The Norwegian 4×4 workout, for runners

What is the Norwegian 4×4 workout?

It is a fixed interval session: a 10-minute warm-up at 60 to 70% of maximum heart rate, four 4-minute intervals at 85 to 95%, 3-minute active breaks at 60 to 70% between them, and a 5-minute cool-down. The aim is several minutes per rep near the top of your aerobic capacity.

That is the version published by the Cardiac Exercise Research Group (CERG) at NTNU in Trondheim (CERG exercise advice), which has studied it in heart patients, healthy adults and older people. Runners know it as a VO2 max session.

1. 01

   Warm up, 10 minutes

   Easy running at 60 to 70% of maximum heart rate, with optional short pickups at the end.

2. 02

   Interval 1 to 4, 4 minutes each

   Hard, at 85 to 95% of maximum heart rate. A few words, not sentences.

3. 03

   Active break, 3 minutes

   Easy jogging or brisk walking at 60 to 70%. Keep moving.

4. 04

   Cool down, 5 minutes

   Easy running or walking until your breathing settles.

Why four minutes on and three minutes off?

Because oxygen uptake and heart rate take a minute or two to climb at the start of a hard effort. A 4-minute rep leaves two or three minutes near the top of your aerobic range. A 3-minute easy break recovers you enough to start the next rep well, but not enough to cool off.

Four reps give about ten minutes of high-intensity time in forty, a dose most trained runners can repeat weekly without eating into the rest of their training. Shorter reps, like 15 seconds on and 15 off, reach the same heart rates across many more transitions; longer ones, like 8 minutes, run slower for more total time working hard.

Does the Norwegian 4×4 improve VO2 max?

In the best-known trial, yes, more than steady running did. VO2 max is the most oxygen your body can take up and use. Over eight weeks with total work matched, both interval groups of moderately trained men improved it significantly more than easy or threshold running. The 4×4 group gained 7.2%.

Stroke volume, the blood pumped per beat, rose about 10% after interval training. Helgerud and colleagues (2007) is small and in men only, and the 4×4 group started lower than the 15/15 group, with more room to improve. Its strength is the design: matched work, four groups, a clear result. Bacon and colleagues (2013) point the same way: across 37 interval-training studies, VO2 max rose an average 0.51 L/min over 6 to 13 weeks.

The protocol has clinical roots. In Wisløff and colleagues (2007), 27 patients with stable heart failure after a heart attack trained three times a week for 12 weeks: VO2peak rose 46% with intervals at 95% of peak heart rate, against 14% with moderate continuous training. In 21 patients with stable coronary disease, Rognmo and colleagues (2004) found treadmill intervals at 80 to 90% of VO2peak raised it 17.9%, against 7.9% at moderate intensity. Both were supervised hospital programs: proof the format can be dosed carefully, not a reason to try it unsupervised with a heart condition.

Is 4 × 4 minutes the best interval length?

Not necessarily. When trained cyclists did 4 × 4, 4 × 8 or 4 × 16 minutes for seven weeks, the 4 × 8 group, working slightly easier, gained about twice as much. Total time working hard seems to matter alongside intensity. The 4×4 is a strong, simple format, not the last word.

In the authors’ words, "32 min of work at 90% HR max induces greater adaptive gains than accumulating 16 min of work at ~95% HR max" (Seiler and colleagues, 2013). These were cyclists, over only seven weeks. Keep the 4×4, but a slightly controlled hard effort held for more total minutes may serve you as well as a near-maximal one. Pooled trials agree: intervals beat continuous training for VO2 max only by a possibly small margin (Milanović and colleagues, 2015).

Does the 4×4 help you live longer?

Not measurably over five years, in the best test so far. The Generation 100 trial randomized 1,567 Norwegians aged 70 to 77 to interval training, moderate continuous training or the national activity guidelines, and found no significant effect on all-cause mortality, with a lower trend after interval training.

In Stensvold and colleagues (2020), five-year mortality was 4.7% for control, 5.9% for moderate and 3.0% for intervals. The hazard ratio, intervals against control, was 0.63 (confidence interval 0.33 to 1.20, which includes no effect). Sessions were a 10-minute warm-up and 4 × 4 minutes at about 90% of peak heart rate. Honest summary: a survival benefit is possible but not shown.

How often should you do the Norwegian 4×4?

Once a week for most runners, twice at most, never on consecutive days and never in place of easy running. Run it after an easy or rest day, keep the next day easy, and keep it two or more days from your long run.

• Pace the first rep. Run the fourth at the first one’s pace. If rep four falls apart, rep one was too fast. It usually was.
• Run the first minute by effort. Heart rate takes a minute or two to climb, so don’t chase it; settle into a pace you can hold for all four minutes.
• Keep the breaks active. Easy jogging or brisk walking keeps blood moving and smooths the next rep.
• Use a hill or a treadmill for control. A gentle, steady incline reaches high heart rate at a slower speed. Flat road is fine too.
• Build up to it. New to running? Run easy for a few months first, then start with three reps.

How does Gears coach a 4×4?

Find a run includes a Norwegian 4×4 among its classic sessions, with VO2 max: long intervals and VO2 max: short intervals among its training targets. The reps run in Hard (Gear 3), easier running around them. More on guided running workouts and Gears as a VO2 max training app.

• Hard is your own pace range, placed from your own running and refined by every run with heart rate. The rep is coached by pace, so heart rate’s early lag doesn’t pull you off it.
• Countdowns and previews. The coach previews each change, counts down at 30 and 10 seconds and 3-2-1, and calls each rep by number.
• Safety always sounds. If heart rate goes very high, the coach tells you to ease off, at every toughness level and in Quiet.
• The plan keeps it rare. A Gears plan has at most two hard runs a week, never back to back.

What Gears doesn’t do: coach the 4×4 by a percentage of your maximum heart rate, measure your VO2 max, or promise what the session will change.