# Norwegian 4x4 Protocol: Boreas — Interval training for VO2 max

> Interval training app for VO2 max improvement using the Norwegian 4x4 protocol. (iPhone/iPad app by Havard Tryman.)

- Source: https://appshunter.io/ios/app/norwegian-4x4-protocol-boreas/id6751464534 (this page in markdown: same URL + `.md`)
- Developer: [Havard Tryman](https://appshunter.io/developer/1662964293)
- Category: Sports, Health & Fitness
- Price: Free with in-app purchases
- Rating: 4.70/5 from 56 App Store ratings · 8 written reviews indexed
- Age rating: 4+
- Requires: iOS 16.6 · 9 MB
- Languages: American English
- Released: 2025-08-26
- Data updated: 2026-08-31
- Monetization: freemium
- User reviews in markdown: https://appshunter.io/ios/app/norwegian-4x4-protocol-boreas/id6751464534/reviews.md

## What is Norwegian 4x4 Protocol?

Get started with Norwegian 4x4 interval training.

Norwegian 4x4 Protocol: Boreas makes it easy to get started with the Norwegian 4x4 protocol. Just select warm-up and cooldown duration, and the app handles the rest. You can connect an Apple Watch to track your heart rate and calories. The app supports voice guidance to let you know when the interval is about to end and when the next interval starts.

Features:
• Perform Norwegian 4x4 workouts.
• Know when the next interval starts while the app is in the background with voice guidance.
• Get current heart rate, heart rate zone and calories from your Apple Watch.
• Save your workouts to the Health app.
• No sign-in is required.

Norwegian 4x4 Protocol: Boreas is a HIIT interval timer for improving cardio, which is relevant if you're training for 5k, 10k, half marathon, marathon, improving VO2 max or general fitness.

If you have a suggestion for how to improve Norwegian 4x4 Protocol: Boreas, feel free to contact the App Support email.

Always consult with a healthcare provider before starting any new exercise program. Exercise can carry risks, especially for people who have certain medical conditions or who have not been physically active in a long time. It's important to understand that using this app does not replace a doctor's advice or treatment.

Terms of use for Norwegian 4x4 Protocol: Boreas: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

## Key features

- Norwegian 4x4 workouts
- Voice guidance for intervals
- Apple Watch heart rate tracking
- Calorie tracking
- Save workouts to Health app
- No sign-in required

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Pro | $24.99 | per year |
| Pro | $8.99 | per 7 days |


## Recent user reviews (8 of 8)

All indexed reviews: https://appshunter.io/ios/app/norwegian-4x4-protocol-boreas/id6751464534/reviews.md

### 1/5 — Insulting business model

*2026-08-22*

Offering two subscription plans, one EXTREMELY weekly expensive plan to push the user to buy a (still expensive) annual plan is spitting on the user’s face.

### 4/5 — More options

*2026-07-22*

Please add more exercise options

### 5/5 — Best App for Norwegian 4x4

*2026-07-19*

This is by far the best app for doing the Norwegian 4x4 training. The alerts help to let you know how much time is left and it works flawlessly.

### 5/5 — Best Norwegian 4x4 app with incredible dev support!

*2026-06-18*

I downloaded a half dozen 4x4 apps and this one was definitely the best, but it was missing the ability to start the intervals at less than 1 minute (worried I’d give myself a heart attack lol), and he replied almost immediately and implemented the change the next day!  Incredible!

**Developer response:** Thank you for the review!

### 5/5 — It finally works!

*2026-02-25*

Just redownloaded the app and it now gets heart rate info and the workout automatically began on my watch. Impressive.

**Developer response:** Thanks for the review!

### 5/5 — Good Workout Companion

*2026-01-14*

I recently decided to try the Norwegian 4x4 protocol due to its well-documented benefits for cardiac health.  This simple app works great for me!  During energetic walks, I can listen to an audiobook, and the app sends brief notifications to start a new slow or fast phase.  It picks up my heart rate from my watch and, at the end of the workout, displays a heart rate graph showing how well I met the max heart rate guidelines: 70% for the slow phase and 85-95% for the fast phase.  The workout is sent to your iPhone’s Health Data.

At some point the app failed to get HR data. (Perhaps there was an iPhone update).  It turns out you have to give it permission to get the data.  Go to Settings->Privacy and Security->Health->Boreas and turn on options as needed. I enabled Heart Rate and others.

### 1/5 — No heart guidance??

*2026-01-08*

Allegedly tracked heart rate, but it’s not live lags quite a bit and I bought this because I thought it was gonna give me coaching if my heart rate was too higher too low to make sure I hit my heart rate without having a painter. Look at things forward working out. Couldn’t try that feature until I bought it, though which kind of ticked me off.

**Developer response:** Thank you for the feedback. The app has now been updated to display heart rate and heart rate zone in real-time on Apple Watch. There can be a slight delay in heart rate data due to how Apple's HealthKit delivers updates, but it should usually be minimal. Real-time voice coaching for heart rate zones is a great suggestion to keep in mind for future updates. Regarding trying features before buying: there is a free trial that lets you try all features before committing.

### 5/5 — Good Workout Companion

*2025-12-19*

I recently decided to try the Norwegian 4x4 protocol due to its well-documented benefits for cardiac health.  This simple app works great for me!  During energetic walks, I can listen to an audiobook, and the app sends brief notifications to start a new slow or fast phase.  It picks up my heart rate from my watch and, at the end of the workout, displays a heart rate graph showing how well I met the max heart rate guidelines: 70% for the slow phase and 85-95% for the fast phase.  The workout is sent to your iPhone’s Health Data.

## Frequently asked questions about Norwegian 4x4 Protocol

### What is the Norwegian 4x4 Protocol app?

The Norwegian 4x4 Protocol app guides you through a specific interval training method designed to improve your VO2 max and cardiovascular fitness. It allows customization of warm-up and cooldown periods, provides voice cues for intervals, and syncs with your Apple Watch.

### Does Norwegian 4x4 Protocol have ads?

No, the Norwegian 4x4 Protocol app does not contain advertisements. It is free to download and use, with optional subscription plans for enhanced features.

### What devices does Norwegian 4x4 Protocol support?

Norwegian 4x4 Protocol is available on Apple Watch, iPhone, and iPad, offering a seamless experience across your Apple devices.

### How does Norwegian 4x4 Protocol help with VO2 max?

The app implements the Norwegian 4x4 interval training method, which is scientifically proven to be effective for increasing VO2 max. This protocol involves high-intensity intervals followed by recovery periods.

### Can I track my heart rate with Norwegian 4x4 Protocol?

Yes, you can connect your Apple Watch to the Norwegian 4x4 Protocol app to track your heart rate, heart rate zones, and calories burned during your workouts.

### What are the subscription options for Norwegian 4x4 Protocol?

Norwegian 4x4 Protocol offers a Pro subscription at $8.99 per week with a 3-day free trial, or $24.99 per year. These plans likely unlock additional features or content beyond the free version.

### How often is Norwegian 4x4 Protocol updated?

The app was last updated on March 7, 2026, to version 1.2.4. This indicates a relatively recent update, suggesting ongoing development and support for the application.

### Is Norwegian 4x4 Protocol suitable for beginners?

Yes, the app makes it easy to get started with the Norwegian 4x4 protocol by handling the timing of intervals. However, it's always recommended to consult a healthcare provider before starting any new exercise program.

## Version history (last 5 releases)

### 1.4.4 — 2026-08-15

Improvements and bug fixes

### 1.4.3 — 2026-07-21

Improvements and bug fixes

### 1.4.2 — 2026-07-06

Improvements and bug fixes

### 1.4.1 — 2026-06-15

• Made it possible to see the heart rate graph during a workout.
• You can now select even shorter work intervals.
• Workouts can now be saved without an Apple Watch.
• Fixed a problem where voice prompts might not play in the background.

### 1.4.0 — 2026-06-13

• Made it possible to see the heart rate graph during a workout.
• You can now select even shorter work intervals.
• Workouts can now be saved without an Apple Watch.
• Fixed a problem where voice prompts might not play in the background.

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## More apps by Havard Tryman

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All apps by Havard Tryman: https://appshunter.io/developer/1662964293

## Related topics

[norwegian 4x4 protocol](https://appshunter.io/ios/topics/norwegian-4x4-protocol) · [norwegian 4x4](https://appshunter.io/ios/topics/norwegian-4x4) · [norwegian 4x4 workout](https://appshunter.io/ios/topics/norwegian-4x4-workout) · [norwegian 4x4 timer](https://appshunter.io/ios/topics/norwegian-4x4-timer) · [norwegian 4x4 heart rate](https://appshunter.io/ios/topics/norwegian-4x4-heart-rate) · [norwegian 4x4 coach](https://appshunter.io/ios/topics/norwegian-4x4-coach)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-31.*