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Fat Burning Heart Rate

Your fat-burning heart rate is about 74% of your maximum heart rate — 133 bpm if you are 40. That is the average intensity where fat oxidation peaked in a laboratory study of 18 moderately trained cyclists. Type an age and the page returns that heart rate, the 71–77% band around it, the 92% ceiling above which fat oxidation was negligible, and the same figures for every age from 18 to 80. If you know your measured maximum, type that instead and every number moves to it.

Your age, and how you want your maximum

Between 14 and 90. The age formula is 208 − 0.7 × age, which gives 180 bpm at 40.

The highest rate you have actually seen on a chest strap or a watch, between 100 and 230. Leave it blank and the page uses the age formula instead. A measured maximum replaces the formula everywhere on the page, including the table highlight.

or press Enter

Your fat-burning heart rate

133 bpm

74% of the 180 bpm maximum the age formula gives a 40-year-old. The band around it is 128-139 bpm, and above 166 bpm fat oxidation was negligible in the same study.

Maximum used
180 bpm
Age-formula maximum
180 bpm
Fat-max share
74%
Band low (71%)
128 bpm
Band high (77%)
139 bpm
Negligible above (92%)
166 bpm

Fat-burning heart rate by age

Every age from 18 to 80, on the age formula only. The row for 40 is highlighted. All figures in bpm.

Age Max HR 74% target Band 71–77% Negligible above 92%

The other direction: a heart rate you have seen

Most people arrive with a number on a watch, not a question about percentages. Type the rate and the page reads it against your maximum: what share of it that is, and where it sits relative to the band and the ceiling.

Type a heart rate you have seen on a watch or a strap and the page reads it against the maximum above.

The gap between the formula and a measured maximum

The age formula is an average over thousands of people, so it is wrong for most individuals by some amount. If you have a measured maximum, this block says how far off the formula is for you and what that does to the 74% target — the arithmetic nobody prints next to a zone chart.

Type a measured maximum heart rate above and the page shows how far the age formula is from it, and what that does to the 74% target.

What this page does

A fat burning heart rate answers a narrower question than the phrase suggests. Fat is oxidised at every intensity you can hold; what changes with intensity is how much of the energy you are using comes from fat. The number this page prints is the intensity at which the rate of fat oxidation reached its peak in a laboratory measurement, and the best-documented estimate of that intensity is 74% of maximum heart rate — the mean Achten, Gleeson and Jeukendrup reported in 2002 from 18 moderately trained cyclists who rode a graded test to exhaustion with fat oxidation measured by indirect calorimetry.

The page takes an age, turns it into a maximum heart rate with the equation Tanaka, Monahan and Seals published in 2001, and prints 74% of it. Around that number it prints the band the same paper reported (71 to 77%, its mean plus and minus one standard deviation), the ceiling above which fat contributed almost nothing (92%), and the same figures for every age from 18 to 80. If you know your measured maximum, type it and every number on the page moves to your own maximum instead of the formula's.

This is not the VO2 max calculator, which estimates a VO2 max from two field tests and deliberately leaves training zones out. It is not the VO2 max by age page either, which reads a VO2 max against the reference band for a decade. This page answers one question — at what heart rate did fat oxidation peak — from one source, and gives one intensity rather than a five-zone chart. Five-zone models differ by author, and this page has no source that would let it pick one.

How the numbers are calculated

Three published numbers do all the work, and none of them is this site's own invention. The first turns an age into a maximum heart rate:

HRmax = 208 − 0.7 × age

Tanaka H., Monahan K.D. and Seals D.R. (2001), Journal of the American College of Cardiology 37(1):153–156, DOI 10.1016/S0735-1097(00)01054-8. The equation came out of a meta-analysis that collected group mean maximum heart rates from 351 studies, 492 groups and 18,712 subjects, with a correlation of r = −0.90 against age. It was then cross-validated in a controlled laboratory study of 514 healthy subjects, where the regression was 209 − 0.7 × age — almost the same line. The same paper reports that the line did not differ between men and women and was not moved by habitual activity level, and that the older 220 − age shortcut underestimates maximum heart rate in older adults.

The second and third numbers come from the same paper, and they are shares of that maximum:

HRfat = 0.74 × HRmax    band = 0.71–0.77 × HRmax    ceiling = 0.92 × HRmax

Achten J., Gleeson M. and Jeukendrup A.E. (2002), Medicine & Science in Sports & Exercise 34(1):92–97, DOI 10.1097/00005768-200201000-00015. Eighteen moderately trained cyclists performed a graded test to exhaustion; fat oxidation was measured by indirect calorimetry. The paper reports Fat(max) as 64 ± 4% of VO2max and 74 ± 3% of maximum heart rate, and locates the Fat(max) zone — the intensities with fat oxidation within 10% of the peak rate — between 55 ± 3 and 72 ± 4% of VO2max. Above 89 ± 3% of VO2max, reported as 92 ± 1% of maximum heart rate, the contribution of fat oxidation became negligible. That is where the ceiling on this page comes from.

Two honest notes about the band. 71 and 77 are 74 minus and plus three, which is one standard deviation of the group mean; they are not a personal range, and the paper itself found a wide spread between individuals. A later study from the same group, on 55 endurance-trained men, put the coefficient of variation of that estimate at 9.0 to 9.5% — so the band is the uncertainty in the number, not a corridor you have to stay inside. And the 74% was measured on a cycle ergometer; a treadmill comparison found the intensity was not significantly different between modes (62.1 ± 3.1% against 59.2 ± 2.8% of VO2max) while the peak rate was higher running than cycling (0.65 ± 0.05 against 0.47 ± 0.05 grams per minute), so the percentage transfers between modes better than the grams do.

A worked example: a 40-year-old on the age formula

The maximum is 208 − 0.7 × 40 = 180 bpm. The fat-burning heart rate is 0.74 × 180 = 133.2, printed 133 bpm. The band is 0.71 × 180 = 127.8 and 0.77 × 180 = 138.6, printed 128 and 139 bpm. The ceiling is 0.92 × 180 = 165.6, printed 166 bpm. Four figures, one maximum, three published shares.

The same 40-year-old with a measured maximum of 192 bpm gets a target of 0.74 × 192 = 142.08, printed 142 bpm — nine beats above the formula's answer. That gap is the whole reason the measured field exists: the formula is 12 bpm low here, and the target moves with it.

  • HRmax — maximum heart rate in beats per minute, either from 208 − 0.7 × age or from a number you measured.
  • HRfat — 74% of that maximum. The mean intensity at which fat oxidation peaked in the 2002 study, not a threshold you cross.
  • band — 71% to 77% of the maximum: the study's mean plus and minus one standard deviation.
  • ceiling — 92% of the maximum: the intensity above which fat oxidation contributed almost nothing, reported by the same paper as 89 ± 3% of VO2max.
  • rounding — every figure is a whole number of beats, rounded once at the end. 133.2 prints 133; 165.6 prints 166.

The by-age table, and how to read it

The table above holds one row for each age from 18 to 80, with the maximum the age formula gives, the 74% target, the 71–77% band and the 92% ceiling on the same line. The row for the age you typed is highlighted, so the table doubles as a way of reading the page at a glance rather than a separate reference you have to hunt through.

Two notes on reading it. Every row is the age formula only — a measured maximum does not change the table, because the table is the formula's output for every age, and your measured value belongs to you alone; the stats row above the table is where your own maximum shows up. And the numbers are whole beats, so a row can be one beat away from the exact product: at 40 the exact target is 133.2, which the table and the verdict both print as 133.

The reverse direction: a heart rate you have seen

Most visitors arrive with a number, not a percentage: the watch said 152, the strap said 148, the machine at the gym said 160. The reverse block takes that number, divides it by the maximum above, and tells you what share of your maximum it is and where it sits — below the band, inside it, above it and below the ceiling, or above the ceiling.

The arithmetic is one division. A reading of 152 bpm against a maximum of 180 is 152 ÷ 180 = 84.4% of maximum, which is above the 139 bpm top of the band and below the 166 bpm ceiling: fat was still being used, at a lower rate per minute than at the peak. Change the maximum and the same reading lands somewhere else, which is the point — the percentage is the answer, the beats are just how you read it off a device.

The gap between the formula and a measured maximum

An equation fitted to 18,712 people is a statement about the middle of a distribution, so it is wrong for most individuals by some amount — and the error runs in both directions. The gap block exists because almost every zone chart on the internet multiplies a formula and never says how much the formula can be off. Here the gap is printed: type a measured maximum, and the page returns the difference between it and the formula, then the difference that makes to the 74% target.

It is the same arithmetic as the worked example. A 40-year-old with a measured 192 bpm is 12 beats above the formula's 180; the target goes from 133 to 142 bpm. A 40-year-old who measured 168 is 12 beats below, and the target goes the other way. Nothing is corrected or smoothed — the measured number is used as given, everywhere on the page, because a maximum you measured is a better input than one fitted to a population.

The four sources, and exactly what each supplies

  • Tanaka H., Monahan K.D., Seals D.R. (2001) — Age-predicted maximal heart rate revisited, Journal of the American College of Cardiology 37(1):153–156, DOI 10.1016/S0735-1097(00)01054-8. Supplies the equation 208 − 0.7 × age, its derivation (351 studies, 18,712 subjects, r = −0.90) and its cross-validation in 514 healthy adults (209 − 0.7 × age).
  • Achten J., Gleeson M., Jeukendrup A.E. (2002) — Determination of the exercise intensity that elicits maximal fat oxidation, Medicine & Science in Sports & Exercise 34(1):92–97, DOI 10.1097/00005768-200201000-00015. Supplies 74 ± 3% of maximum heart rate, the 55–72% VO2max zone, and the 92 ± 1% of maximum heart rate where fat oxidation became negligible.
  • Achten J., Jeukendrup A.E. (2003) — Maximal fat oxidation during exercise in trained men, International Journal of Sports Medicine 24(8):603–608, DOI 10.1055/s-2003-43265. Supplies the spread: 55 endurance-trained men, peak fat oxidation 0.52 ± 0.15 grams per minute at 62.5 ± 9.8% of VO2max, coefficient of variation 9.0–9.5%.
  • Achten J., Venables M.C., Jeukendrup A.E. (2003) — Fat oxidation rates are higher during running compared with cycling over a wide range of intensities, Metabolism 52:747–752, DOI 10.1016/S0026-0495(03)00068-4. Supplies the running-versus-cycling comparison: 62.1 ± 3.1% against 59.2 ± 2.8% of VO2max, not significantly different, with peak rates of 0.65 ± 0.05 against 0.47 ± 0.05 grams per minute.

Nothing on this page is transcribed from a zone chart, a coaching site or another calculator. The four constants above are the only outside numbers, and every figure the page prints is arithmetic on them.

Supported range and limits

  • Age: 14 to 90, whole years. Outside that range the equation was not fitted to you and the page refuses the input rather than guessing.
  • Measured maximum: 100 to 230 bpm, whole beats, or leave the field blank.
  • Heart rate you have seen: 30 to 250 bpm, for the reverse lookup.
  • Rounding: whole beats, one rounding at the end. No figure is rounded twice.
  • Cost: none. No account, no email, no paywall, no daily limit, no request to a server.
  • Privacy: every number is computed in your browser. Nothing you type is sent anywhere or stored — reload the page and it is gone.
  • Works offline once the page has loaded, and on a phone.

What this page deliberately does not do

  • No calorie or fat-gram estimate. Turning an intensity into grams per minute needs your body mass, the mode and a substrate-use measurement; the study reports rates for its own subjects, not a formula for yours. Printing a number here would be an invention.
  • No five-zone chart. Zone models differ by author and by the percentages each one picks. This page gives one intensity from one source instead of a chart with five unsourced boundaries.
  • No heart-rate-reserve conversion. The study reports its result as a share of maximum heart rate. Converting between %HRmax and %HRR needs a model this page has no source for, so it does not do it.
  • No measurement protocol. It does not tell you how to test your own maximum; a maximum test is a hard effort and, for some people, a medical one. It uses a measured number if you already have one.
  • No session prescription. No durations, no intervals, no weekly volume, no programme. One intensity is not a training plan.
  • No medical advice. If you have a heart condition, or take medication that changes your heart rate, this number is not a target to train to.
  • No VO2 max estimate. That is the VO2 max calculator, and the reference bands by decade are the VO2 max by age page.

Questions

What is a fat-burning heart rate?

About 74% of your maximum heart rate. That is the average intensity at which fat oxidation reached its peak in a graded laboratory test on 18 moderately trained cyclists, reported as 64 +/- 4% of VO2max and 74 +/- 3% of maximum heart rate (Achten, Gleeson and Jeukendrup, 2002). For a 40-year-old on the age formula the maximum is 180 bpm, so the fat-burning heart rate is 133 bpm. Fat is oxidised at every intensity; this number marks where the rate of fat oxidation was highest, not where it starts or stops.

Is there a heart rate that burns fat and nothing else?

No. Fat and carbohydrate are both used at every intensity you can hold, and what changes is the mix. The band this page prints is where the rate of fat oxidation was within a few beats of its peak, and the ceiling it prints is where fat oxidation had become negligible - in the same study that was 89 +/- 3% of VO2max, reported as 92 +/- 1% of maximum heart rate. Below the ceiling you are still burning fat, just at a lower rate per minute.

How do I work out my maximum heart rate?

The equation this page uses is 208 minus 0.7 times your age, from Tanaka, Monahan and Seals (2001). It came from a meta-analysis of 351 studies covering 18,712 subjects and was cross-validated in 514 healthy adults, where the laboratory equation was 209 minus 0.7 times age. The older 220-minus-age shortcut is the one that paper says underestimates maximum heart rate in older adults. A measured maximum beats any equation; type it in and every figure on the page uses it.

What is the fat-burning zone in bpm for a 40-year-old?

133 bpm is the target, 128 to 139 bpm is the band around it, and 166 bpm is the ceiling above which fat oxidation was negligible. The arithmetic: the age formula gives 208 - 0.7 x 40 = 180 bpm; 0.74 x 180 = 133.2, printed 133; 0.71 x 180 = 127.8 and 0.77 x 180 = 138.6, printed 128 and 139; 0.92 x 180 = 165.6, printed 166. All four are the same maximum multiplied by a published share.

Does the fat-burning zone burn more fat than a harder session?

The rate of fat oxidation per minute peaks at that intensity and falls above it, which is what the study measured: above the ceiling, fat contributed almost nothing. That is a statement about the rate, not about the total for a session, and this page does not estimate calories or grams, so it does not claim which of two sessions burns more fat overall. It gives you the intensity where the rate peaked and stops there.

Why is the band 71 to 77% of maximum heart rate?

Because 74 +/- 3% is the mean and one standard deviation the paper reported, and 71 and 77 are that mean minus and plus one standard deviation. It is the spread of the group average, not a personal range: the same group's individual peaks varied much more widely, and a later study of 55 endurance-trained men put the coefficient of variation of that estimate at 9.0 to 9.5%. Treat the band as the uncertainty in the number, not as a corridor you have to stay inside.

Does running give the same number as cycling?

The intensity is close and the rate is not. In 12 moderately trained men the intensity that produced peak fat oxidation was not significantly different between treadmill and cycle ergometer - 62.1 +/- 3.1% against 59.2 +/- 2.8% of VO2max - but the peak rate itself was higher running than cycling, 0.65 +/- 0.05 against 0.47 +/- 0.05 grams per minute (Achten, Venables and Jeukendrup, 2003). So the percentage transfers between modes better than the grams do. The 74% figure this page uses was measured on a cycle ergometer.

Can I use this page to plan my training?

It gives you one intensity from one published source, which is what it is for. It does not prescribe sessions, intervals, durations or weekly volume, it does not know your health, and it is not medical advice. If you have a heart condition or take medication that changes your heart rate, the number on this page is not a target to train to - ask the person who treats you.