Norwegian 4x4 vs Zone 2 for Longevity
Polarized training—Zone 2 volume plus 4x4 HIIT for longevity.
Zone 2 Heart Rate Calculator
Find your Zone 2 range three ways, see all five training zones, and the heart rates for Norwegian 4x4 intervals.
Enter your age. Add your resting heart rate for the more personal heart-rate reserve method.
An estimate for training, not a medical diagnosis. Talk to your doctor before starting hard exercise if you have a heart condition, high blood pressure, take heart medication, or have symptoms when you exert yourself.
What Zone 2 is, and how it fits with the Norwegian 4x4
Zone 2 is the easy end of endurance training: about 60–70% of your maximum heart rate, an effort you could hold for an hour while talking in full sentences. It trains the slow-twitch muscle fibres and mitochondria that burn fat, improves how well your heart fills with blood, and helps you recover between hard days.
The Norwegian 4x4 is the opposite end: four 4-minute intervals at 85–95% of max heart rate. The two work best together. A typical week has 1–2 Norwegian 4x4 sessions to raise VO2 max and 2 Zone 2 sessions to build the base underneath it. Read Norwegian 4x4 vs Zone 2 for longevity for the research on each.
The three methods in this calculator
1. Percentage of maximum heart rate
The simplest method. Your maximum heart rate is estimated with the HUNT formula from Norway's HUNT Fitness Study (3,320 healthy adults), which is more accurate than "220 minus age", especially after 40:
HRmax = 211 − 0.64 × age · Zone 2 = 60–70% of HRmax2. Heart-rate reserve (Karvonen)
Adds your resting heart rate, so fitter people with a low resting pulse get a range that suits them better:
Zone 2 = resting HR + 0.60–0.70 × (HRmax − resting HR)Because it starts from your resting heart rate, this method usually gives a higher range than % of max. Example: age 40 (HRmax 185), resting HR 60 → 135–148 bpm, against 111–130 bpm by % of max.
3. MAF 180
Phil Maffetone's rule of thumb for aerobic base training: 180 minus your age is the top of the range, and the bottom is 10 beats lower. Adjust it by −10, −5 or +5 for your health and training history.
Which number should I use?
Start with the heart-rate reserve range if you know your resting heart rate, otherwise % of max. Then check it with the talk test: in Zone 2 you can speak in full sentences but would rather not sing. If you are gasping at the bottom of the range, slow down; if you could chat all day at the top, it is fine to sit there.
Heart rate drifts upward in heat, when you are tired or dehydrated, and late in a long session. That is normal: slow down to stay in range rather than chasing a pace.
All five heart rate zones
| Zone | % of HRmax | Feels like | Use in Norwegian 4x4 training |
|---|---|---|---|
| Zone 1 | 50–60% | Very light | Warm-up start, cool-down, recovery days |
| Zone 2 | 60–70% | Light, conversational | Zone 2 sessions and the 3-minute 4x4 recoveries |
| Zone 3 | 70–80% | Moderate | End of the warm-up; not a target zone |
| Zone 4 | 80–90% | Hard | Lower half of the 4x4 interval zone (from 85%) |
| Zone 5 | 90–100% | Very hard | Upper half of the 4x4 interval zone (up to 95%) |
Want pace targets for the hard intervals too? The heart rate and pace calculator turns a 5K time, 2K row or FTP into a speed for each interval, and the 12-week plan generator schedules both kinds of session for you.
Frequently Asked Questions
What is Zone 2 heart rate?
Zone 2 is easy, steady aerobic exercise: about 60–70% of your maximum heart rate. You can breathe through your nose and hold a conversation in full sentences. It builds your aerobic base and helps you recover between harder sessions such as the Norwegian 4x4.
How do I calculate my Zone 2 heart rate?
Estimate your maximum heart rate (the HUNT formula is 211 − 0.64 × age) and take 60–70% of it. If you know your resting heart rate, the heart-rate reserve (Karvonen) method is more personal: resting HR + 60–70% of (max HR − resting HR). This calculator shows both, plus the MAF 180 formula.
Why do the three methods give different numbers?
They measure different things. % of max ignores how fit you are, heart-rate reserve accounts for a low resting heart rate, and MAF 180 is a rule of thumb for aerobic base training. All three are estimates of the same idea: the hardest effort that still feels easy. When they disagree, use the talk test.
Is Peter Attia’s Zone 2 the same as this?
Close, but not identical. Attia defines Zone 2 by blood lactate (around 2 mmol/L), which for many people lands near the top of the 60–70% range or slightly above it, roughly 70–80% of max heart rate in well-trained people. Without a lactate meter, aim for the top of your Zone 2 range while you can still speak in full sentences.
How much Zone 2 should I do with the Norwegian 4x4?
Most people do 1–2 Norwegian 4x4 sessions and 2 easy Zone 2 sessions of 30–45 minutes a week, plus strength training. Zone 2 builds the base; the 4x4 raises VO2 max. See the 12-week plan for a week-by-week version.
What if I take beta blockers?
Beta blockers lower both your resting and maximum heart rate, so formula-based zones will be too high. Tick the box for a rough 15% adjustment, but ask your doctor how to set your targets and rely more on perceived effort.
Sources
- Nes BM et al. Age-predicted maximal heart rate in healthy subjects: The HUNT Fitness Study. Scand J Med Sci Sports 2013;23(6):697-704.
- Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate; a longitudinal study. Ann Med Exp Biol Fenn 1957;35(3):307-15.
- Maffetone P. The Big Book of Endurance Training and Racing (MAF 180 formula). Skyhorse, 2010.
- San-Millán I, Brooks GA. Assessment of metabolic flexibility by means of measuring blood lactate, fat, and carbohydrate oxidation responses to exercise in professional endurance athletes and less-fit individuals. Sports Med 2018;48(2):467-479.