# Norwegian 4x4 Heart Rate — VO2max interval timer with HR

> VO2max interval timer with Bluetooth HR monitoring for aerobic training. (iPhone/iPad app by Abe Stanway.)

- Source: https://appshunter.io/ios/app/norwegian-4x4-heart-rate/id6770760726 (this page in markdown: same URL + `.md`)
- Developer: [Abe Stanway](https://appshunter.io/developer/1896762902)
- Category: Health & Fitness
- Price: Free
- Rating: 5.00/5 from 1 App Store ratings
- Age rating: 4+
- Requires: iOS 17.0 · 1 MB
- Languages: American English
- Released: 2026-05-21
- Data updated: 2026-07-06
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/norwegian-4x4-heart-rate/id6770760726/reviews.md

## What is Norwegian 4x4 Heart Rate?

Norwegian 4×4 is the Helgerud VO2max interval protocol, built for athletes who want to push their aerobic ceiling.

Connect any Bluetooth heart-rate monitor — Whoop broadcast, Polar H10, Wahoo TICKR, Garmin HRM, or any device exposing the standard heart-rate service — and the app guides you through a 5 min warm-up, 4 × (4 min hard / 3 min easy), and 5 min cool-down.

A live heart-rate gauge shows when you're in the target zone (85–95% HRmax during work intervals, 60–70% during rest). The app speaks "Speed up" or "Slow down" until you hit the zone. Audio cues mark each phase transition; a 9-second countdown gives you time to start working out.

All data stays on your phone. No accounts, no analytics, no servers.

## Key features

- Bluetooth heart rate monitor support
- VO2max interval protocol guidance
- Live heart rate gauge
- Audio cues for speed adjustments
- Phase transition audio cues
- On-device data storage


## Frequently asked questions about Norwegian 4x4 Heart Rate

### What is the Norwegian 4x4 Heart Rate app?

Norwegian 4x4 Heart Rate is a free app designed to guide users through the Helgerud VO2max interval protocol. It uses a connected Bluetooth heart rate monitor to provide real-time feedback and audio cues.

### What heart rate monitors are compatible with Norwegian 4x4 Heart Rate?

The app supports any Bluetooth heart rate monitor that exposes the standard heart-rate service. This includes popular brands like Whoop, Polar H10, Wahoo TICKR, and Garmin HRM.

### How does Norwegian 4x4 Heart Rate guide my workout?

The app guides you through a 5-minute warm-up, four 4-minute hard intervals with 3-minute easy intervals, and a 5-minute cool-down. It provides live audio cues to speed up or slow down to stay within target heart rate zones.

### Does Norwegian 4x4 Heart Rate collect my data?

No, all your workout data stays on your phone. The app does not require accounts, collect analytics, or use servers, ensuring your privacy.

### What is the target heart rate zone for Norwegian 4x4 Heart Rate?

During the hard work intervals, the target zone is 85–95% of your HRmax. During the easy rest intervals, the target zone is 60–70% of your HRmax.

### How often is Norwegian 4x4 Heart Rate updated?

The latest version, 1.1, was released on May 22, 2026, indicating recent development activity. The app was initially released on May 21, 2026.

### What devices does Norwegian 4x4 Heart Rate support?

Norwegian 4x4 Heart Rate is currently supported on iPhones. It has an age rating of 4+.

### Does Norwegian 4x4 Heart Rate have ads?

No, Norwegian 4x4 Heart Rate is ad-free. It is a completely free application with no advertisements.

## Version history (last 2 releases)

### 1.1 — 2026-05-22

Added Live Activities on lock screen

### 1.0 — 2026-05-21

No release notes.

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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 2026-07-06.*