Norwegian 4x4 Protocol: Boreas

Norwegian 4x4 Protocol: Boreas

Interval training for VO2 max

49 ratings
5 reviews
Free
In-App Purchases

Details

  • Released
  • Updated

Features

Norwegian 4x4 Protocol: Boreas screenshot #1 for iPhone
Norwegian 4x4 Protocol: Boreas screenshot #2 for iPhone
Norwegian 4x4 Protocol: Boreas screenshot #3 for iPhone
Norwegian 4x4 Protocol: Boreas screenshot #4 for iPhone
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About

This app guides you through the Norwegian 4x4 interval training protocol to improve your VO2 max and cardiovascular fitness. It offers customizable warm-up and cooldown durations, voice guidance for intervals, and integrates with Apple Watch for heart rate and calorie tracking.

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

1.4.2

July 6, 2026

Improvements and bug fixes

Subscription plans

Pro

Unlock Pro features

$24.991 Year
How to cancel Norwegian 4x4 Protocol subscription ⁉️

User reviews

Best Norwegian 4x4 app with incredible dev support!

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!

Response from developer

Thank you for the review!

It finally works!

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

Response from developer

Thanks for the review!

Good Workout Companion

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.
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No heart guidance??

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.
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Response from developer

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.

Good Workout Companion

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.
Show more

Developer apps

FAQ

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.