# Crescendo 4x4: Norwegian HIIT

> VO2 max interval timer, 30 sec

Canonical page: [https://chrome-stats.com/d/id6791945508](https://chrome-stats.com/d/id6791945508)

## Overview

- **ID:** `id6791945508`
- **Platform:** Apple
- **Type:** Apple app
- **Status:** Available
- **Publisher:** KRZYSZTOF ANDRZEJ OTRZASEK
- **Category:** Health & Fitness
- **Version:** 1.3
- **Last updated:** 2026-09-03
- **First published:** 2026-08-09
- **Size:** 2.85 MB
- **Data as of:** 2026-09-21
- **Store listing:** [Apple App Store](https://apps.apple.com/us/app/crescendo-4x4-norwegian-hiit/id6791945508)
- **Website:** [https://mistylogic.com/crescendo4x4/guides](https://mistylogic.com/crescendo4x4/guides)
- **Privacy policy:** [https://mistylogic.com/crescendo4x4/privacy](https://mistylogic.com/crescendo4x4/privacy)

## Description

The Norwegian 4×4 protocol builds VO₂max like almost nothing else — four 4-minute pushes at 85–95% of max heart rate. The problem? Starting there feels like hitting a wall.

Crescendo removes the wall. You start with intervals as short as 30 seconds and climb a structured on-ramp, level by level, until the full 4×4 is yours. Progress is earned, never rushed — the app can even gently hold a level-up if your recovery data suggests you need it.

GUIDED SESSIONS
• Voice cues for every phase — works with the screen locked, music keeps playing
• Warm-up, four work/recovery cycles, cool-down: fully guided
• Date-anchored timing that never drifts

PERSONAL BY DESIGN
• Heart-rate zones from your real max HR — from Apple Health or set manually
• A conservative level-up gate that watches your resting HR and VO₂max trends
• Start where YOU are: from 30-second familiarization runs to the full protocol

APPLE WATCH + HEALTH
• Send any session to your Watch and run it from the native Workout app
• Watch-run sessions count toward your progress automatically
• Phone sessions save to Apple Health (your choice)

HONEST BY DEFAULT
• No account. No ads. No streak guilt.
• Your health data stays in Apple Health — we don't collect it.

High-intensity interval training is demanding. If you're unsure about your health, check with your doctor before starting.

## Rankings

- #1,129,972 — Overall

## Similar extensions and apps

- [VO2 Flow: Norwegian 4x4 Timer](https://chrome-stats.com/d/id6757104585) — 5.00 / 5
- [Four by Four (fa7b3d)](https://chrome-stats.com/d/id6766068267)
- [Norwegian 4x4 Protocol](https://chrome-stats.com/d/id6499464775) — 4.30 / 5
- [Ramp4x4: VO2 Max Trainer](https://chrome-stats.com/d/id6768789400)
- [Peak Intervals](https://chrome-stats.com/d/id6757667069)
- [4x4 HIIT](https://chrome-stats.com/d/id6755360081)
- [Norwegian 4x4 HIIT - Myworkout](https://chrome-stats.com/d/id6497329690) — 4.70 / 5
- [Norwegian 4x4 Protocol: Boreas](https://chrome-stats.com/d/id6751464534) — 4.80 / 5
- [Norwegian 4x4 Coach](https://chrome-stats.com/d/id6782398289) — 5.00 / 5
- [Norwegian 4x4 Heart Rate](https://chrome-stats.com/d/id6770760726) — 5.00 / 5
- [N4x4](https://chrome-stats.com/d/id6686407796) — 4.40 / 5
- [Boost VO2 - Norwegian 4x4](https://chrome-stats.com/d/id6748565289) — 4.00 / 5

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Source: [Chrome-Stats](https://chrome-stats.com/d/id6791945508)