Norwegian 4×4
Norwegian 4×4 workout builder
Four hard 4-minute intervals with 3 minutes of easier movement between them. Enter your age or max heart rate and your sport, and get your target heart rates, a printable workout card and a timer. Works on a bike, rowing machine, steep walk or run.
Enter your age (or your own max heart rate) to see your target heart rates.
4×4 interval timer
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My training log
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The Norwegian 4×4 protocol
| Part | Time | Intensity | Source |
|---|---|---|---|
| Warm-up | about 10 min | easy to moderate | our suggestion |
| Interval × 4 | 4 min each | 90–95% of max heart rate | Helgerud 2007 |
| Active rest × 3 | 3 min each | about 70% of max heart rate | Helgerud 2007 |
| Cool-down | about 5 min | easy | our suggestion |
“Active rest” means you keep moving slowly instead of stopping. 90–95% feels hard: you can say a few words but not hold a conversation. Heart rate rises during each interval, so you often reach the target only in the second half of the 4 minutes.
No max heart rate? We estimate it with Tanaka (208 − 0.7 × age) or, for women who choose it, Gulati (206 − 0.88 × age). Both are averages, and your own max can be quite different. See max heart rate by age.
What the research shows
- Helgerud 2007 (NTNU, Norway): 40 healthy, non-smoking, moderately trained young men were split into four groups. All trained 3 times a week for 8 weeks with the same total work. VO₂ max rose 7.2% with 4×4 (55.5 → 60.4 ml/kg/min) and 5.5% with 15/15 (60.5 → 64.4). Both interval groups improved significantly more than the groups training at 70% or 85% of max heart rate. The study only included young men who ran, so results for women, older people and other sports may differ.
- Generation 100 (Stensvold 2020): 1,567 healthy adults aged 70–77 in Trondheim were followed for five years. One group did interval sessions at about 90% of peak heart rate twice a week. 3.0% of that group passed away during the study, compared with 4.7% of the group following the national activity advice. The difference was not statistically certain (hazard ratio 0.63, 95% CI 0.33–1.20), and the training groups combined did no better than the advice group. What it does show: healthy people in their 70s carried out this kind of training for years.
4×4 on a bike, rower, walk or run
| Sport | Hard 4 minutes | Active rest |
|---|---|---|
| Bike | Raise resistance or gear until breathing is heavy; keep a steady cadence. | Easy gear, keep pedalling. |
| Rowing machine | Long, strong strokes at a higher stroke rate. | Row light and relaxed. |
| Incline walking | Fast walk up a steep treadmill incline or hill. | Flatten the incline or walk back down. |
| Running | Hard but controlled; uphill is easier on the legs. | Jog or walk slowly. |
The study used running. Using the same heart-rate targets on other machines is our adaptation. Running plans are on runperform.com; easy zone 2 sessions on zone2cardio.app.
15/15 intervals
The other interval group in Helgerud 2007 did 15 seconds at 90–95% of max heart rate followed by 15 seconds of active rest at 70%, again 3 times a week for 8 weeks. VO₂ max rose 5.5% (60.5 → 64.4 ml/kg/min). Heart rate cannot settle in 15 seconds, so go by effort: hard for 15 seconds, easy for 15. Your 90–95% zone: enter your age above.
15/15 interval timer
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Make it a plan
Want week-by-week guidance? The 8-week VO₂ max training plan builds on the same study, with an easier start for beginners and people over 50. More ideas: how to improve VO₂ max · heart-rate zones · test your VO₂ max before and after.
FAQ
What is the Norwegian 4×4 workout?
Four intervals of 4 minutes at 90–95% of your max heart rate, with 3 minutes of active rest at about 70% between them. This is the 4×4 protocol tested by researchers at NTNU in Trondheim, Norway (Helgerud 2007).
How much did VO₂ max improve in the study?
In Helgerud 2007, 40 healthy, moderately trained young men trained 3 times a week for 8 weeks. The 4×4 group improved VO₂ max by 7.2% (from 55.5 to 60.4 ml/kg/min) and the 15/15 group by 5.5% (60.5 to 64.4). Both interval groups improved significantly more than groups doing the same total work at 70% or 85% of max heart rate. Results in other people, ages and sports can differ.
Can I do the 4×4 on a bike, rowing machine or by walking?
Yes, as long as you can push your heart rate to 90–95% of max. The 2007 study used running; using the same heart-rate targets on a bike, rower or steep incline walk is our adaptation. Your max heart rate can differ between sports, so use your own max for that sport if you know it.
How often should I do 4×4 intervals?
The 2007 study used 3 sessions a week for 8 weeks in young men. In Generation 100, healthy 70–77-year-olds did interval sessions at about 90% of peak heart rate twice a week. Our 8-week plan uses 1–3 interval days a week depending on your level and age.
Is the Norwegian 4×4 good for beginners?
It is hard. If you are new to hard training, start with 2 or 3 intervals instead of 4 (our easier start, not from the study) and build up over a few weeks. Talk to your doctor first if you have heart disease, high blood pressure, chest pain or dizziness.
Does 4×4 training help you live longer?
That is not proven. In Generation 100 (1,567 healthy adults aged 70–77, five years), 3.0% of the interval group passed away compared with 4.7% of the control group, but the difference was not statistically certain (hazard ratio 0.63, 95% CI 0.33–1.20).
Sources
- Helgerud J, Høydal K, Wang E, et al. Aerobic high-intensity intervals improve VO2max more than moderate training. Med Sci Sports Exerc 2007;39(4):665–671. doi:10.1249/mss.0b013e3180304570
- Stensvold D, Viken H, Steinshamn SL, et al. Effect of exercise training for five years on all cause mortality in older adults — the Generation 100 study: randomised controlled trial. BMJ 2020;371:m3485. doi:10.1136/bmj.m3485 (free: PMC7539760)
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol 2001;37(1):153–156. doi:10.1016/S0735-1097(00)01054-8
- Gulati M, Shaw LJ, Thisted RA, Black HR, Bairey Merz CN, Arnsdorf MF. Heart rate response to exercise stress testing in asymptomatic women: the St. James Women Take Heart Project. Circulation 2010;122(2):130–137. doi:10.1161/CIRCULATIONAHA.110.939249
Last updated: October 18, 2026. Written with AI assistance from the sources above. Not medically reviewed.