Mio Alpha First Impressions: Strapless Heart Rate Monitoring Comes of Age

There are a million reasons to want to know your heart rate while working out. Maybe you're trying to stay in a certain range for fat-loss. Maybe you want metrics on how you're progressing. Maybe you just need to make sure your heart isn't about to explode.

Figuring out your heart rate while running has always meant either wearing a stupid plastic chest strap or slowing way down and putting your fingers over a sensor on your watch. Both are inconvenient enough that most people don't even bother. The Mio Alpha watch aims to change that.

The Mio Alpha was a Kickstarter project turned real product. It's a watch that claims to measure your pulse as you run at speeds up to 12MPH, with precise accuracy, without the use of a chest strap. Just throw on the watch, set it to exercise mode, and go. On the back of the watch two green lights shine into your wrist, and an optical sensor can detect the subtle changes in the color of you skin that happen each time your heart beats. It's the same way medical oximeters work in hospitals, and it's a very accurate method.

The first thing you notice wearing the Mio Alpha is that the watchband is pretty thick, but there's a good reason for that—you have to cinch it down pretty snugly, and if the band were thinner it would cut into you. You have to wear it one to two notches tighter than you would wear a normal watch, especially if you're running, which isn't the most comfortable, but it's not enough to make your fingers go numb or anything. The watch itself just has two big buttons. You use them to set your target zone (high and low), switch exercise mode on/off, and start/stop the timer. Afterward you can scroll through a few stats from your last run. The watch has ANT+ and/or Bluetooth 4.0 Smart radios (for now you have to choose one or the other), which means they should interface with cycling computers and smartphones alike. More on that in a second.

It's a dark display with light numbers. That makes it pretty easy to read in bright daylight, but if it's dim, you aren't going to be able to see anything. Once you flip the watch into exercise mode it takes about ten seconds to lock in, and then you're good to go. You hit the start button to initiate the stopwatch, and then you're on the clock, with the watch monitoring where you are in relation to your target zone. If you're below it, a blue LED glows. If you're above it, a red LED glows. Get the green LED and you're Goldilocks. It's very intuitive.

The good and most important news: it reads your heart rate really well. I found it to be at least as accurate as any (infernal) chest strap I've used. I checked it against two other methods, and the results bore out. It did lose my pulse twice when I was on a 20 minute run with intervals. The first time was because the watch wasn't quite tight enough. The reason it happened the second time is a mystery. The watch is water-resistant enough to swim in, so I kept in on for my post run shower. Again, it lost connection briefly, but otherwise seemed to do fine. I'll be pool-testing it this week.

Now let's talk about the negatives. First, I had major issues with connectivity. The MIO Alpha uses the Bluetooth 4.0 Smart protocol. That means it should work with the fitness apps on your Bluetooth 4.0 enabled phone (iPhone 4S, iPhone 5, Galaxy S III, Droid DNA, Droid RAXR HD MAXX, etc). It doesn't. Not yet, anyway. I tested it with four devices (three Android phones and the iPad Mini). The Android phones could see the Alpha, but couldn't pair with it. The iPad couldn't even see it. But, then Nordic made a little app for the Galaxy S III called nRF Utility, and that could read the heart rate coming through in realtime, no problem. This leads me to believe that it's more a question of developers needing to update their apps for compatibility, but we shall see.

The other downside is that the watch just feels a little too bare bones. Yes, it reads your heart rate and all, but it can't even do split times in the stopwatch! Considering that's been a function on cheap Casio watches for several decades now, that (and the lack of a countdown timer) seems like real miss.

The Alpha comes with a little USB charger. It claims the battery will last 8-10 hours in exercise mode (and much longer when it's off), and so far so good on that front. Unfortunately there is no light on the screen, so if it's dark, you can look at the colors of the LEDs and know whether you're over or under your target zone, but you can't tell what time it is.

The Mio Alpha has been fine so far, but the Basis B1 band is about to launch. Not only does the latter have the same pulse-sensing technology, but it has four other sensors for testing how much you're sweating, how well you're sleeping, and other metrics. It claims to last four days while continuously monitoring 24/7. All of that blows the MIO Alpha away on paper, but it's how they perform that counts. They both cost $200, and we can't wait to see how they measure up when put head-to-head.

In the meantime, we're going to keep testing the MIO Alpha and see how things evolve. Hopefully all of our favorite exercise apps will support it soon, and then we'll get a better idea of what it's capable of. [MIO]