‘If you’re looking for a workout that delivers serious results in minimal time, the Norwegian 4x4 could be your next fitness obsession’ — a master trainer shares how to boost your cardiovascular fitness with this simple technique

Here on the Tom’s Guide fitness desk, we love nothing more than a weird and wonderful fitness trend — from the Japanese walking method to Jeffing, we’ve tried them all. This year, I’m training for my sixth marathon, and my first marathon since giving birth to my son two years ago. One science-backed method I’ve heard of when it comes to getting fitter, faster, is the Norwegian 4x4 method, so I spoke to Andy Carr, Master Trainer and Head of Fitness, Snap Fitness UK, to find out more about this approach to training.

Created by the Cardiac Exercise Research Group at the Norwegian University of Science and Technology (NTNU), the 4x4 method is a high-intensity interval training (HIIT) session that can be applied to all of your workouts. “The beauty of the Norwegian 4x4 lies in its adaptability. It can be applied to running, cycling, swimming, rowing, or even traditional gym cardio,” says Carr.

As always, if you’re recovering from an injury, you’re pregnant or postpartum, chat with a qualified expert before trying anything new.

What is the Norwegian 4x4 workout?

The Norwegian 4x4 workout consists of four-minute bursts of high-intensity activity, followed by three minutes of rest, repeated four times in total. The entire workout should take you around 40 minutes in total.

The key to this training is completing the high-intensity part of the exercise at 85-95% of your maximum heart rate. To calculate your maximum heart rate, subtract your age from 220 — for example, I am 33, so my maximum heart rate is 187 beats per minute (bpm). That means for this workout, my heart rate should sit between 158-177 bpm. The easiest way to keep an eye on your heart rate during a workout is to wear one of the best fitness trackers.

The workout is as follows:

• Warm-up: 5 to 10 minutes of light activity, such as brisk walking, cycling, or jogging.
• Intervals: For four minutes, run at 85 to 95% of your maximum heart rate. It should feel difficult and tough to speak in full sentences by the end of the first minute.
• Active Recovery: For three minutes, work on bringing your heart rate down to 60 - 70% of your maximum heart rate by turning your run into a slow jog or a walk.
• Repeat: Repeat the above intervals and active recovery instructions for four rounds in total.
• Cool down: 5 to 10 minutes of slow walking, followed by some light stretches.

What are the benefits?

“The headline benefit of the Norwegian 4x4 is its proven ability to boost VO2 Max, the measure of how efficiently your body uses oxygen during exercise,” explains Carr. “A higher VO2 Max not only enhances performance but is also linked to a longer, healthier life.”

If you’re short on time, this is a workout to try. “It’s time-efficient, burns calories fast, and fits around busy schedules,” says Carr. “Aim to do the workout twice a week for the best results, or even once as part of your broader routine for noticeable cardiovascular gains.”

Avoid doing this workout more than twice a week, and ensure you’re giving your body time to recover between sessions. “As with any high-intensity training, recovery is key. Overexertion and muscle strain are real risks if you push too hard or skip warm-ups and cooldowns. Listen to your body and remember that rest days are part of the process,” says Carr.

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