
Categories / HIIT & conditioning
Norwegian 4x4
Four 4-minute hard efforts with 3-minute recoveries.
How to start
After a 10-minute warm-up, do 4 intervals of 4 minutes at a hard effort (about 85 to 95% of maximum heart rate) with 3 minutes easy between, then cool down.
How to progress
Start with 2 or 3 intervals, and build to 4. Do it once or twice a week.
What the evidence says
Evidence: limited
We found no trials of this particular format. A 2026 analysis of the Generation 100 study (500 people aged 70 to 77) found that those who kept up high-intensity training had the smallest declines in fitness over 5 years. It was an observational analysis within a trial and does not prove the intervals were the cause.
Take care: Four minutes at high effort is demanding. See a GP first if you have a heart or blood pressure condition. Avoid it when unwell.
Sources
12-week starter plan
Once or twice a week. Use a heart rate monitor or the talk test: you should be able to say only a few words.
Tick each week as you finish it; your ticks are saved on this device only. Repeat a week if it felt hard. Weeks 4, 8 and 12 hold steady so you can settle. This is a general plan, not medical advice.
Add reminders to your calendar
Pick your days and time. You will download a calendar file that adds 12 weeks of reminders to Google, Apple or Outlook calendar.
Calories and weekly minutes
Enter your details for a rough estimate. Based on about 8 METs (Typical effort for this activity (estimated)). Real figures vary by 20% or more between people.
Tips and common mistakes
Tips
- Use a hill, bike or treadmill with a steady incline.
- Hard but controlled.
- Eat and drink before.
Common mistakes
- Starting too fast.
- Not warming up.
- Doing too many sessions.
Kit and cost
Low Approximate UK prices.
- A heart rate monitor (optional)
- A bike, treadmill or hill
- Trainers
Frequently asked questions
What is 4x4?
Four intervals of four minutes hard, with three minutes easy between.
Is it good for older adults?
One analysis suggests high-intensity training helps maintain fitness, but check with a GP first.
How often?
One or two sessions a week.
Good for: Heart & fitness Endurance
Compare with similar options
| Norwegian 4x4 | HIIT | Tabata | Sprint Interval Training | |
|---|---|---|---|---|
| Typical session | 40 min × 2/wk | 25 min × 3/wk | 4 min × 4/wk | 15 min × 3/wk |
| Effort | ●●●●● | ●●●●● | ●●●●● | ●●●●● |
| Cost | Low cost | Free | Free | Low cost |
| Equipment | Basic kit | No equipment | No equipment | Some equipment |
| Impact | Medium impact | Medium impact | Medium impact | Medium impact |
| Fitness needed | Moderate fitness | Some fitness | Moderate fitness | Moderate fitness |
| Evidence | limited | moderate | limited | moderate |