# Z2/4×4 Trainer

> Zone 2 & 4×4 cardio coach

Canonical page: [https://chrome-stats.com/d/id6776864990](https://chrome-stats.com/d/id6776864990)

## Overview

- **ID:** `id6776864990`
- **Platform:** Apple
- **Type:** Apple app
- **Status:** Available
- **Publisher:** Chenfei Chu
- **Category:** Health & Fitness
- **Version:** 1.0.2
- **Last updated:** 2026-07-26
- **First published:** 2026-07-07
- **Size:** 5.21 MB
- **Data as of:** 2026-09-22
- **Store listing:** [Apple App Store](https://apps.apple.com/ca/app/z2-4-4-trainer/id6776864990)
- **Website:** [https://logolo.ca/z24x4](https://logolo.ca/z24x4)
- **Privacy policy:** [https://ozzyfly.github.io/z2-4x4-trainer/privacy-policy.html](https://ozzyfly.github.io/z2-4x4-trainer/privacy-policy.html)

## Description

Z2/4×4 Trainer turns the two most effective endurance methods — easy Zone 2 base work and high-intensity Norwegian 4×4 intervals — into a simple daily plan built around YOUR heart rate.

WHAT YOU GET
• Daily and weekly Zone 2 prescriptions at 60–70% of your max heart rate to build your aerobic base.
• Norwegian 4×4 sessions: four 4-minute intervals at 85–95% of max heart rate, with 3-minute recoveries — the protocol used to boost VO2 max.
• Weekly health-maintenance and weight-loss targets to keep you consistent.
• Personalized zones from your max heart rate (220 − age), which you can override if you know your true max.

WORKS WITH APPLE HEALTH
• Pull in your heart rate, resting heart rate, active energy, body weight, and past workouts — or enter everything manually. Your choice.
• Completed Zone 2 and 4×4 workouts are saved back to Apple Health so all your training lives in one place.

IPHONE + APPLE WATCH
• Plan and review on iPhone; train with your zones on your wrist.

PRIVATE BY DESIGN
• 100% on-device. No account, no sign-up, no server.
• Nothing you enter or that we read from Apple Health ever leaves your device.
• No ads, no analytics, no tracking, no third-party SDKs.
• Your Health data is never used for advertising — ever.

WHO IT'S FOR
• Runners, cyclists, rowers, and anyone doing cardio who wants structure instead of guesswork.
• Beginners building a base and experienced athletes adding VO2-max work.

FREE + AN OPTIONAL ONE-TIME UPGRADE
• Everything above is free: guided workouts on iPhone and Apple Watch, plans, zones, Apple Health sync.
• One optional one-time purchase (Pro) unlocks the deeper coaching analysis: full readiness breakdown, overtraining guard, adaptive weekly progression, VO2-max trend, and CSV/JSON export. No subscription.

Z2/4×4 Trainer is a fitness and training tool, not a medical device. It does not diagnose, treat, or prevent any disease. Talk to a healthcare professional before starting a new exercise program.

## Rankings

- #1,804,392 — Overall

## Similar extensions and apps

- [Heart Rate Zones Trainer](https://chrome-stats.com/d/id6772269496)
- [Norwegian 4x4 Coach](https://chrome-stats.com/d/id6782398289) — 5.00 / 5
- [Zone2 Fitness](https://chrome-stats.com/d/id6444166065) — 3.70 / 5
- [Peak Intervals](https://chrome-stats.com/d/id6757667069)
- [Zone 2 Training Coach](https://chrome-stats.com/d/id6762536918)
- [Zone2Track](https://chrome-stats.com/d/id6451061206) — 4.40 / 5
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- [Zone Training Log](https://chrome-stats.com/d/id6757948716)
- [Ramp4x4: VO2 Max Trainer](https://chrome-stats.com/d/id6768789400)
- [Simple Zones](https://chrome-stats.com/d/id1533922808) — 4.00 / 5
- [4x4 Treadmill](https://chrome-stats.com/d/id6758803671)
- [RunBeat: Zone 2 & Intervals](https://chrome-stats.com/d/id6760047155) — 4.90 / 5

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Source: [Chrome-Stats](https://chrome-stats.com/d/id6776864990)