Mio LINK Heart Rate Monitor Wrist Band

I am excited about not wearing a chest strap. I'm a thin person, and chest straps are frequently around my waist. This is to the point that I have stopped using HR measurement. For cycling, no big deal--power meter. For running, I'd like to have some metrics. Still, I cannot imagine wearing a chest strap during a marathon or ultra event.I purchased the device and put it on. Paired flawlessly with my 910XT Garmin using ANT+.The manual: I'm frustrated by the childish descriptions about where to position it: "above your wristbone." Okay, but what's a wrist bone? Are they talking about the ulnar styloid process or distal radius? Does "above" mean proximal or distal? Does moving it "up" mean moving it toward your elbow or your hand. Ventral/volar or dorsal? (Maybe some better diagrams.) How about an honest discussion of what makes it work better? Is it better in fat or skinny people? Is it better in light-skinned or dark skinned people? Hairy people? Should I shave my wrist/forearm (I might just to see if it helps). Reading various reviews, it's hard to imagine that the heterogeneous responses aren't at least somewhat related to people's physiologic, body habitus or other differing characteristics.Fit: I wear a Garmin 910XT on my left wrist (not exactly small device). I wear a RoadID on my right wrist. Neither is optional. A visit to the very sparse Mio website suggests I wear the strap about 2-3 cm proximal to my ulnar styloid process on the dorsum of the same wrist as my Garmin. This does seem to work better than at any other location. It creates a very tight fit and results in great communication across the 1 cm of air between the two. It's still not perfect. From reviews, it would appear that the most discouraged people are the more elite athletes, who have tried other products. More recreational athletes--people using "map my walk" on a phone--are more satisfied. Could this be because elite athletes are more able to gauge their HR by feel/exertional effort? Maybe more experienced athletes use ANT+ instead of BT? Maybe chubbier wrists block light intrusion better?Accuracy: Haven't done a head-to-head with a strap. I will and may report back. It has a significant lag, as others have noted, but for endurance running this is probably not a big deal. I have not seen my HR go above 160, even at a 6 minute/mile pace, which I simply do not believe. I am still fine-tuning the fit, and I will double check it with a Garmin ANT+ strap, used simultaneously with the Mio on a BT link. If I cannot measure high intensity levels, then the device is fairly useless, and I will return it. If it is not stable during hard trail runs, I probably will never use it.Software/Firmware: I am an Android user, and the app is very immature, almost embarrassing. I guess it does what it's supposed to. I would like to know if there is a future for device firmware updates, but there is no reference on the website. I suppose firmware updates could either be through the USB link or, more likely, Bluetooth from the mobile app. For comparison, the ANT+ firmware update utility from Garmin for its wireless devices (310XT, 910XT) is cumbersome and slow, presumably a limitation of its bandwidth.Wishlist:- More reliability and accuracy. This is the only important feature to me.- I wish you could somehow adjust sensitivity or smoothing. I would hope there would be updates to improve reliability and battery life.- Others have complained about the overburdened LED. I frankly only want it to tell me that it has a good contact with my skin and a link to my device. The latter is obvious when the readout says "--" on my Garmin 500 or 910XT, so really, I only want to know it's receiving a reasonable physiologic signal. I won't be squinting at the LED to tell if it's magenta or red, while trying to avoid cliff edges or passing cars. Simpler is better, and my heartrate straps have no on-device display characteristics.- Battery life. How about options to turn off BT or ANT+ if not using. Allow disabling the LED.- The straps are causing people trouble. Include both sizes. Sell replacements. Make a Garmin wrist strap replacement that encases the Mio Link against my "wrist bone." Team up with Road ID to make them compatible. We only have two wrists.====UPDATE 6/6/14Shaved my right distal forearm. Don't say I'm not trying to make this work. Ran a frequently used, somewhat hilly (102 m gain) 12 km (8 mile?) loop with the watch paired to 910XT. Pace was slow at 5:30/km or about 8:55/mi. Compared data using Strava and Training Peaks. My first 500 meters were wonky. My resting heart rate of 55 BPM was displayed for much of it, rising slowly to around 70-80, even though I could feel some exertion. By feel I was at 120-130 (I've had a HR monitor since 1991.) HR rose way too slowly. I adjusted the strap tighter and moved it so that it was abutting the watch, with the watch distal to my ulnar styloid. The strap is compliant, so it wasn't uncomfortable. After that, readings were believable, albeit lower than expected. Upon returning, I compared the same run from different days (Garmin premium strap), and the data were similar but a bit smoother. A hard uphill effort resulted in a peak of only 171 BPM, which seemed too low, but may be accurate based on historical data.I still have a 310XT, so my next project is to record a run simultaneously on both devices, paired separately to chest and wrist straps. I'll report back.One final thought: the battery life is rated at 500 charges, which is about 2 years. I doubt the wrist strap will tolerate this many duty cycles. I really hope that replacement straps become available in the future.UPDATE 6/9/2014I've now completed additional runs with the wristband in place. These include an 8 hour mountain run with various terrain, starting at close to freezing (3C) and finishing at body temperature (36C), ranging from 2000m to 3100m altitude. In the last week I've had the watch, I ran about 90km in it. I am satisfied that it is working correctly and can be very accurate--thankfully also precise--once I found the correct spot. The trick (for me) has been wearing it on the same arm as my Garmin GPS watch, wearing it proximal to the watch, approximately 1 cm away from the right sided buttons. I shaved my fairly un-hairy wrist in the area. It works well with or without UPF "arm coolers." over it.I have found that I can charge the module without taking it out of the wristband.I am changing my review from 3 to 4 stars. The Mio is not perfect. It's sill version 1.0, but it works. I will certainly purchase the next version when it becomes available and stable. I am reminded of my first Garmin Forerunner 101 wrist "watch" from 2003. It was huge, somewhat inaccurate, had a short battery life and was often a hassle, but ultimately it gave rise to some very good second, third, fourth and now fifth generation devices.UPDATE 07/19/2014The Mio Link has become as much a part of my running routine as my Garmin watch. I barely notice it now. The reliability has improved for me with time, probably as much my own learning curve as anything. Once in a while it goes haywire, either giving very high or very low numbers. In talking with Mio, there will be an eventual firmware update, but as of today there are no links to firmware versions or explanation of how this will eventually work. They acknowledged the problems that I experienced. The e-mail I got was receptive and seemed to be from a real person.

I really, desperately, wanted to like this product. It is a fantastic device when it works, but unfortunately, that's only when I am sitting around getting ready to go work out. Once I start working out however, different story :(.Scenario:1. Biking - I bought the link for this reason. It turns out however, that the HRM fails to register properly due to the bend of the wrists (while holding the handlebars). The manual suggests putting it higher on the arm, but it slips down once I start to sweat. I tried flipping the band so that the monitor is facing the inside of my wrist, and it definitely works better, but still fails to pick up my HRM continuously ~30% of my workouts.2. Running - forget about it. As soon as I start to sweat, the wristband slips down my arm. There is not much that can be done about this as the issue is 1) complicated by the swing of the arms while running and 2) even if the device is held tight against the higher part of my wrists, it becomes loose as soon as I sweat and it slips down.Lastly, and this probably what compelled me to return this, the LED color for when the device is not working is equal to the lower heart zone settings (i.e light blue), which more often than not, confuses the hell out of me. Even a small numerical LED would have helped to solve this problem.tldr - Great idea, poor execution. I now understand why Apple has yet to release an "iwatch"! The wrist a very tricky place to get accurate reads!

Now that I have used this heart rate monitor for a few weeks, I can say I wouldn't recommend it to others. You really need to try it in different orientations to get the best results. You also need to experiment with the tightness of the band. I've found that I get fewer spikes and drop-outs if I wear the strap with the sensor on the inside of my wrist, just above my GPS running watch (Forerunner 610). I think it is also important to allow the monitor acquire your heart rate and stabilize before you begin your exercise, it can sometimes show your heart rate as higher than actual, but it will stabilize lower if you wait a minute or two.Pros:-No chest strap necessary-Generally very accurate when worn right-Lots of adjustment in strap, strap comfortableCons:-Expensive-Battery life too short-Prone to incorrect readings if not worn right-Instructions are not very clear or specific about wear and troubleshooting-ANT+/BT4.0 signal strength very weakOverall, I really don't think this heart rate monitor is any better than a traditional chest worn heart rate monitor. The chest worn monitors are nearly aggravation free (when using an electrolyte gel) and don't require frequent charging. I've also never had serious transmission issues to my GPS watch from my chest worn strap like I have with this monitor. So, unless you just can't stand the chest worn heart rate monitors, this monitor just isn't worth paying the premium.