# VO2 Max Training vs 4x4 Timer Interval Training

The clearest difference is review sentiment: VO2 Max Training at 100% against 4x4 Timer Interval Training's 0%. VO2 Max Training also leads on rating (4.6 vs 2.0) and ratings volume (7 vs 1). 4x4 Timer Interval Training's advantage is in-app purchases (none vs 6) and iOS requirement (13.0 vs 18.0). On price, ads and device support there is nothing between them.

Both are free to download. VO2 Max Training sells 6 in-app purchases, starting at $0.99 per month. 4x4 Timer Interval Training asks for nothing beyond the download.

VO2 Max Training holds the better App Store score, 4.6 against 2.0. That said, the two scores are not equally well evidenced: VO2 Max Training has 7 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 100% of VO2 Max Training's written reviews are positive against 0% of 4x4 Timer Interval Training's.

## The numbers

| Metric | VO2 Max Training | 4x4 Timer Interval Training |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.6 (7 ratings)](https://appshunter.io/ios/app/vo2-max-training-peakvo2/id6532617265/reviews)** | [2.0 (1 ratings)](https://appshunter.io/ios/app/4x4-timer-interval-training/id6759710803/reviews) |
| Number of ratings | **7** | 1 |
| Positive reviews | **100.0% of reviews** | 0.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 4 days | — |
| Monetization | Free with in-app purchases | **Free** |
| Size | 16 MB | 12 MB |
| Requires iOS | 18.0 | **13.0** |
| Devices | iPhone, Apple Watch | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Cristian Serb](https://appshunter.io/developer/294833680) | [Kesem Solutions Pty Ltd](https://appshunter.io/developer/1751494198) |

## What reviewers say

### VO2 Max Training

[App page](https://appshunter.io/ios/app/vo2-max-training-peakvo2/id6532617265)

This app provides science-backed interval training protocols to improve cardiovascular fitness and long-term health. It guides users through warm-ups, work intervals, and cool-downs with customizable timers and activity tracking.

**Highlights:** Science-backed interval protocols (Norwegian 4x4, Tabata, HIIT), Color-coded workout timer with phase transitions, Activity tracking with streaks and progress, Supports running, cycling, rowing, and indoor cardio, Fitness age estimation

**Features:** Apple Watch app

**In-app purchases (6)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlimited | $0.99 | per month |
| Unlimited | $3.99 | per month |
| Unlimited | $4.99 | per 3 months |
| Unlimited | $8.99 | per year |
| Unlimited | $11.99 | per 6 months |
| Lifetime | $17.99 | one-time |


### 4x4 Timer Interval Training

[App page](https://appshunter.io/ios/app/4x4-timer-interval-training/id6759710803)

This app provides a simple, distraction-free interval timer for the Norwegian 4x4 training protocol. It guides users through 4 minutes of intense effort followed by 4 minutes of rest, repeated four times, to improve cardiovascular fitness and VO₂ max. The minimal interface ensures focus on the workout.

**Highlights:** Simple 4x4 interval timer, Clear ON/OFF phase guidance, Optional sound cues, Large, easy-to-read timer, Session progress tracking, Minimal interface

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

**In-app purchases:** none


## Frequently asked questions

### Is VO2 Max Training free?

VO2 Max Training is free to download, with in-app purchases available.

### Is 4x4 Timer Interval Training free?

4x4 Timer Interval Training is free to download, with no in-app purchases.

### Which has better reviews, VO2 Max Training or 4x4 Timer Interval Training?

VO2 Max Training is rated higher. VO2 Max Training averages 4.6 out of 5 from 7 ratings, while 4x4 Timer Interval Training averages 2.0 from 1 ratings.

### Do VO2 Max Training or 4x4 Timer Interval Training have ads?

Neither VO2 Max Training nor 4x4 Timer Interval Training shows ads.

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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.*