Mio is the original optical heart rate monitor device manufacturer in the sports environment; launching their first device, the Mio Alpha on Kickstarter in 2012, since then Mio has expanded to an array of other wearables. Not resting on their laurels though, Mio have revisited their original device, and updated it as the Mio Alpha2 – reviewed here
For the original Kickstarter, the Mio Alpha was offered with both ANT+ and Bluetooth.
Personally I think this is a real shame that this was not offered further on a final release version.
The reason being in the Mio Alpha2, the optical HR works, and very well too. The Mio Alpha strap, and curve of the device is one of the reasons for this. As I have said before in the Epson Sf-810 review, light is the enemy of optical heart rate monitors, as its the light being reflected back from your capillaries that the monitor is recording.
But we’ll come to a little more of that shortly, lets look at the actual device first
I REALLY like the design of the Mio Alpha2. Some sports watches are a little subdued, or just a little too utilitarian.
I really like the yellow and black, on the review model. It is not a watch to really wear with a suit, but that doesn’t matter, the Mio Alpha is unashamedly a sports watch, and the design is all the better for it.
With this in mind, I think the Mio Alpha 2 actually looks better on the wrist, as it’s not trying to compete in multiple environments
Staying with the hardware of a bit, the Mio Alpha strap, is frankly one of the best straps I’ve ever used, its broad, surprisingly soft touch, ever-so slightly elastic, but at the same time seeming to be quite strong. The point here being it allows the watch to press down onto your skin, stopping the watch moving about, and preventing stray light getting to the sensor. As it strap is perfectly designed from an elasticity point of view, its holds the watch close to your skin but never feels tight. Overall its a really comfortable watch strap to put on.
Given the effectiveness of the strap, and how well the sensor works, the inclusion of ANT+ broadcast on the device, would basically have made my chest heart rate monitor redundant when on the bike. What makes this even more odd, is that Mio produce a series of screen-less optical HR wrist bands, the Velo and the Link which have ANT+ functionality, AND bluetooth!
I think if they had combined ANT+ and Bluetooth in the Alpha2, as a watch, it would have made a difficult choice to turn down, for many athletes
As it stands, the Mio Alpha2 can only transmit over bluetooth, which is fine if you are riding with Strava on your phone, but regrettably means the chest strap still has to stay for many cycling head units – especially Garmin head units.
Speaking of Garmin, they now use the Mio sensor under license, in their new ForeRunner 225
I’ve noticed that of late many of the manufactures have been using proprietary charging connections. Which I do consider a negative. If only because it can result in some relatively bulky chargers, and also means you can’t afford to loose the charger.
Mio have produced probably the most travel friendly charger I’ve seen to date
The charger has a small magnet inside, so when you line up the contact points, there is a reassuring *thunk* as the charger pulls to the watch
Optical Heart Rate Monitor
How does this black magic actually work?
The science is simple to explain, but the fiendishly difficult part, and the bit that makes Mio, well work, can be brushed off with “its done with advanced electronic circuits”. But lets have a quite look at the theory anyway
So here goes:
The Mio pulse sensor produces a green light. This light is able to penetrate the skin, and will reflect off the blood capillaries in the surface of the skin.
Every beat of the heart, this is transmitted through the volume of blood, which is why you can feel your pulse at the wrist. Similarly the volume of blood in the capillaries will also pulse.
These pulses, change the volume of blood in the capillaries, which makes the green light reflect slightly differently. This difference between reflected light is detected by the sensor, the difference measured and the heart rate calculated.
Seems simple enough. Heck I’ve had an optical pulse reader in by doctors bag for years…BUT its a real pain in the neck to use, especially on children…as they move.
Suddenly the whole idea seems a little bit more complicated – they want to measure small movements of fluid, under the skin. Skin which will be sweaty, and moving when you go for a run… OKAY
Mio was able to overcome this with a separate motion detector in the sensor, so that the watch can separate your movement, from the movement of your blood – in exactly the same way as an optical stabilisation in your digital camera works. Suddenly the sensor is “stabilised” and it can read the pulse again!
However the optical sensor can’t compensate for stray light, hence the watch has to be firmly attached to the arm.
Similarly, you have to wear it a little higher up your arm, away from the bones of your wrist, to give it a better surface to work on.
The fit on the wrist is a little high as a result, but you quickly get used to that
- On board memory for 25hrs of activities without your phone
- Internal accelerometer for: pace, speed, calories and distance
- Tap the screen for back light
- Timer functions – Countdown, chronograph and repeat timers
- Bluetooth 4.0 smart connectivity
- Water resistant to 30m
- No GPS
- No ANT
The watch is a little hard to use from a button perspective, but functions very well with the phone app
First you set up your device, putting in your maximum HR etc. You can also set the Alpha2, to flash its status LED different colours to given an idea as to what range HR you are in. Useful for training, or if you have the timer or other field displayed on the watch
Syncing with the phone will down load any stored work outs, which you can then view
Its only a subtle thing, but I do quite like to colour coordination with the heart zones on the work out graph
Using the Mio Alpha2
To start a workout session, you press and hold the RIGHT side button. As you do so, the unit will switch on the sensor and green LED’s to begin looking for your heart rate – over 15-20 sec
The next change to the watch will be it finds, and displays you HR. Flashing the LED underneath the appropriate colour to indicate your zone
I found the output from the Mio Alpha to be comparable to that of my chest strap for both running and cycling. Its a real shame that there is no ANT+ reading, as personally I found the Mio much more comfortable that a HR strap, and much easier to take off!
Indoors, I found the sensor worked straight off -seen here using Zwift
However, like the Epson Runsense – which uses an in house optical HR – both would often give odd and erroneous HR readings, mainly too low, or not found, at the start of cold runs outside. Simply due to lack of blood flow to the skin.
Currently I’m not sure how they could over come this, and is certainly a factor to be aware of with all optic HR sensors currently
The Mio Alpha2 looks cool. Not that thats the be all and end all, what matters is how the device functions. But Mio do deserve serious kudos for the design, and particularly the strap. I wish my other watches were this comfortable.
BUT… and there are always a few buts. The watch feels a little limited, the inclusion of ANT+ broadcast would have made this a defining optical heart rate watch from my perspective. Limiting the Mio Alpha2 only the bluetooth seems an odd choice, but perhaps the choice was made to keep the costs down, coming at £50 below the RRP of the FitBit Surge
The accelerometer works well for pace, speed and distance when using the watch for running. But I have grown used to GPS inclusion on many watches, but then the pricing is very keen for an optical HR device.
Personally I like it a lot for gym and treadmill work. The lack of ANT+ does limit its value for me. The one big problem I have with the Mio Alpha2 is Mio produce a more focused product Mio Link/Velo, which give you ANT+ and bluetooth. You loose the screen, but Mio have a great iOS app, so I’m not concerned about that. I’d still be able to ditch my chest HR monitor for cycling, and save a bit of money too.
Based on the construction, design and that lovely strap. If I need another HR strap, I’ll buy a Mio Link/Velo. If I was just a casual running, using my phone for music and GPS, then the Mio Alpha2 is a well priced device to help you understand more about your own HR zones, and improve your running