VO2 Flow: Norwegian 4x4 Timer
Norwegian 4x4 Interval Trainer
About
This interval training app guides you through the Norwegian 4x4 protocol or allows you to create custom workout routines. It offers audio cues, haptic feedback, and music integration to enhance your training sessions. Track your progress with workout history and unlock achievements.
What's New in VO2 Flow
2.6.1
June 14, 2026
Your full workout history is now available to everyone, free. Plus minor stability improvements.
Subscriptions & In-App Purchases
$4.99
Pro Upgrade
Unlimited profiles, no ads Workout history, badges
Developer apps
FAQ
What is the Norwegian 4x4 protocol in VO2 Flow?
The Norwegian 4x4 protocol involves four 4-minute intervals at 90-95% of your maximum heart rate, with 3-minute recovery periods between each interval. VO2 Flow has this protocol built-in and ready to start.
Can I create my own workout routines in VO2 Flow?
Yes, VO2 Flow allows you to build your own custom interval profiles. You can set any work and rest combination and any number of rounds, in addition to pre-set protocols like Tabata.
Does VO2 Flow have ads?
VO2 Flow contains advertisements. You can remove all ads forever with a one-time Pro upgrade purchase of $4.99.
What are the benefits of the Pro upgrade in VO2 Flow?
The Pro upgrade, a $4.99 one-time purchase, removes all ads, unlocks unlimited custom interval profiles, and grants access to achievement badges. Future Pro features will also be included without a subscription.
How does VO2 Flow track my workouts?
VO2 Flow logs every completed session in your workout history, grouping them by month. This allows you to review your progress and completed workouts over time.
What devices is VO2 Flow compatible with?
VO2 Flow is available for iPhone, iPad, and iPod. It supports both landscape and portrait orientations.
How often is VO2 Flow updated?
The latest version of VO2 Flow is 2.6.1, last updated on June 14, 2026. This indicates regular updates to improve functionality and add features.
What is the age rating for VO2 Flow?
VO2 Flow has an age rating of 4+, making it suitable for a wide range of users interested in fitness tracking.
