Getting training zones that are actually yours
1. Enter your age
Every age-predicted maximum heart rate formula is a population average with a standard deviation of roughly 10 to 12 beats per minute around it. That is worth sitting with: two people of the same age can genuinely differ by twenty beats at maximum, and no formula can tell which of them you are.
2. Choose your sex
Not cosmetic. The classic formulas were fitted on predominantly male cohorts, and a formula derived specifically in women gives a meaningfully different answer — typically lower, and increasingly so with age. If you are a woman, a maximum from a male-derived equation has been overestimating your zones for years.
3. Measure your resting heart rate properly
First thing in the morning, before getting out of bed, before caffeine. Count for a full sixty seconds rather than fifteen and multiplying, which magnifies any miscount fourfold. Take it across several mornings and use the average; a single reading after an unusual night tells you about the night.
4. Understand what adding a resting rate does
It switches the tool onto the Karvonen method, which works from heart-rate reserve rather than percentage of maximum. These are different scales with different percentage bands, and the tool now applies the correct bands to each. The previous version applied one set of percentages to both, which quietly moved every zone.
5. Read the zones as ranges, not as targets
Zone boundaries are conventions. Nothing metabolic happens at exactly 76 per cent of maximum. The useful distinction is between easy, moderate and hard, and most people training for general health need far more of the first than they think.
6. Check the medication note if it applies to you
If you take a beta blocker or certain other rate-limiting drugs, every number on this page is wrong for you in a predictable direction, and the page now says so rather than leaving you to discover it mid-session.
Why 220 minus age is the wrong formula, and what replaced it
The 220-minus-age rule has no single published derivation. It appears to have emerged from a rough reading of a scatter of studies in the 1970s and became universal because it is easy to remember. It has been known to be biased for decades.
Tanaka, Monahan and Seals published a meta-analysis in the Journal of the American College of Cardiology in January 2001 — “Age-predicted maximal heart rate revisited” — which produced the equation 208 − (0.7 × age). It fits the data better across the age range, and the difference is not academic. At 20 the two formulas agree almost exactly. At 50 they differ by 3 beats. At 70 they differ by 9. At 80, by 12.
Tanaka is not the only revision. Nes and colleagues examined the relationship in 3,320 healthy men and women in the HUNT Fitness Study, publishing in Scandinavian Journal of Medicine & Science in Sports in December 2013, and arrived at 211 − (0.64 × age) — close to Tanaka and derived from a single large modern cohort rather than pooled older studies. That two independent efforts land near each other and away from 220-minus-age is the point.
The bias runs in a consistent direction: 220-minus-age underestimates maximum heart rate in older adults. So an older person following its zones is training easier than they think they are, at exactly the age when the margin between useful and pointless training intensity narrows.
The previous version of this page knew all of this. It printed “Max HR (Tanaka) 208 − 0.7 × age” in a box on the page — and then computed the headline figure, the gauge and every single training zone from hrmax = 220 − age. A 70-year-old was shown a Zone 2 of 84 to 98 beats per minute where the formula displayed alongside it gives 91 to 106. Displaying the better answer while using the worse one is a peculiar kind of defect: everything on the page looks informed, and the numbers are wrong anyway.
The formula derived in women, because the others were not
Gulati and colleagues published heart-rate response data from the St James Women Take Heart Project in Circulation on 13 July 2010, based on exercise stress testing in a large cohort of asymptomatic women. The resulting equation is 206 − (0.88 × age).
It matters because the classic formulas were derived from cohorts that were overwhelmingly male, and women’s peak heart rates are on average lower. At 50, Tanaka gives 173 and Gulati gives 162 — eleven beats apart. A woman using a male-derived maximum has been placing every zone boundary too high, which in practice means training harder than intended in every session and finding the “easy” zone strangely difficult.
Both are shown here so you can see the difference rather than be handed one number.
Two scales, two sets of percentages, and the bug that mixed them
There are two standard ways to define a training zone, and they are not interchangeable.
Percentage of maximum heart rate is the simple one: 70 per cent of your maximum is just that number multiplied by 0.7.
Heart-rate reserve, the Karvonen method, works from the range between your resting and maximum rates: target = resting + (percentage × (maximum − resting)). It is generally considered more individualised, because it accounts for the fact that your heart is already beating before you start. The method comes from Karvonen, Kentala and Mustala, writing in Annales Medicinae Experimentalis et Biologiae Fenniae in 1957 — it is nearly seventy years old and still the standard way of individualising a target range.
Because the second method starts counting from your resting rate rather than from zero, the same percentage means something different on each scale. The American College of Sports Medicine publishes the correspondence, and it is not one to one: moderate intensity is 64 to 76 per cent of maximum, but 40 to 59 per cent of reserve. Vigorous is 77 to 95 per cent of maximum, but 60 to 89 per cent of reserve.
The previous build applied the same 50/60/70/80/90 boundaries to both. Enter a resting heart rate and it switched silently to Karvonen while keeping the percentage-of-maximum bands — so at age 30 with a resting rate of 60, “Zone 2” moved from 114–133 to 138–151 beats per minute. A 24-beat jump, same label, no explanation, on a method the page described as “more accurate”. The correct bands are now applied to whichever scale is in use.
What the zones are actually for
- Zone 1, very light — warm-up, cool-down, recovery between hard days.
- Zone 2, light — the aerobic base. Conversational pace. This is where most endurance training should live, and where most people spend the least time because it feels too easy to be doing anything.
- Zone 3, moderate — aerobic capacity. Comfortably hard; talking becomes short sentences.
- Zone 4, hard — around the lactate threshold. Sustainable for perhaps an hour when trained, and only a few words at a time.
- Zone 5, maximum — intervals only, minutes at a time.
The best-supported general pattern for endurance work is roughly eighty per cent easy and twenty per cent hard, with relatively little in the moderate middle. The common failure is the opposite: too much moderate, which is hard enough to accumulate fatigue and not hard enough to drive adaptation.
A practical cross-check that needs no equipment: if you can hold a conversation you are in the moderate range or below; if you can only manage a few words at a time, you are in the vigorous range. The talk test agrees with measured intensity surprisingly well and does not require a formula to be right about you.
Reading a resting heart rate against the clinical range, not just a fitness scale
Normal resting heart rate for adults is 60 to 100 beats per minute. Trained endurance athletes commonly sit in the 40s and occasionally lower, and in that context it reflects a heart that moves more blood per beat.
Both ends of that range have clinical names, and the previous version of this page used neither. Above 100 at rest is tachycardia. Below 60 is bradycardia. The old build called anything over 80 “on the higher side” and never mentioned 100 at all — so a resting rate of 110 came back as a comment on fitness rather than as a finding. Below 60 was reported as good fitness, with no acknowledgement that in someone who is not an endurance athlete it can indicate a conduction problem, thyroid disease or a medication effect.
Neither is automatically alarming and neither should be silently reclassified as a compliment. What matters is context: whether it is new, whether it came with a change of medication, and whether it comes with dizziness, fainting, breathlessness, chest discomfort or unusual fatigue. Any of those with a rate outside the normal range is a reason to see a doctor.
Resting heart rate is also one of the more useful things you can track over time. A trend upward of five to ten beats over several mornings often precedes noticeable illness, overtraining or a period of poor sleep by a day or two.
If you take a beta blocker, none of these numbers are yours
This section did not exist before, and its absence was the most consequential omission on the page.
Beta blockers — atenolol, bisoprolol, metoprolol, propranolol and others — work by blunting the effect of adrenaline on the heart. They lower resting heart rate and they lower maximum heart rate substantially, often by twenty to thirty beats per minute or more. Every age-predicted formula on this page assumes an untreated heart, so every figure it produces will be too high for someone taking one.
Rate-limiting calcium channel blockers such as diltiazem and verapamil have a similar effect. Some antiarrhythmics do too. Thyroid medication, decongestants, stimulants and several asthma inhalers push in the other direction.
The people most likely to be prescribed these drugs — those with high blood pressure, angina, arrhythmia or established heart disease — overlap heavily with the people looking up heart-rate zones because they have been advised to exercise. If that is you, ask your doctor or a cardiac rehabilitation team for a target range based on an actual exercise test, and use rating of perceived exertion or the talk test in the meantime. A formula cannot know what your medication is doing.
What this page is not
It is arithmetic on published equations, with their sources and their error margins stated. It is not a diagnosis, not an exercise prescription and not medical advice.
Please see a doctor rather than relying on this page if you have a diagnosed heart condition, chest pain or pressure on exertion, fainting or near-fainting, palpitations that are new or sustained, or unexplained breathlessness — and before starting vigorous exercise if you have been inactive for a long period, have cardiovascular risk factors, or are over 40 and unaccustomed to hard effort. The only genuinely accurate way to know your maximum heart rate is a supervised exercise test, and that is not something to attempt alone from a web page.
Nothing you enter is transmitted
Age, sex and resting heart rate are used locally in your browser to compute the figures. Nothing is sent, stored or logged; there is no account and no upload, and the page keeps working with the connection off once loaded.
Questions people ask about heart rate
Which maximum heart rate formula should I use?
Tanaka rather than 220-minus-age, and Gulati if you are a woman. All three are population averages with roughly 10 to 12 beats of standard deviation, so treat any of them as the centre of a range rather than as your number.
Why is my calculated maximum different from what my watch says?
Most watches use 220-minus-age unless you have changed the setting, or they have observed a higher rate during a hard session and adopted it. An observed maximum from a genuinely maximal effort is better evidence than any formula.
What is a good resting heart rate?
The normal adult range is 60 to 100. Fitter people generally sit lower, and endurance athletes are often in the 40s. What matters more than the absolute figure is your own trend and whether a change came with symptoms.
Is a resting heart rate over 100 dangerous?
It is called tachycardia and it warrants medical assessment, particularly if it is persistent, new, or accompanied by dizziness, breathlessness or chest discomfort. Fever, dehydration, anxiety, caffeine, anaemia and thyroid problems are all common causes.
What does Zone 2 training actually do?
It builds aerobic base — mitochondrial density, capillary networks, fat oxidation — with low fatigue cost, which is why it can be done in volume. It should be genuinely conversational, and most people ride or run it too hard.
Why did my zones change when I entered my resting heart rate?
Because it switches to the Karvonen heart-rate reserve method, which is a different scale. The correct percentage bands for that scale are now applied — moderate is 40 to 59 per cent of reserve against 64 to 76 per cent of maximum. In the previous version the same bands were applied to both, which moved every zone without saying so.
I am on a beta blocker. Can I use these zones?
No. Beta blockers lower both resting and maximum heart rate substantially, so every figure here will be too high for you. Ask for a target range based on an exercise test, and use perceived exertion or the talk test meanwhile.
How accurate are wrist-based heart rate monitors?
Good at rest and during steady effort; less reliable during intervals, weight training and anything involving wrist movement or grip. A chest strap remains considerably more accurate for hard or variable work.
Do you store my details?
No. Nothing is saved or transmitted.
Sources behind these numbers
- Tanaka H, Monahan KD, Seals DR, “Age-predicted maximal heart rate revisited”, Journal of the American College of Cardiology, January 2001, 37(1):153–156 (PMID 11153730) — the 208 − 0.7 × age equation used here.
- Gulati M et al, “Heart rate response to exercise stress testing in asymptomatic women: the St James Women Take Heart Project”, Circulation, 13 July 2010, 122(2):130–137 (PMID 20585008) — the 206 − 0.88 × age equation for women.
- Nes BM, Janszky I, Wisløff U, Støylen A, Karlsen T, “Age-predicted maximal heart rate in healthy subjects: The HUNT Fitness Study”, Scandinavian Journal of Medicine & Science in Sports, December 2013, 23(6):697–704 (PMID 22376273) — 3,320 healthy adults, 211 − 0.64 × age.
- Karvonen MJ, Kentala E, Mustala O, “The effects of training on heart rate: a longitudinal study”, Annales Medicinae Experimentalis et Biologiae Fenniae, 1957, 35(3):307–315 (PMID 13470504) — the origin of the heart-rate reserve method.
- American College of Sports Medicine — the intensity bands, and the correspondence between percentage of maximum and percentage of heart-rate reserve.
- American Heart Association, for target heart rate guidance and the normal resting range.
- NHS — heart palpitations and ectopic beats, for when a rate or rhythm needs medical attention.
- CDC — physical activity basics, for the weekly targets the zones serve.
Tools people open next to this one
- Calories Burned Calculator — MET-based energy cost, scaled to your own resting metabolism.
- Sleep Calculator — resting heart rate responds to sleep faster than to almost anything else.
- Water Intake Calculator — dehydration raises heart rate at any given workload.