Scosche Rhythm 24 | Opinion | Optical HRM 2018

Scosche Rhythm 24 Review

Scosche have just announced a successor to the highly successful RHYTHM+ armband (Source: This post will take some of the key points about the new RHYTHM 24 arm band and add some initial thoughts prior to more of a hands-on in Q2.2018 when it should be available to review in a non-beta version.

Consumer optical heart rate monitoring (oHRM) has hit the big time over the last few years and I’ve been lucky enough to follow it from the start with PulseOn and others. For some reason I’m interested in optical HR and HRV. But the reason that OHR has taken off is that optical HR has allowed HR to be more easily measured by regular consumers in places other than on the chest with a chest strap. Many of you simply don’t want to wear and extra device (strap) or simply don’t like or get on with chest straps for a variety of reasons.

Thus very many sports and activity devices have incorporated optical HR, mostly into watches. Unfortunately doing that on the wrist offers VERY significant challenges to getting accurate data to the extent where results from one device can be awesome with you or poorly performing with me.

From Valencell

However if we move that optical HR somewhere else, like the upper arm, then there is MUCH less physical movement involved and slightly juicier blood vessels for the oHRM to shine some light onto and mesauring what is reflected – and that’s ultimately how optical heart rate sensors work. The original Scosche product seemingly had super-great accuracy. It did. But it’s job was made easier because of the location where it was worn. Valencell’s sensor was then ported to other devices like Suunto SPARTANs on people’s wrist and the results with that Valencell sensor were not always so great – just like with Garmin’s Elevate sensors and everyone else’s flavour of OHR.

As well has having an accurate product, Scosche also transmitted the HR data over Bluetooth SMART and over ANT+.

And with those key features in place: an accurate location for measuring; a decent sensor; and dual-band transmission Scosche did VERY well, selling many thousands of units.

Wearable Technology - How it Works
Diagram: A Bit More About PerformTEK (Source Valencell)

With the arrival of Polar’s awesome OH1 and possibly/probably also with Wahoo’s TICKR Fit it was time for Scosche to release the new Rhythm – truth is they have probably been working on it for years.


Things are less easy now. Technology has moved on. On my desk I have an as yet unreleased and unbranded optical HR sensor for the arm – maybe rrp £30? It’s dual band. Maybe it’s not quite as good as the previous Scosche Rhythm+ but I could use it. The competition for Scosche’s place in the market will continue to hot up

Things have also moved forwards in the world of CHEST heart rate monitors some of which:

  • cache data and later re-broadcast & synchronise it back to a watch (swimming, team sports, gym classes); or
  • produce motion estimates from movements  that could give cycling cadence and even relatively complex running metrics (VO, GCT);
  • produce HRV levels of detail or are more sensitive;
  • act as signal converting devices; and/or
  • have touch related functionality (eg tap to lap).

So what new in the new Scosche?

  • Latest PerformTEK sensor from Valencell, presumably the same one used by Suunto’s latest SPARTANs (TBC)
  • Whopping 24 hour battery life
  • More LEDs to indicate HR Zone
  • Workout caching (presumably to selected Garmin devices via ANT+)
  • Supports RunKeeper, Map My Fitness, Strava and all other apps that support Bluetooth Smart
  • RR Beats (HRV, at rest)
  • IP68 sweatproof/waterproof – just about good enough for swimming…no diving please.
  • Five changeable training/use zones/modes and two multi-modes

What’s Missing

It has all I would have hoped for.

I’m not quite sure of the standards, if any, that exist for caching of Bluetooth based apps (like Polar BEAT). That’s one important area for the future that might be of interest to Scosche, this would specifically tap into the needs of GYM CLASS market.

Integration with the Apple Watch could also be interesting. Sure the Apple Watch has an oHRM but the Scosche will likely perform better and save the battery life on the Apple. I’d hope for an Apple Watch app with caching over BLE (if possible).

A bit of clarity on the HRV would be good. Theoretically the Scosche can periodically measure HRV (RMSSD) overnight. For starters, this stops the need for a waking HRV reading. BUT BUT BUT. By tracking falling-asleep HRV you can see the recovery from then to waking. That recovery may well correspond to adaptation in some way and hence you getting fitter before your very eyes. Or not. (EMFIT has a measure of integrated overnight recovery which is similar to what I describe.) No THAT IS super-cool….in my opinion.


Looks Great.

All that can go wrong is the performance. Which I doubt. Let’s wait and see.


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16 thoughts on “Scosche Rhythm 24 | Opinion | Optical HRM 2018

  1. “Whopping 24 hour battery life – which beats all the arm band sensors hands down”
    Isn’t the tickr fit quoted as 30 hours?

  2. Hi, so now we have a accurate HR strap that can be worn throughout the night (around my arm) prior to an early morning hrv test? And provide accurate results?

    My Mrs is getting peed off at me thumbling around fitting my conventional HR strap at 4.30 am prior to my hrv test?



    1. not quite. it’s better than that.
      like emfit it will periodically b able to do hrv throughout the night 9read my emfit review for a falvour) ie wont rely on one value that could be wrong
      that’s the theory.

      1. i think they are say $/£/Eu99 kind of level which I think is a bit too expensive.
        it will fall probably to the same level as the wahoo tickr fit after things settle down

  3. We all know by now about the defective production about scosche 24, my scosche 24 broke while swimming and it was gone forever, I contacted scosche thinking they will send me a replacement, after all it was a lemon product (lemon item most likely) but they said not. I have to contact the credit company because the transaction very recently and most likely I will get the money back. Just to let you know when you buy from these guys you aren’t getting a warranty. Amazing. My recommendation would be to stay away even further than sugar. Clevertraining doesn’t take responsibility of this device, many scosche24 are lemon of the production line, you guys can check in at dcrainmaker. What a horrible dreadful team Scosche and Clevertraning are.

      1. Ah yeah, I’ve been reading that. I’m hoping most of the issues people are having are just with the “advanced” features. So I’m hoping to hear whether it’ll function properly as just a plain ol’ HRM.

  4. trouble keeping heart rate while swimming. It keeps going away while swimming. Shows up again when I stop. I have it synced to my Polar V800. Worked find during run and bike. Anyone else have this problem?

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