# VO2 Max Trainer vs 4x4 Timer Interval Training

The clearest difference is rating: VO2 Max Trainer at 4.0 against 4x4 Timer Interval Training's 2.0. VO2 Max Trainer also leads on ratings volume (4 vs 1). 4x4 Timer Interval Training's advantage is in-app purchases (none vs 7) and iOS requirement (13.0 vs 18.6). On price, review sentiment, ads and device support there is nothing between them.

Both are free to download. VO2 Max Trainer sells 7 in-app purchases, starting at $1.99 per 7 days. 4x4 Timer Interval Training asks for nothing beyond the download.

VO2 Max Trainer holds the better App Store score, 4.0 against 2.0. Both are backed by a comparable volume of ratings — 4 and 1 respectively. Written reviews split almost evenly too, at 0% and 0% positive.

## The numbers

| Metric | VO2 Max Trainer | 4x4 Timer Interval Training |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.0 (4 ratings)](https://appshunter.io/ios/app/vo2-max-trainer-hiit-zone-2/id6736629740/reviews)** | [2.0 (1 ratings)](https://appshunter.io/ios/app/4x4-timer-interval-training/id6759710803/reviews) |
| Number of ratings | **4** | 1 |
| Positive reviews | 0.0% of reviews | 0.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Weekly | — |
| Monetization | Free with in-app purchases | **Free** |
| Size | 286 MB | 12 MB |
| Requires iOS | 18.6 | **13.0** |
| Devices | iPhone, iPad, Apple Watch | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Kevin Floch](https://appshunter.io/developer/1772752224) | [Kesem Solutions Pty Ltd](https://appshunter.io/developer/1751494198) |

## What reviewers say

### VO2 Max Trainer

[App page](https://appshunter.io/ios/app/vo2-max-trainer-hiit-zone-2/id6736629740)

Measure, track, and improve your VO2 Max with a variety of fitness tests and personalized training plans. Features include HIIT and Zone 2 workouts, progress tracking, and integration with Apple Watch and HealthKit.

**Highlights:** Measure VO2 Max with 5 fitness tests, HIIT and Zone 2 training, Track progress and compare to leaderboards, Apple Watch integration, HealthKit integration, Training readiness scoring, Fitness age calculation

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

**In-app purchases (7)**

| Purchase | Price | Billing |
| --- | --- | --- |
| VO2_Weekly | $1.99 | per 7 days |
| VO2_Monthly | $1.99 | per month |
| VO2_Annually | $14.99 | per year |
| VO2_Lifetime_Upgrade | $9.99 | one-time |
| VO2_Lifetime_Upgrade2 | $14.99 | one-time |
| VO2_Lifetime | $19.99 | one-time |
| VO2_Lifetime2 | $29.99 | 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 Trainer free?

VO2 Max Trainer 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 Trainer or 4x4 Timer Interval Training?

VO2 Max Trainer is rated higher. VO2 Max Trainer averages 4.0 out of 5 from 4 ratings, while 4x4 Timer Interval Training averages 2.0 from 1 ratings.

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

Neither VO2 Max Trainer 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.*