# Heart Graph vs Rhythm SYNC.

The clearest difference is review sentiment: Heart Graph at 87% against Rhythm SYNC.'s 13%. Heart Graph also leads on rating (4.5 vs 1.8) and update cadence (every 2 weeks vs every 3 months). Rhythm SYNC.'s advantage is in-app purchases (none vs 2) and iOS requirement (12.0 vs 15.0). On price and ads there is nothing between them.

Both are free to download. Heart Graph sells 2 one-off in-app purchases. Rhythm SYNC. asks for nothing beyond the download.

Heart Graph holds the better App Store score, 4.5 against 1.8. That said, the two scores are not equally well evidenced: Heart Graph has 1.2K ratings behind it against 128, so its average is the more settled of the two. Written reviews point the same way: 87% of Heart Graph's written reviews are positive against 13% of Rhythm SYNC.'s.

Heart Graph ships an update every 2 weeks, Rhythm SYNC. every 3 months. The most recent releases landed on September 24, 2026 and September 3, 2026 respectively.

## The numbers

| Metric | Heart Graph | Rhythm SYNC. |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (1.2K ratings)](https://appshunter.io/ios/app/heart-graph/id591655999/reviews)** | [1.8 (128 ratings)](https://appshunter.io/ios/app/rhythm-sync/id1226606963/reviews) |
| Number of ratings | **1.2K** | 128 |
| Positive reviews | **86.5% of reviews** | 13.1% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 2 weeks** | Every 3 months |
| Monetization | Free with in-app purchases | **Free** |
| Size | 33 MB | 47 MB |
| Requires iOS | 15.0 | **12.0** |
| Devices | **iPhone, iPad, iPod, Apple Watch** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Smoky Cat Software Ltd.](https://appshunter.io/developer/508703406) | [Scosche](https://appshunter.io/developer/340018842) |

## What reviewers say

### Heart Graph

[App page](https://appshunter.io/ios/app/heart-graph/id591655999)

Track your heart rate in real-time and analyze trends over time. Understand your body's response to training and general health with detailed graphs and statistics. Import data from Apple Health for a comprehensive view of your fitness journey.

**Highlights:** Real-time heart rate graphing, Apple Health integration, Session comparison and statistics, Heart rate zone analysis, Planned workout design, Heart rate alarms, Background data recording

**Features:** macOS Compatibility, Apple Watch app

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Support Ad-Free Software | $0.99 | one-time |
| Premium Features | $2.99 | one-time |

**What reviewers like**

- 👍 Excellent for heart rate monitoring
- 🚀 Reliable and accurate data
- 💡 Customizable heart rate zones
- 🔒 No data collection or ads
- 👍 Simple and intuitive interface

**What reviewers complain about**

- 🐛 Occasional connectivity issues
- 🐛 Calorie calculations can be inaccurate
- 🔋 Battery drain on some devices
- 👎 Limited free version, premium features require payment

**Reported bugs**

- Workouts not always syncing correctly
- App crashes or freezes on some devices

**Requested features**

- Add minimum heart rate to metrics
- Integrate with more fitness apps and devices
- Improve customization options for workout labels
- Display heart rate on the workout selection screen


### Rhythm SYNC.

[App page](https://appshunter.io/ios/app/rhythm-sync/id1226606963)

This app connects to heart rate monitors to display real-time data, manage activity modes, and track workout history. It allows for software updates and integrates with HealthKit for saving workout data.

**Highlights:** Connects to Rhythm 24 and Rhythm+ monitors, Manages activity modes and biometrics, Displays heart rate and battery level, Configures data sharing with other apps, Collects and downloads recorded activities, Performs software and firmware updates, HealthKit integration

**In-app purchases:** none

**What reviewers like**

- ✅ Accurate heart rate readings
- 🔋 Long-lasting device battery life
- 🔄 Reliable device hardware
- 📱 Simple and straightforward interface
- 🔗 Works well with third-party apps (Peloton, Garmin, Apple Watch)

**What reviewers complain about**

- 🐛 Frequent Bluetooth connection failures
- 🐛 App crashes and freezes regularly
- ❌ App doesn't recognize connected devices
- ⚠️ HRV mode difficult or impossible to access
- 📊 Extremely limited app functionality

**Reported bugs**

- App fails to detect device despite Bluetooth connection
- Bluetooth connection drops frequently during workouts
- App crashes on startup (splash screen freeze)
- Firmware update fails repeatedly
- HRV readings not displaying or accessible

**Requested features**

- HRV (Heart Rate Variability) mode that actually works
- Comprehensive workout history and logging
- Data export to multiple health apps (MyFitnessPal, TrainingPeaks, etc.)
- Customizable heart rate zones that persist
- Batch download and export of multiple files


## Frequently asked questions

### Is Heart Graph free?

Heart Graph is free to download, with in-app purchases available.

### Is Rhythm SYNC. free?

Rhythm SYNC. is free to download, with no in-app purchases.

### Which has better reviews, Heart Graph or Rhythm SYNC.?

Heart Graph is rated higher. Heart Graph averages 4.5 out of 5 from 1.2K ratings, while Rhythm SYNC. averages 1.8 from 128 ratings.

### Do Heart Graph or Rhythm SYNC. have ads?

Neither Heart Graph nor Rhythm SYNC. shows ads.

### Which is updated more often, Heart Graph or Rhythm SYNC.?

Heart Graph ships an update every 2 weeks, and Rhythm SYNC. every 3 months. Most recently, Heart Graph was updated on September 24, 2026 and Rhythm SYNC. on September 3, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*