# N4x4 vs Gregs Endurance Training

The clearest difference is update cadence: N4x4 at every 3 days against Gregs Endurance Training's weekly. N4x4 also leads on iOS requirement (17.5 vs 26.4). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

N4x4 ships an update every 3 days, Gregs Endurance Training weekly. The most recent releases landed on October 4, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | N4x4 | Gregs Endurance Training |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.4 (17 ratings)](https://appshunter.io/ios/app/n4x4/id6686407796/reviews)** | — |
| Number of ratings | **17** | — |
| Positive reviews | 66.7% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 days** | Weekly |
| Monetization | Free | — |
| Size | 15 MB | 4 MB |
| Requires iOS | **17.5** | 26.4 |
| Devices | **iPhone, Apple Watch** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Jan van Rensburg](https://appshunter.io/developer/1688121173) | [Pin Oak Partners LLC](https://appshunter.io/developer/1856022647) |

## What reviewers say

### N4x4

[App page](https://appshunter.io/ios/app/n4x4/id6686407796)

This app guides you through the scientifically-backed Norwegian 4x4 HIIT protocol to efficiently boost your VO2 Max and cardiovascular health. It offers set-and-forget workouts with visual and audio cues, suitable for all fitness levels.

**Highlights:** Norwegian 4x4 HIIT protocol, Set-and-forget workout structure, Visual and audio interval cues, Real-time heart rate zone display, 5-minute warm-up, 4 rounds of 4-minute intervals, 3-minute recovery periods

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

**In-app purchases:** none


### Gregs Endurance Training

[App page](https://appshunter.io/ios/app/gregs-endurance-training/id6794333721)

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

**In-app purchases:** none


## Frequently asked questions

### Is N4x4 free?

N4x4 is free to download, with no in-app purchases.

### Is Gregs Endurance Training free?

Gregs Endurance Training is free to download, with no in-app purchases.

### Do N4x4 or Gregs Endurance Training have ads?

Neither N4x4 nor Gregs Endurance Training shows ads.

### Which is updated more often, N4x4 or Gregs Endurance Training?

N4x4 ships an update every 3 days, and Gregs Endurance Training weekly. Most recently, N4x4 was updated on October 4, 2026 and Gregs Endurance Training on October 5, 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.*