Here at the Tom’s Guide fitness desk, we’re always drawn to unusual and innovative workout trends — from the Japanese walking method to Jeffing, we’ve tested them all. This year, I’m preparing for my sixth marathon and my first since giving birth to my son two years ago. While researching ways to improve fitness and speed, one science-backed approach kept coming up: the Norwegian 4×4 method. To understand it better, I spoke with Andy Carr, Master Trainer and Head of Fitness at Snap Fitness UK, for expert insight.
Developed by the Cardiac Exercise Research Group at the Norwegian University of Science and Technology (NTNU), the 4×4 method is a form of high-intensity interval training (HIIT) that can be adapted to almost any workout. “The strength of the Norwegian 4×4 lies in how versatile it is,” Carr explains. “It works just as well for running, cycling, swimming, rowing, or standard gym-based cardio.”
As with any new fitness routine, anyone recovering from injury, pregnant, or postpartum should consult a qualified professional before getting started.
Understanding the Norwegian 4×4 Workout Structure
The Norwegian 4×4 workout is built around four-minute intervals of high-intensity exercise, followed by three minutes of recovery, repeated four times. In total, the session lasts around 40 minutes.
The most important element is intensity. Each four-minute effort should be performed at 85–95% of your maximum heart rate. To estimate your maximum heart rate, subtract your age from 220. For example, at 33 years old, the estimated maximum heart rate is 187 beats per minute (bpm), making the target range for this workout 158–177 bpm. Using a fitness tracker is the simplest way to monitor heart rate during training.
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Step-by-Step Workout Breakdown
- Warm-up: 5–10 minutes of light movement such as brisk walking, cycling, or gentle jogging.
- High-intensity interval: Run for four minutes at 85–95% of your maximum heart rate. This should feel challenging, with talking becoming difficult within the first minute.
- Active recovery: Spend three minutes reducing your heart rate to 60–70% of its maximum by slowing to a jog or walk.
- Repeat: Complete the interval and recovery sequence for a total of four rounds.
- Cool down: Finish with 5–10 minutes of slow walking, followed by light stretching.
Key Benefits of the Norwegian 4×4 Method
“The standout advantage of the Norwegian 4×4 is its proven ability to increase VO2 max, which measures how efficiently your body uses oxygen during exercise,” says Carr. “Improving VO2 max not only enhances athletic performance but is also associated with a longer and healthier life.”
For those with limited time, this workout is particularly effective. “It’s time-efficient, helps burn calories quickly, and fits easily into busy schedules,” Carr adds. “For optimal results, aim to complete it twice per week, or even once weekly as part of a broader routine to see noticeable cardiovascular improvements.”
It’s important not to overdo it. Avoid performing this workout more than two times per week and allow sufficient recovery between sessions. “As with any high-intensity training, recovery is essential,” Carr warns. “Skipping warm-ups, cooldowns, or rest days increases the risk of overexertion and muscle strain. Pay attention to your body — rest is a vital part of progress.”
