Comparison

Heart Rate Variability Logger vs Intervall

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

Head to head
About

Heart Rate Variability Logger

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
Read full description

Heart Rate Variability Logger lets you record, plot and export time, frequency and non-linear HRV Features (includes experience sampling, RR-interval correction, DFA alpha 1 for aerobic threshold estimation in real-time, comparison between recordings, activity monitoring & step counting, location tracking). Heart Rate Variability Logger requires a Bluetooth Low Energy (also called Bluetooth Smart or BLE or 4.0) heart rate sensor (we recommend Polar H7 or H10) Main features: - Extracts, plots, stores and exports heart rate, rr-intervals, time and frequency domain heart rate variability features (AVNN, SDNN, rMSSD, pNN50, LF, HF, LF/HF, alpha 1 from DFA) - Configurable experience sampling for events annotation - Comparison between up to 3 recordings lets you get a better understanding of differences in HRV under different contexts in a glance. The comparison modality includes also Outlier removal - Activity tracking: step counter or accelerometer derived motion intensity for user context (step counter only for iPhones 5S) - Location tracking, either using GSM/WiFi networks (low battery consumption) or GPS (high accuracy) - Configurable time window for features computation (choose between 30 seconds, 1, 2 or 5 minutes) - RR-intervals correction can be enabled to prevent ectopic beats or artifacts from affecting HRV features - export for Kubios - Filters data based on the selected threshold - Shows HR in the app icon - Data export using iTunes or Dropbox - Tested for recordings longer than 24 hours Please note that continued use of GPS running in the background can dramatically decrease battery life.

About

Intervall

Create and run custom interval training routines with a clear, legible timer. This app syncs with Apple Watch to display heart rate and control workouts, and can save data to Apple Health.

Highlights
  • Custom interval workouts
  • Save and reuse workouts
  • Large, readable timer
  • Apple Watch mirroring
  • Watch controls
  • Live heart rate display
  • Apple Health integration
Features
Read full description

Intervall is a precise interval timer for training sessions on iPhone and Apple Watch. Build custom workouts from intervals, repeats, and rests, then run them with a clear timer designed to stay legible during movement. Features: • Build custom interval workouts with sets, repeats, and rest periods • Save workouts and return to them anytime • Run workouts on iPhone with large, readable timer controls • Mirror the session on Apple Watch • Control play, pause, and skipping from your watch • View live heart rate when a fresh reading is available from Apple Watch Intervall is suited to HIIT, circuits, mobility work, cardio intervals, strength blocks, and other structured workouts. Health and Apple Watch: The Watch companion can supply live heart rate during a workout. Without a Watch reading, the heart rate display stays hidden. When you run a workout on iPhone without the Watch, Intervall can save it to Apple Health.

Screenshots

Heart Rate Variability Logger4 screens
Intervall4 screens

Verdict

The call

The clearest difference is price: Intervall at Free against Heart Rate Variability Logger's $9.99. Intervall also leads on rating (5.0 vs 3.5). Heart Rate Variability Logger's advantage is update cadence (fortnightly vs every 3 months) and ratings volume (19 vs 1). On ads, in-app purchases and device support 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

Intervall is free to download; Heart Rate Variability Logger costs $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Intervall holds the better App Store score, 5.0 against 3.5. That said, the two scores are not equally well evidenced: Heart Rate Variability Logger has 19 ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

Heart Rate Variability Logger ships an update fortnightly, Intervall every 3 months. The most recent releases landed on October 14, 2026 and October 2, 2026 respectively.

Scorecard6 real differences · 4 level
Heart Rate Variability Logger versus Intervall: the parameters behind the verdict, then further details
ParameterHeart Rate Variability LoggerIntervall
Price$9.99Free — better
Rating3.5 (19 ratings)5.0 (1 ratings) — better
Positive reviews43.1% of reviews—
Number of ratings19 — better1
Update frequencyFortnightly — betterEvery 3 months
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, iPod, Apple Watch — betteriPhone, Apple Watch
Requires iOS15.6 — better18.0
Further details — not scored
Size10 MB4 MB
Age rating4+4+
DeveloperA.S.M.A. B.V.Ruben Musca

Customer experience

Heart Rate Variability Logger

All ratings19 ratings
Positive63.2%
Neutral0.0%
Negative36.8%
Written reviews58 reviews
Positive43.1%
Neutral6.9%
Negative50.0%

Intervall

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Heart Rate Variability Logger

No in-app purchases

None

Intervall

No in-app purchases

Questions

Is Heart Rate Variability Logger free?
Heart Rate Variability Logger costs $9.99, with no in-app purchases.
Is Intervall free?
Intervall is free to download, with no in-app purchases.
Which has better reviews, Heart Rate Variability Logger or Intervall?
Intervall is rated higher. Heart Rate Variability Logger averages 3.5 out of 5 from 19 ratings, while Intervall averages 5.0 from 1 ratings.
Do Heart Rate Variability Logger or Intervall have ads?
Neither Heart Rate Variability Logger nor Intervall shows ads.
Which is updated more often, Heart Rate Variability Logger or Intervall?
Heart Rate Variability Logger ships an update fortnightly, and Intervall every 3 months. Most recently, Heart Rate Variability Logger was updated on October 14, 2026 and Intervall on October 2, 2026.

Other comparisons