The Norwegian 4×4 workout: can this HIIT method improve fitness faster?

A shortage of time is frequently the biggest barrier to exercising consistently. However, an interval-training method recently highlighted by actress Jessica Biel may offer an answer. Research suggests it can boost fitness more quickly than conventional steady-state exercise, including jogging or cycling.

Known as the Norwegian 4×4 workout, this approach has long been used by athletes. It is a form of high-intensity interval training (HIIT), built around four-minute bouts of very demanding cardiovascular exercise, each followed by three minutes of very easy activity.

A standard session consists of a five-minute warm-up, four high-intensity intervals, and a five-minute cool-down.

How the Norwegian 4×4 workout works

Like other HIIT formats, the 4×4 workout alternates high-intensity effort with low-intensity activity or rest. Most HIIT sessions use work intervals ranging from ten seconds to a couple of minutes. The 4×4 workout, by comparison, uses four-minute work periods, keeping the heart rate elevated for longer than most HIIT protocols.

Decades of research indicate that regular HIIT sessions can be more effective than moderate-intensity exercise – such as continuous running or cycling at a steady pace – for improving cardiovascular fitness and other health measures, including blood sugar and cholesterol levels. HIIT can also improve health in adults with type 2 diabetes and cardiovascular disease.

It delivers these advantages in less training time than conventional endurance exercise. A 2008 study found that just six HIIT sessions across two weeks improved the endurance capacity of muscles.

A number of studies have examined the benefits of the 4×4 protocol specifically. For instance, one eight-week study found that the 4×4 workout improved aerobic fitness more than 45-minute sessions of moderate-intensity running.

The 4×4 workout is particularly effective for cardiovascular fitness because its four-minute intervals are hard enough to place maximum demands on the heart and lungs, while limiting muscle fatigue. This can increase maximum oxygen uptake, or VO₂ max: the greatest rate at which the body can absorb, transport and use oxygen during strenuous activity.

VO₂ max is regarded as the gold-standard measure of cardiovascular fitness. Greater VO₂ max values are linked with a lower risk of cardiovascular disease and premature death, as well as better general health.

In a 4×4 workout, you will spend approximately 16 minutes close to your maximum heart rate. As a result, it may raise VO₂ max more effectively than moderate-intensity sessions of a longer duration.

Choosing the right workout

For people with demanding schedules, HIIT is an efficient choice, providing the same health and fitness benefits as longer workouts in less time. Yet a 4×4 HIIT session still takes between 35–40 minutes, which may be longer than some people can manage.

For anyone wanting a briefer session, the 10×1 HIIT protocol is an appropriate alternative, as it takes only 30 minutes to complete, including the warm-up and cool-down.

This protocol involves ten intervals lasting one minute each at a high intensity. Every minute of hard effort is followed by one minute of gentle exercise or complete rest.

Although this format can also increase VO₂ max, its shorter work intervals need to be completed at a far higher intensity than the four-minute intervals in order to challenge the cardiovascular system. That may make maintaining a consistent pace through every interval more difficult.

Sprint interval training is another HIIT option. It requires exercising as hard as possible for ten to 20 seconds, before taking three minutes to recover. These sprints can be completed by running, cycling or rowing.

One 12-week study showed that participants who completed three 20-second sprints, each followed by three-minute recovery periods, only three times per week substantially improved their cardiovascular fitness compared with people doing longer steady-state exercise.

However, the 4×4 workout has been found to produce greater improvements in aerobic fitness than sprint interval training.

Enjoyment and consistency matter

While most research shows that HIIT can produce health and fitness improvements quickly, determining precisely how well it works in everyday life is difficult. Most studies use specialised equipment and researcher supervision, meaning their findings may not represent what occurs when people exercise independently.

HIIT's highly demanding nature can also make it less enjoyable for some people, especially those unfamiliar with intense exercise. This matters because enjoying exercise less is associated with weaker motivation and a reduced chance of maintaining a training programme.

Moreover, although HIIT is often marketed as exciting and time-efficient, the novelty can fade. What initially feels fresh and motivating may eventually become exhausting or monotonous, particularly when there is no variety or support. Consequently, some people may find it hard to continue a workout programme after several weeks.

Lasting improvements in fitness depend on exercising regularly. It is therefore vital to select a type of activity that you enjoy.

If HIIT appeals to you less than alternatives such as steady jogging, cycling or weightlifting, concentrating on exercise you are more likely to sustain may be more effective.

You do not need to exercise at maximum intensity every time to enhance your health and fitness. Regular activity alone, such as building up around 7,000 steps a day, can still provide meaningful benefits for physical and mental health.

The Norwegian 4×4 protocol is simply the latest HIIT workout to become popular. Although it can provide many fitness and health benefits in a short time, it may not meet your needs, so choose the workout that best fits your goals and schedule.

Paul Hough, Lecturer Sport & Exercise Physiology, University of Westminster

This article is republished from The Conversation under a Creative Commons licence. Read the original article.