The Scosche RHYTHM+ is a forearm or upper-arm worn heart rate monitor belt. It uses optical technology to read your heart rate and it is generally claimed to be the most accurate optical device on the market (July 2015 – March 2017).
It supports a single Bluetooth connection via Bluetooth Low Energy (BTLE/BLE, Bluetooth SMART, V4) AS WELL AS multiple ANT+ connections simultaneously.
Regular readers of my reviews will no doubt have spotted an unhealthy interest in heart rate monitors. Finding yet another place to wear one is super-exciting (well……)
Will it live up the hype?
Here’s the back of the box showing a PerformTek precision sensor is used. Actually it ultimately comes from Valencell…but that’s OK. They’re good. All you really need to know is that it can simultaneously connect to ONE Bluetooth SMART (low energy, V4) watch/smartphone AND as many ANT+ devices as you want.
Inside the box you get a few bits and bobs most notably the vendor-specific charging USB cradle. It would have been nice to work off a generic micro-USB cable but that’s not too important.
You don’t need the Scosche RHYTHM+ manual but here it is anyway as a link. You get one in the box telling you how to wear it and how to charge it but it really is pretty obvious. The actual sensor part is worn on the INSIDE of your arm.
You get two straps. A big one for your upper arm and a small one for your forearm – if you are a child then you could probably wear this. Interesting as very few HRMs will fit smaller children or, I suppose, smaller men/women. This one will probably fit just about anyone. I’ve got relatively small arms.
The strap is comfy to wear (I had expected the opposite) and attaches by Velcro. Velcro, by its nature, is a bit annoyingly sticky sometime but the Velcro kept the band securely on my upper arm. When worn on the recommended forearm position it felt as if it were about to move – I guess I could have tightened it up!
Pressing and holding the single button on the front of the device (where the ‘S’ logo is) turn it on or off and when on it can easily pair with your BTLE/ANT+ device.
Here’s the rear of the device showing the 3 sensing lights (2 colours) and 2 charging pin connectors.
Basic Operation and Background:
The device comes with sufficient charge for a first usage. After a full charge it will last over 7 hours. It will probably last longer on un-tattooed, white, hairless, not-very-sweaty people for a variety of technical reasons.
Optical HR devices are ‘the’ trend for 2015/2016 sporty-wearables. So we already have quite a few devices on the market. MIO (Philips) is probably the market leader but this may change as more entrants and technologies come to market. But MIO are in a great place with partnerships with Garmin and Adidas and TomTom as well as their own products. TomTom (Sept 2015) have just moved away from MIO and just because MIO are the leading product does not necessarily mean they are the best as we shall see.
The recommended wearing position is the inside of the forearm. But you could wear it on your wrist or upper arm. I’ve used the upper arm which works pretty much exactly the same as on the forearm for me. It may vary from person-to-person.
I’ve spoken to Valencell about the positioning and colour of the LEDs. Two colours are used for better readings AND the lights are also spaced further apart for better readings. Compare to the MIO below:
Supported devices with ANT+and Bluetooth Smart:
Most new things will pair to this band: Polar, Suunto, smartphones of the iOS and Android varieties and Garmin. Potentially in ANT+ mode it will make the battery last even longer as ANT+ consumes less power – I didn’t test that.
I tried to pair it with many devices and they all worked. With a Polar M400 it took a little while to pair and the Schsche had to touch the M400 – but that was true of any HRM pairing with the M400.
The device will pretend to support HRV but the data will not be accurate. No optical devices yet supports HRV (September 2015) although later this year products that implement more frequent sampling rates may be able to deliver that.
I planned a large series of tests to push the Scosche RHYTHM+ to the limit; comparing to lots of different products and over a variety of terrain for both running and cycling. After 3 or 4 hours I realised I was wasting my time. The results were so good! And what’s the point of comparing to another optical HRM which may be less accurate?
Visually whenever I glanced from one device to another I suspected that the Scosche might be 1bpm lower. It certainly seemed to be lower at sub 100bpm HRs but those level of HR are of little interest to sporty types. Again when going up over 170bpm the Scosche seemed maybe a tad lower.
Here is a test against a Garmin HRM-RUN worn on the Upper Arm with the Scosche in blue. The most notable difference is a slight (trivial) blip at 25:00.
Worn on the forearm we get the following again with the Scosche in blue.
I have other charts but they show the same thing.
A pretty close correlation to the HRM-RUN every time.
Looking at other tables of data with time spent in zones the variation was ALWAYS less than 1%. By that I mean that if the HRMRUN had me down as 50% of my time in Zone3 then the Scosche was more than 49% and less than 51% – and to be honest it was normally only out by 0.3% or so. Some of the errors could have been compounded or reduced by the starting times of the various sessions that may have been out by a second or so but on the whole I think I adjusted for that fairly well.
To be clear: The SCOSCHE is more accurate than the MIO/GARMIN Optical HRM. ANY other optical HRM.
Caveat: I, and others, claim this is a super-accurate device. It is. All the results are genuine and not presented selectively. HOWEVER please note that wearing it on the upper arm makes it MUCH easier for SCHOSCHE to read the correct HR than for another device to get the same level of accuracy on the wrist. so if the MIO Link had a bigger strap that would fit around your bicep it would probably show greater accuracy in that position.
I was expecting to be mildly impressed with the Scosche RHYTHM+. But it REALLY impressed me with its accuracy and wearability/comfort. I would certainly recommend it and will probably use one myself from time to time.
No other optical HRM been has as accurate as this. It has delivered accuracy well above 160bpm, indeed to over 170bpm. Most other devices start to deviate too much at those levels.
I have medium-dark skin, not tattooed and with some hair – if you have different experiences, please let me know.
Why is the Scosche better than the rest? A: more lights that are better spaced further apart than the rest.
It’s a bit on the expensive side but most good products tend to be priced that way 🙂