health research supports this strategy, by the way. The Department of Health and Human Services recommends that healthy adults get at least 150 minutes of moderate aerobic activity, or 75 minutes of vigorous activity, every week, or some combination thereof.

Worth mentioning: PAI itself is based on scientific research conducted by The Norwegian University of Science and Technology, which was reported by The American Journal of Medicine.

And now, the disappointments

* You can't read the screen outside when it's sunny. PAI’s OLED screen is nearly impossible to read outdoors on a sunny day, even with brightness turned all the way up. The company spokesperson told me Mio is aware of the problem and is looking to improve it in a future generation product. For what it's worth, most OLED activity tracker screens are hard to read outside. But SLICE is among the hardest to read.

* Battery life is subpar. Battery life is up to five days, according to Mio. But I had to recharge SLICE every two or three days, even with screen brightness at the recommended ‘medium’ level and notifications (phone calls, text messages, and calendar alerts) turned off. "Mio is working on releasing a firmware update after doing a round of battery optimizations," the spokesperson said. "There is room for improvement and we are confident we can get it to 4-5 days."

* No leaderboard. There’s no social leaderboard, on which you can compete against others to see who reaches his/her PAI score the fastest. Mio has plans to add social components to its mobile app, the company said. 

* More details, please. And while the app is easy to use and streamlined, more detail would be welcome. For example, the PAI app provides your resting heart rate, based on your most recent sleep tracking data. But it doesn’t let you see how your resting heart rate has changed over time. Tracking the history and trends for resting heart rate, slee, and PAI scores is also on Mio's roadmap, according to the company.

* Step counts are low. Step counting is a secondary function for SLICE, and it shows, as it consistently underreported my daily steps, compared to Fitbit and Apple Watch.

SLICE could still be a game-changer

These are disappointments, not deal-killers. And I still maintain that Fitbit Charge 2 is the best activity tracker for most people. It simply offers lots more useful features than Mio SLICE.

But if you want to laser-focus your exercise on heart rate — and honestly, isn’t the heart your body’s most important muscle? — seriously consider Mio SLICE, currently the only product built around PAI. It could be the game-changer you're looking for.

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