# Rhythm SYNC. vs Spren Body Composition Scanner

The clearest difference is rating: Spren Body Composition Scanner at 4.7 against Rhythm SYNC.'s 1.8. Spren Body Composition Scanner also leads on review sentiment (46% vs 13%) and update cadence (every 9 days vs every 3 months). Rhythm SYNC.'s advantage is in-app purchases (none vs 14) and iOS requirement (12.0 vs 17). On price, ads and device support there is nothing between them.

Both are free to download. Spren Body Composition Scanner sells 14 in-app purchases, starting at $10.49 per month. Rhythm SYNC. asks for nothing beyond the download.

Spren Body Composition Scanner holds the better App Store score, 4.7 against 1.8. That said, the two scores are not equally well evidenced: Spren Body Composition Scanner has 1.5K ratings behind it against 128, so its average is the more settled of the two. Written reviews point the same way: 13% of Rhythm SYNC.'s written reviews are positive against 46% of Spren Body Composition Scanner's.

Rhythm SYNC. ships an update every 3 months, Spren Body Composition Scanner every 9 days. The most recent releases landed on September 3, 2026 and September 19, 2026 respectively.

## The numbers

| Metric | Rhythm SYNC. | Spren Body Composition Scanner |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [1.8 (128 ratings)](https://appshunter.io/ios/app/rhythm-sync/id1226606963/reviews) | **[4.7 (1.5K ratings)](https://appshunter.io/ios/app/spren-body-composition-scanner/id1664503999/reviews)** |
| Number of ratings | 128 | **1.5K** |
| Positive reviews | 13.1% of reviews | **46.5% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 9 days** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 47 MB | 207 MB |
| Requires iOS | **12.0** | 17 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 17+ |
| Developer | [Scosche](https://appshunter.io/developer/340018842) | [Elite HRV Inc](https://appshunter.io/developer/868829973) |

## What reviewers say

### 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


### Spren Body Composition Scanner

[App page](https://appshunter.io/ios/app/spren-body-composition-scanner/id1664503999)

This app uses your smartphone to measure body fat percentage, BMI, and body composition. It provides detailed health reports, tracks weight loss, and offers personalized nutrition plans, acting as a smart scale alternative with research-grade analysis.

**Highlights:** Body fat percentage measurement, BMI calculator, Body composition analysis, Weight tracking, Personalized nutrition planning, Multi-page PDF reports

**Features:** Apple Wallet, Vision Pro support

**In-app purchases (14)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Scan Essentials | $10.49 | per month |
| Monthly | $14.99 | per month |
| Monthly | $19.99 | per month |
| 24/7 AI coaching support | $20.99 | per month |
| Monthly | $24.99 | per month |
| Scan Essentials | $38.99 | per year |
| Quarterly | $59.99 | per 3 months |
| Annual | $69.99 | per year |
| Semiannual | $89.99 | per 6 months |
| Annual | $119.99 | per year |
| 24/7 AI coaching support | $129.00 | per year |
| Body Composition Analysis | $8.99 | one-time |
| Body Composition Analysis | $17.99 | one-time |
| Body Composition Analysis | $35.99 | one-time |

**What reviewers like**

- 👍 Easy to operate
- 🚀 Motivating
- 👍 Incredible app
- 👍 Accurate
- 👍 Talks you through the scan

**What reviewers complain about**

- 🐛 No login possible
- 🐛 Doesn't work
- 🐛 Measurements are nowhere close to DEXA scans
- 🐛 Can't delete account
- 🐛 Useless

**Reported bugs**

- No login possible
- Doesn't work
- Measurements are nowhere close to DEXA scans
- Can't delete account
- Useless

**Requested features**

- Integration with Apple Health for weight tracking
- Demo or trial before subscription
- Monthly subscription option


## Frequently asked questions

### Is Rhythm SYNC. free?

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

### Is Spren Body Composition Scanner free?

Spren Body Composition Scanner is free to download, with in-app purchases available.

### Which has better reviews, Rhythm SYNC. or Spren Body Composition Scanner?

Spren Body Composition Scanner is rated higher. Rhythm SYNC. averages 1.8 out of 5 from 128 ratings, while Spren Body Composition Scanner averages 4.7 from 1.5K ratings.

### Do Rhythm SYNC. or Spren Body Composition Scanner have ads?

Neither Rhythm SYNC. nor Spren Body Composition Scanner shows ads.

### Which is updated more often, Rhythm SYNC. or Spren Body Composition Scanner?

Rhythm SYNC. ships an update every 3 months, and Spren Body Composition Scanner every 9 days. Most recently, Rhythm SYNC. was updated on September 3, 2026 and Spren Body Composition Scanner on September 19, 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.*