# Heart Rate Variability Logger vs mySASY training

The clearest difference is price: mySASY training at Free against Heart Rate Variability Logger's $9.99. mySASY training also leads on review sentiment (71% vs 43%). Heart Rate Variability Logger's advantage is in-app purchases (none vs 7) and chart position (#67 vs unranked). On ads, device support and iOS requirement there is nothing between them.

mySASY training is free to download; Heart Rate Variability Logger costs $9.99 up front. mySASY training sells 7 in-app purchases, starting at $0.49 per month. Heart Rate Variability Logger asks for nothing beyond the download.

Heart Rate Variability Logger ships an update fortnightly, mySASY training monthly. The most recent releases landed on October 26, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Heart Rate Variability Logger | mySASY training |
| --- | --- | --- |
| Price | $9.99 | **Free** |
| Rating | **[3.5 (19 ratings)](https://appshunter.io/ios/app/heart-rate-variability-logger/id683984776/reviews)** | — |
| Number of ratings | **19** | — |
| Positive reviews | 43.1% of reviews | **71.4% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Fortnightly** | Monthly |
| Monetization | Paid | **Free with in-app purchases** |
| Best chart rank | **#67** | — |
| Size | 10 MB | 19 MB |
| Requires iOS | 15.6 | **14.2** |
| Devices | **iPhone, iPod, Apple Watch** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [A.S.M.A. B.V.](https://appshunter.io/developer/1066843463) | [mySASY a.s.](https://appshunter.io/developer/1521468317) |

## What reviewers say

### Heart Rate Variability Logger

[App page](https://appshunter.io/ios/app/heart-rate-variability-logger/id683984776)

**Currently charting:** #67 Top Paid · Health & Fitness (US App Store)

This app records, plots, and exports heart rate variability data, including time, frequency, and non-linear features. It supports experience sampling, RR-interval correction, and activity/location tracking. Requires a compatible Bluetooth heart rate sensor.

**Highlights:** Record and plot HRV data, Extract time and frequency domain features, Experience sampling for event annotation, Compare multiple recordings, Activity and location tracking, RR-interval correction, Export data for Kubios

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases:** none


### mySASY training

[App page](https://appshunter.io/ios/app/mysasy-training/id1528683581)

Optimize your athletic performance with science-backed diagnostics. Monitor your body's readiness for training, identify optimal days for increased load, and prevent overtraining. Achieve your ambitious goals by training smarter, not just harder.

**Highlights:** Morning adaptation capacity diagnostics, Monitor body readiness for training, Identify days for increased training load, Detect negative body reactions, Prevent overtraining and fatigue, Improve training quality over quantity

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (7)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Free | $0.49 | per month |
| Basic+ 1 month | $10.99 | per month |
| Sport 1 month | $14.49 | per month |
| Basic+ 6 months | $53.99 | per 6 months |
| Sport 6 months | $71.99 | per 6 months |
| Basic+ 12 months | $79.99 | per year |
| Sport 12 months | $118.99 | per year |


## Frequently asked questions

### Is Heart Rate Variability Logger free?

Heart Rate Variability Logger costs $9.99, with no in-app purchases.

### Is mySASY training free?

mySASY training is free to download, with in-app purchases available.

### Do Heart Rate Variability Logger or mySASY training have ads?

Neither Heart Rate Variability Logger nor mySASY training shows ads.

### Which is updated more often, Heart Rate Variability Logger or mySASY training?

Heart Rate Variability Logger ships an update fortnightly, and mySASY training monthly. Most recently, Heart Rate Variability Logger was updated on October 26, 2026 and mySASY training on October 25, 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.*