Comparison

Heart Graph vs Rhythm SYNC.

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Heart Graph

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
Read full description

Knowing your current heart rate is useful, but seeing in real time how it varies over a longer period gives you much more information, especially when trying to understand how your body is responding to a training plan. Heart Graph can be used for all types of aerobic exercise including running, cycling, rowing or gym work, and of course you can also use it to study your normal heart rate for general health reasons. Heart Graph allows you to record new data and see your heart rate graph in real time, as well as importing existing data from Apple Health. Data from previous sessions can then be compared to give a deeper understanding of how your body is changing over time, for example by directly comparing the graphs for equivalent sessions, viewing statistics such as max, mean and resting heart rate across sessions, or seeing the proportion of time spent in different heart rate zones aggregated over weeks or months. (Note some features require a one-off In-App Purchase, as described below.) FREE features of Heart Graph include: * Display a real-time graph of heart rate against time on your iPhone or iPad * Support for both Bluetooth sensors and Apple Watch * No ads * Review your sessions offline to spot trends in your data * Integration with Apple Health: import existing workout data and store new workouts * Maximise the screen area for graphs on iPhone using landscape orientation * Group related sessions by adding your own notes, then searching for sessions matching those notes * Record a standard Reference Set at the start of each session to help determine how your body is really doing; if your heart rate is elevated, you may want to take it easy * Record data in the background if you want to use other heart rate apps (Bluetooth sensors) * Calculate calories burned, and set a calorie target for each session Beyond the basics, a single, one-off In-App Purchase will enable the Premium Features, giving you access to more in-depth analysis tools and the ability to design your training sessions in the app. These Planned Workouts split a session into small pieces, for example sets at the the gym, or intervals on a bike. When you’re exercising, Heart Graph will keep track of where you are in the session and what’s coming up next, alerting you when it’s time to stop or move on. The trigger for moving from one set to the next can be a simple time gap (“wait 30 seconds”), or be based on heart rate to allow a specific amount of recovery before continuing (“wait until heart rate is below 120bpm”). The outcome is a structured plan that adapts to how your body is responding each time you do that session. Premium Features include: * View and analyse the time spent in each of five configurable heart rate zones * Add annotations to the graph during recording to help identify key events * Heart rate alarms when your heart rate changes zone or goes above or below configurable thresholds * Import data from the Health app for custom time periods of up to 24 hours * Directly compare graphs for equivalent sessions * Compare statistics (such as max, mean and resting heart rate) across sessions * Record a session to explicitly measure resting heart rate while you relax * Audio rep counting so you never lose count - make a noise every time you complete a rep and the app keeps track of how many you’ve done * Import and export heart rate data from other apps or your computer using Garmin TCX format files * Import Garmin GPX format files * Export data to CSV files for further analysis in software such as Excel (email, Dropbox, etc) Heart Graph requires an external sensor to record heart rate, such as: * A bluetooth (BTLE) sensor such as the Wahoo Tickr / Polar H10 chest straps, or the Mio Alpha watch * An Apple Watch * An ANT+ sensor connected using the Wahoo Key DISCLAIMER: Heart Graph is not a medical device, and you must always seek a doctor’s advice before making any medical decisions.

About

Rhythm SYNC.

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
Read full description

The award-winning Rhythm Heart Rate Monitors use patented technology to capture exceptionally accurate performance in both wet and dry conditions. This Scosche Rhythm Sync app: · Connects to Rhythm 24 and Rhythm+ Heart Rate Monitors · Manages Rhythm 24 activity modes and biometrics functionality: Heart Rate Only, Running, Cycling, Swimming, Heart Rate Variability, Duathlon, and Triathlon · Displays heart rate data from your Rhythm Monitors · Displays Rhythm battery level · Configures sharing with compatible heart rate tracking apps, fitness watches, bike computers, and fitness equipment, to stream your fitness-data in real time, track heart rate history, and more! · Collects Rhythm 24 recorded activities and has download capabilities · Allows for Rhythm Heart Rate Monitors software and firmware updates · HealthKit integration which allows you save workout data recorded on the sensor.

Screenshots

Heart Graph4 screens
Rhythm SYNC.4 screens

Verdict

The call

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.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

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

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard8 real differences · 2 level
Heart Graph versus Rhythm SYNC.: the parameters behind the verdict, then further details
ParameterHeart GraphRhythm SYNC.
PriceFreeFree
Rating4.5 (1.2K ratings) — better1.8 (128 ratings)
Positive reviews86.5% of reviews — better13.1% of reviews
Number of ratings1.2K — better128
Update frequencyEvery 2 weeks — betterEvery 3 months
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesFree — better
DevicesiPhone, iPad, iPod, Apple Watch — betteriPhone, iPod
Requires iOS15.012.0 — better
Further details — not scored
Size33 MB47 MB
Age rating4+4+
DeveloperSmoky Cat Software Ltd.Scosche

Customer experience

Heart Graph

All ratings1,199 ratings
Positive88.3%
Neutral2.8%
Negative8.9%
Written reviews563 reviews
Positive86.5%
Neutral3.7%
Negative9.8%

Rhythm SYNC.

All ratings128 ratings
Positive16.4%
Neutral1.6%
Negative82.0%
Written reviews99 reviews
Positive13.1%
Neutral1.0%
Negative85.9%

User reviews

Heart Graph

From 1.2K App Store ratings

What we love

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

Room to improve

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

Rhythm SYNC.

From 128 App Store ratings

What we love

  • ✅ 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)

Room to improve

  • 🐛 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

Bugs and requests

Heart Graph

Reported bugs

2 issues
  • Workouts not always syncing correctly
  • App crashes or freezes on some devices

Requested features

4 requests
  • 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.

Reported bugs

17 issues
  • 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
Show 12 more
  • Custom heart rate zones not applied to recordings
  • Battery level shows as zero or incorrect
  • Settings menu items non-functional or unresponsive
  • App loses connection when device syncs with other apps
  • Data disappears when monitor disconnects
  • Export to CSV ignores custom zones
  • App crashes when attempting to share workout data
  • Last mode setting not remembered between sessions
  • Unable to modify personal details (height, weight, birthday)
  • Incompatibility with iPhone X and newer models
  • Firmware update window won't open
  • App incompatible with iOS 11 and newer versions

Requested features

12 requests
  • 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
Show 7 more
  • Auto-sync feature when device is detected
  • Detailed analytics and charts
  • Better user profile settings (height, weight, age)
  • Dark mode option
  • Improved troubleshooting and help documentation
  • Ability to delete saved connections to health apps
  • Support for multiple languages in documentation

In-app purchases

2 purchases

Heart Graph

One-time2
  • Support Ad-Free Software$0.99
  • Premium Features$2.99
None

Rhythm SYNC.

No in-app purchases

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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