Heart rate zone calculator: max heart rate, zones and Norwegian 4x4

Enter your age, and the calculator works out your max heart rate, five training zones and the target heart rate for Norwegian 4x4 intervals. Add your resting heart rate to see where it sits.

Max heart rate by age

Your max heart rate is the highest number of beats per minute you can reach when you go all out. It falls with age, but varies a lot between people. Researchers at the Norwegian University of Science and Technology (NTNU) measured the max heart rate of 3,320 healthy adults in the HUNT study and found that 211 − 0.64 × age fits best on average (Nes et al., 2013). The older formulas, such as 220 minus age, underestimated max heart rate in everyone over 30.

Age	HUNT (211 − 0.64 × age)	Tanaka (208 − 0.7 × age)	220 − age
20	198	194	200
25	195	191	195
30	192	187	190
35	189	184	185
40	185	180	180
45	182	177	175
50	179	173	170
55	176	170	165
60	173	166	160
65	169	163	155
70	166	159	150
75	163	156	145
80	160	152	140

The Tanaka formula comes from a meta-analysis of 351 studies with 18,712 people and gives similar numbers. Any formula can be about 11 beats off either way. If you want to train precisely by heart rate, measure your max: wear a chest strap, warm up well, and finish with a few minutes as hard as you can, for example up a hill.

Heart rate zones on the Norwegian Olympic scale

Norwegian coaches and athletes use Olympiatoppen's intensity scale, which splits endurance training into five zones from I-1 to I-5 by percentage of max heart rate. These are the zones for a 40-year-old with a max of 185:

Zone	% of max	Heart rate (40 years)	Talk test
I-1 Very easy	55–72 %	102–133	You can talk without effort.
I-2 Fairly easy	72–82 %	133–152	You can say longer sentences.
I-3 Comfortably hard	82–87 %	152–161	You can say short sentences.
I-4 Hard	87–92 %	161–170	You can say a few words.
I-5 Very hard	92–100 %	170–185	One or two words at most.

Olympiatoppen points out that the scale is a guide. Heart rate varies by 6–12 beats from day to day and is affected by heat, sleep, fluids and stress, and wrist-based watches are less accurate than a chest strap. The talk test is a good check. More on building your training is on our exercise page.

The Norwegian 4x4 workout

The Norwegian 4x4 was developed by researchers at NTNU in Trondheim. You warm up for about 10 minutes, then do four intervals of 4 minutes at 90–95 % of your max heart rate, with 3 minutes of easy movement at around 70 % in between. The calculator above shows your own numbers.

In a study of 40 moderately trained men, four groups did the same total amount of work three times a week for eight weeks. The interval groups improved their maximal oxygen uptake (VO2max) significantly more than the groups that trained at a moderate pace, by 7.2 % with 4x4 intervals (Helgerud et al., 2007). VO2max is the most common measure of aerobic fitness.

The Generation 100 study followed 1,567 people in their seventies in Trondheim for five years. Overall, supervised training twice a week did not lower mortality compared with following the national activity guidelines. The group doing 4x4-style intervals had a lower mortality trend, but the difference was not statistically certain (Stensvold et al., 2020).

What your resting heart rate says

Your resting heart rate is your pulse when you have been lying still for a while. The British Heart Foundation says 60 to 100 beats per minute is typical for adults, and fit people often have a lower rate.

In a review of 46 studies with more than 1.2 million people, the risk of early death rose by 9 % for every 10 beats higher resting heart rate (Zhang et al., 2016). One measurement says little about you alone, but it is an easy number to follow over time. In an analysis of 191 studies, all kinds of exercise lowered the resting heart rate, with endurance training and yoga showing the clearest effect (Reimers et al., 2018).

Frequently asked questions

What is my max heart rate for my age?

A simple estimate is 211 minus 0.64 times your age, from a Norwegian study of 3,320 healthy adults. A 40-year-old gets 185 beats per minute. The formula can be about 11 beats off either way, so a measured max is always better.

What are the five heart rate zones?

Heart rate zones split training by how hard you work, as a percentage of your max heart rate. The Norwegian Olympic scale runs from I-1 (55–72 %) to I-5 (92–100 %). Most endurance training is done in the easy zones, with a smaller share of hard sessions.

How do you do the Norwegian 4x4?

Warm up for about 10 minutes, then run, cycle or row four intervals of 4 minutes at 90–95 % of your max heart rate. Between them, keep moving easily for 3 minutes at around 70 %. The whole session takes about 40 minutes.

What is a normal resting heart rate?

The British Heart Foundation says a resting heart rate between 60 and 100 beats per minute is typical for adults. Fit people often have a lower one, and a resting heart rate below 60 is common in endurance athletes.

Sources

• Nes et al. (2013): Age-predicted maximal heart rate in healthy subjects: The HUNT fitness study, Scand J Med Sci Sports
• Tanaka et al. (2001): Age-predicted maximal heart rate revisited, J Am Coll Cardiol
• Olympiatoppen: Intensity scale, version 2 (2024, in Norwegian)
• Helgerud et al. (2007): Aerobic high-intensity intervals improve VO2max more than moderate training, Med Sci Sports Exerc
• Stensvold et al. (2020): Effect of exercise training for five years on all cause mortality in older adults – the Generation 100 study, BMJ
• Zhang et al. (2016): Resting heart rate and all-cause and cardiovascular mortality in the general population: a meta-analysis, CMAJ
• Reimers et al. (2018): Effects of exercise on the resting heart rate: a systematic review and meta-analysis, J Clin Med
• British Heart Foundation: Checking your pulse

The calculator gives an estimate based on formulas and averages from large studies. It does not replace an assessment by a doctor. The numbers you enter stay in your browser and are not stored.