# Zx: Heart Rate Zones Training — user reviews > 21 indexed App Store user reviews of Zx by OverSphere LLC, rated 4.30/5 from 70 ratings. - Source: https://appshunter.io/ios/app/zx-heart-rate-zones-training/id1457355997/reviews - App overview in markdown: https://appshunter.io/ios/app/zx-heart-rate-zones-training/id1457355997.md - Rating breakdown: 5★ 48 · 4★ 9 · 3★ 4 · 2★ 5 · 1★ 4 ## Newest reviews (1 of 21) ### 4/5 — Like this app *2022-09-21, version 1.4.12* 4 stars. Would give 5 stars if the colored bars in the workout graph also displayed the target heart rate zones like the Polar Beat app. does. ## Most critical reviews (10 lowest-rated) ### 1/5 — Custom and community workouts not showing on my watch *2024-06-26, version 1.5* I’m not able to use the custom and community workouts after paying for this app because they don’t show up on my watch. 😕 ### 1/5 — Eh *2023-10-20, version 1.5* I got this app thinking it would give me realtime workout info on what zone I am in and for how many minutes. It’s just like all the other apps. you can only see what zone you are in at that exact moment. It’s not realtime info (the kind you can use to guide your workout ### 1/5 — Rip off *2023-07-20, version 1.5* I was looking for something to exactly what this app should do, if it worked! But the studio (self-created) workouts don’t work! They don’t sync with your phone and when you open it on your watch it just spins.. waiting for you to start the workout (that does not appear) on your watch. Biggest waste of $15. I tried to contact support but my email was bounced back and the link from the App Store leads to a page that says coming soon. I’m going to try to request a refund because this is so pointless. A shame because I would have gladly paid the $15 for something that worked as expected. ### 1/5 — Leider nicht kann ich diese App nicht empfehlen *2020-10-14, version 1.3.5* Brustband für die Herzmessung wird nicht erkannt, App kann also prinzipiell nicht verwendet werden. Des Weiteren synchroniseren Watch und App nicht. Komplett wertlos ### 2/5 — Support did not respond *2023-06-07, version 1.5* I contacted support about the zone categories double the amount of time I worked out in each zone. I sent a screen shot showing that I worked out 6 minutes in the intensity zone according to my custom heart rate and it recorded over 12 minutes. I requested help and the answer was “crickets”…I’ve been totally ghosted. I would have rated the app a 4 star, otherwise. ### 2/5 — Overrated *2020-06-03, version 1.2.2* The app does nothing special that the normal Apple Watch workout app does not do. It’s designed poorly, there are few glitches. Do not bother buying. ### 3/5 — Fehler in der HR Darstellung *2021-05-10, version 1.4.7* Beginnt man ein Training, wird die Herzfrequenz abgeschnitten dargestellt. Genau in gleicher Höhe wie das Herzsymbol. Dadurch kann man die Herzfrequenz nicht erkennen. Auf iPhone SE 2020 ### 3/5 — :( *2020-03-26, version 1.2* App shut down when editing ### 4/5 — Good simple interface-some iwatch sync issues *2024-03-01* Love the clear interface on the app. Can’t seem to sync studio and community workouts to my iwatch however. **Developer response:** Hello Bents76! Thanks for using Zx! We are aware of sync issues users are having and it not being as fast as it used to be. It may take awhile but workouts should eventually sync to your Watch. We are working on that and hopefully we can get a fix out soon. If you have any other issues or feature requests, please don't hesitate to reach out to support@oversphere.net. Best, Jillian OverSphere Support ### 4/5 — Swimming doesn't work *2023-12-13, version 1.5* App is promising. While running and cycling work fine, logging a swimming workout fails. It says "Please allow Zx to 'Write Workout Data' in Health and try again. By the way your support website is just a placeholder site. Might want to update that. In addition to the above bug, to be useful during swimming, the alerts would have to be different patterns for above and below zone, and they'd have to be constant. For example, short quick vibrations if below zone and long slow vibrates if above zone. The same kind of constant and differentiated alerts would be useful in other situations (e.g. watch under your sleeve or glove) but especially in swimming when it's not practical to look at the watch face during a lap. ## Most praised reviews (10 highest-rated) ### 5/5 — What I wanted *2025-08-03, version 1.7* Does what it says but please let us choose the language (in the app and on the watch). The German translation is confusingly wrong. ### 5/5 — Great workout companion! *2024-09-23, version 1.7* Really helpful for taking a look at hr data ### 5/5 — Fantastic app! *2024-09-13, version 1.6.1* I was looking for an interval timer for my own HIIT training that could also pair with my coros armband to show my heart rate. Paying $14 for this app seemed like a no-brainer when the cheapest watch I could find to show my heart rate was $180. Now I get to see my interval timer and heart rate in the one place. It works perfectly with my coros armband and make sure I stay in the zone during night intensity intervals (while not pushing too hard above my range). Thanks for making such an intuitive and affordable app with great functionality. ### 5/5 — Apps doesn’t work right *2022-10-30, version 1.4.12* It worked at first but no longer sync with Apple Watch ### 5/5 — A good heart *2021-08-05* A great app to help with working out within specific heart rate zones, I really like the create custom workout facility, as well as the heart rate routines provided. It was a bit fiddly figuring out why it wouldn’t connect with my Apple Watch, but issue resolved when I turned off the Bluetooth within the app settings. Thanks for a very useful app 👍 **Developer response:** Thanks for the kind words! ❤️ if you have any issues or feature requests, please don’t hesitate to reach out to support@oversphere.net. Best, OverSphere Support ### 5/5 — Funktioniert Einwandfrei *2021-03-28, version 1.4.7* Habe schon als nach einer App gesucht, mit der ich den Puls besser prüfen kann als mit der FitnessApp und bin mit dieser in Verbindung mit der Watch 5 und dem iPhone XR sehr zufrieden. ### 5/5 — Watch complication of Z Score please *2021-01-29, version 1.4.4* Watch complication of Z Score please The Zx score on the watch doesn’t match with the fitness level. For example, if I change to level 1, the iPhone app seems to be always at level 3. Please fix, thank you. ### 5/5 — Problème *2021-01-18, version 1.4.2* Je viens de me rendre compte. Que ma montre n’est pas compatible avec votre programme. J’ai un garmin. Il y a un autre façon de se connecter? ### 5/5 — Resting Heart Rate has improved *2020-02-22, version 1.1.4* Been using this app now for a couple months and my resting heart rate has gone down by quite a bit. My doctor was impressed!!! ### 5/5 — Awesome app! *2020-02-16, version 1.1.4* I’ve been waiting for something like this. The ability to make my own workouts is something missing from other zone trainer apps I’ve used. The watch interface is slick and gives me everything I need. Plus the ability to download other users creations is great when I need inspiration. Support is great with fast communication when I had a question. Definitely looking forward to seeing how the app evolves! --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-05.*