About Us
Making science-backed interval training accessible to everyone — from elite athletes to first-time HIIT beginners.
Making science-backed interval training accessible to everyone — from elite athletes to first-time HIIT beginners.
with Dr. Rhonda Patrick, Ph.D.
The Norwegian 4x4 method was discussed as an evidence-based protocol for longevity and cardiovascular health — validating the research our app is built on.
We believe the world's most effective interval training protocol shouldn't be locked behind sports science journals or elite coaching programs. Our mission is to democratize the Norwegian 4x4 Protocol — bringing NTNU-backed HIIT training to anyone with a smartphone and 38 minutes to spare.
The Norwegian 4x4 Protocol App provides guided timers, heart rate zone tracking, audio cues, and educational resources so every user can train at the right intensity — whether they're preparing for a marathon or taking their first steps into HIIT.
The protocol is grounded in decades of Norwegian exercise science:
Developed and validated by researchers at the Norwegian University of Science and Technology, including pioneering VO₂ max studies.
Built on work by Jan Helgerud, Jan Hoff, and Ulrik Wisløff — leaders in interval training science.
Every feature in our app reflects peer-reviewed findings on heart rate zones, interval timing, and VO₂ max improvement.
Our articles and guides are written by the Norwegian 4x4 Protocol Team, reviewed against primary research sources.
Thousands of users across 30+ countries rely on the Norwegian 4x4 Protocol App for structured HIIT training. Rated 4.8 out of 5 on the App Store, our community spans elite endurance athletes, HYROX competitors, marathon runners, and beginners discovering interval training for the first time.
Want to understand the workout structure? Visit our homepage for the full 38-minute protocol breakdown, or explore our FAQ for training frequency, heart rate zones, and nutrition guidance.
Get guided 38-minute workouts with heart rate tracking on iOS and Android.
Download NowSubscribe for training tips, protocol updates, and HIIT research highlights.
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