The Norwegian 4×4 workout, a form of high-intensity interval training (Hiit), is drawing attention for its proven ability to improve fitness more efficiently than steady-paced workouts like jogging or cycling. This specific workout format is supported by decades of research, with multiple studies showing that it can significantly boost aerobic capacity, cardiovascular health, and metabolic function, even in people with chronic conditions. Its structure is simple, but the results are consistently measurable.
Time constraints remain one of the main reasons people avoid regular exercise. Hiit has grown in popularity for its time-efficient benefits, offering similar, or better, health outcomes compared to traditional endurance training, but in shorter sessions. Among these routines, the 4×4 format stands out because of its longer work intervals and balanced recovery periods, providing a sustained cardiovascular challenge while minimizing muscle fatigue.
The method, long used by athletes in Norway, is now promoted as a practical option for everyday exercisers, especially those looking for serious results in less time.
Longer Intervals, Deeper Impact
The Norwegian 4×4 workout is a structured Hiit session that consists of a five-minute warm-up, followed by four intervals of four minutes of intense cardio exercise. Each high-intensity round is separated by three minutes of light activity, and the session ends with a five-minute cool-down. Unlike most Hiit formats, which include brief intervals of 10 seconds to 2 minutes, the 4×4 protocol extends each interval to four minutes, keeping the heart rate high for longer and pushing cardiovascular limits.
Increase Your VO2 Max by 13%
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This format is particularly effective at raising VO₂ max, the maximum rate at which the body can take in and use oxygen during intense exercise. As reported by ScienceAlert, VO₂ max is widely recognized as the gold standard for cardiovascular fitness, with higher values linked to reduced risk of heart disease, lower premature death rates, and better overall health.
An eight-week study mentioned in the article compared the 4×4 method to 45-minute moderate-intensity running sessions, revealing that those who followed the 4×4 protocol saw greater improvements in aerobic fitness. The longer interval length is a key factor, it challenges the heart and lungs without overloading the muscles, allowing for intense cardiovascular work while managing fatigue.
More Gains in Less Time
Years of research support the claim that Hiit offers faster and more powerful fitness improvements than continuous moderate-intensity exercise. According to a 2008 study, even six Hiit sessions over two weeks were enough to enhance muscle endurance capacity.
The 4×4 protocol, in particular, delivers meaningful results with fewer total minutes spent training. A full session lasts 35 to 40 minutes, including warm-up and cool-down, but participants spend roughly 16 minutes working near their maximum heart rate, a level of intensity that efficiently boosts VO₂ max and cardiovascular performance.
Hiit has also been shown to benefit adults with type 2 diabetes and cardiovascular disease, improving key health metrics like blood sugar regulation and cholesterol levels. These benefits come with less overall training time, making routines like the 4×4 both practical and effective for a wide range of individuals.
Not for Everyone, but Worth Trying
While the 4×4 format offers impressive outcomes, it may not be suitable for everyone. For some, even a 40-minute session might feel too long or demanding. Alternatives like the 10×1 protocol, which involves ten one-minute high-intensity intervals, each followed by a minute of rest or light activity, can be completed in about 30 minutes and also improve VO₂ max. But shorter intervals must be performed at a higher intensity to achieve similar cardiovascular stress, which can make it harder to pace and maintain consistency.
Another option is sprint interval training, which consists of 10- to 20-second all-out efforts followed by three-minute recovery periods. These can be done through running, cycling, or rowing. One 12-week study found that doing three 20-second sprints with recovery, three times a week, significantly boosted cardiovascular fitness compared to longer, steady-state routines. Still, 4×4 training has shown greater gains in aerobic fitness than sprint-based Hiit models.
There are also questions about how effective these programs are outside of supervised settings. Many of the studies use controlled environments and equipment, making it unclear how results would translate to unsupervised, real-world workouts. Furthermore, the intensity of Hiit may limit its appeal; people who find the workouts too physically or mentally demanding may struggle to stick with them over time.
Enjoyment and consistency play a big role in long-term success. While Hiit can deliver fast results, its novelty can fade, and repetition without variation or support can make it feel monotonous. As Paul Hough, lecturer in sport and exercise physiology at the University of Westminster, points out, consistent activity, whether it’s Hiit, steady jogging, cycling, or strength training, is key to sustainable progress. Even low-impact habits, like walking around 7,000 steps a day, can produce meaningful physical and mental health gains.