Max Heart Rate

Max heart rate is the highest number of beats per minute your heart can reach during an all-out effort. It is a personal ceiling set mostly by age, and it anchors most heart rate zone systems, including the ones on Apple Watch and in Titan.

Every age formula, 220 minus age included, predicts the average for people your age. In the HUNT Fitness Study of 3,320 healthy adults, the typical miss was 10.8 beats per minute. A miss that size moves every zone boundary built on your max, and it can put a whole week of easy runs in the wrong zone.

01What the number measures

During a graded effort, heart rate climbs with workload until it stops climbing. That plateau is your max heart rate, often written HRmax. Robergs and Landwehr describe it as a ceiling that cannot be passed however hard you push. When you truly reach it, a measured max is accurate to within about 2 bpm.

Your max tells you little about your fitness. The HUNT researchers found no effect of sex, physical activity, VO2 max level or body mass index on how max heart rate relates to age, once they had verified that each subject reached a maximal effort. A fit 45-year-old and an unfit one can share the same max. The fit one does more work at every heart rate below it.

Two other heart rate numbers are easy to confuse with this one. Resting heart rate is the floor, measured at rest. Heart rate reserve is the span between that floor and your max, and the Karvonen method builds zones inside that span. Both methods need a max, so a wrong max carries into either one.

02Where 220 minus age came from

The most familiar formula has the weakest pedigree. In 2002, Robert Robergs and Roberto Landwehr tried to trace it. Textbooks usually credited Martti Karvonen or Per-Olof Åstrand. Karvonen told them he never published research on the formula. Åstrand said he had not published data that derived it, though he had called it a convenient approximation in talks.

The trail ended at a 1971 review of physical activity and coronary heart disease by Samuel Fox, John Naughton and William Haskell. Their figure plotted about 35 data points drawn from roughly 11 studies and unpublished compilations. No one ran a regression. The legend said that "no single line will adequately represent the data," and that 220 minus age "defines a line not far from many of the data points." When Robergs and Landwehr fitted a regression to those same points, they got 215.4 - 0.9147 × age with a standard error of 21 bpm. They concluded that 220 minus age "has no scientific merit."

The formula's slope causes a second problem. Subtracting your full age assumes max heart rate falls 1 bpm per year. The large studies below put the decline at 0.64 to 0.7 bpm per year. So 220 minus age runs high for young adults and low for older ones. It matches Tanaka's equation at exactly 40 years old. Tanaka's group concluded that the old formula underestimates max heart rate in older adults, so exercise prescribed from it runs easier than intended.

03The formulas that replaced it

Four equations from large or unusual datasets now carry most of the evidence.

Tanaka's lab study produced 209 - 0.7 × age, almost identical to the meta-analysis, and found no difference between men and women or across activity levels. Gellish's value is its design. It is longitudinal, so it follows the same people as they age, and it still landed on the same 0.7 bpm slope as the cross-sectional studies.

The formulas diverge most for older adults and for women.

At 60, the published equations span 20 bpm. Some of that gap comes from who was tested. Gulati's cohort were asymptomatic women given clinical stress tests, and the authors concluded that male-based formulas overestimate max heart rate in women. The HUNT data, from healthy volunteers who had to show a verified maximal effort, found the opposite. Older subjects and women had higher max heart rates than earlier equations predicted, and sex made no difference to the age relationship. Tanaka also found no sex difference. For a healthy, active woman, Nes or Tanaka is a reasonable starting estimate. Gulati's equation came from clinical stress testing, where the authors used it to judge heart rate response and mortality risk.

Robergs and Landwehr compiled 43 equations. Of the general ones, they rated 205.8 - 0.685 × age, from Inbar and colleagues, as most accurate, and they still called its 6.4 bpm error "unacceptably large."

04How wrong a formula can be for you

A formula's standard error describes how far individuals scatter around the line. The published figures cluster around 10 bpm.

• Robergs and Landwehr reported standard errors of 7 to 11 bpm across two decades of research, with most age-only equations above 10 bpm.
• The HUNT study reported 10.8 bpm.
• Kasiak and colleagues tested 13 equations against lab-measured max in 4,043 runners and 1,026 cyclists in 2023. Root mean square errors ran from 9.1 to 10.5 bpm, and most equations differed significantly from measured values.
• Ausland, Kelemen and Seiler collected self-reported field max heart rates from 4,375 endurance athletes in 2026. Tanaka's equation underestimated them by 4.8 bpm on average, with 95% limits of agreement from 18.5 bpm too low to 9.1 bpm too high.

If the errors are roughly normal, a 10.8 bpm standard error means about two people in three land within 11 bpm of their formula. About one in twenty misses by more than 21 bpm. You have no way to tell from the formula which group you are in.

What a miss does to your zones

Take a runner whose true max is 190 bpm and whose formula says 178, a miss of about one standard error. Titan's Zone 2 runs from 74% to 80% of max.

The predicted Zone 2 sits mostly inside the runner's true Zone 1. If they trust it, their Zone 2 sessions become recovery jogs. Their steady runs register as Zone 3, and because Titan weights each zone minute by its zone number, every one of those minutes adds more training load than it should. The same miss in the other direction pushes easy days up into moderate work.

Robergs and Landwehr judged that errors up to about 8 bpm are tolerable for setting training ranges. A one-standard-error miss already exceeds that.

05How to find your real max safely

A max test is a maximal effort, so screen yourself first. The American College of Sports Medicine bases its preparticipation screening on three things: how active you are now, whether you have signs or symptoms of cardiovascular, metabolic or renal disease or a known diagnosis, and how hard you plan to exercise. If you are inactive, have one of those conditions, or have had chest pain, fainting or unusual breathlessness during exercise, ask a clinician before an all-out effort. A supervised exercise test with ECG is the right tool in that case.

A lab test

A graded exercise test to exhaustion is the reference method. Speed or power rises in steps until you cannot continue, and an ECG records every beat. Sports medicine clinics and university labs offer these tests, often with VO2 max measured at the same time.

A field test

You can get close on your own. Warm up for 15 to 20 minutes, then run a ramp or hill test that finishes with two to three minutes at the hardest pace you can hold. The heart rate zones guide gives ramp step sizes for a trainer and a treadmill. Wear a chest strap. Test in the sport you train, because max heart rate differs between exercise modes, and zones built from a running max can be off for cycling.

Expect to try more than once. Boudet and colleagues put 16 endurance athletes through five exhaustive efforts each in the lab, in field tests and in races. Peaks averaged 194.3 bpm in the lab, 193.8 in the field and 192.3 in competition, with no significant difference. The same athlete's peak moved by about 6 bpm between attempts, and the highest value came from field tests for 7 athletes, races for 6 and the lab for 5, with two athletes peaking in two settings. One test can come in low. The highest clean value from several hard efforts is your best estimate.

Race and training data

You may already have your max on record. The finish of a 5K, a hill repeat that ended in a sprint, or the last interval of a hard session can all reach it. Ausland's athletes reported maxima from hard training and racing, and those values averaged above the age formulas.

Check any candidate peak against the samples around it before you trust it. A number that appears for a few seconds, jumps well above the seconds before and after, or exceeds anything you have seen in a race is more likely a sensor error than a new max.

06Does training change max heart rate

Age moves your max the most, at 0.64 to 0.7 bpm per year in the large studies. Training moves it far less, and mostly downward.

Tanaka's meta-analysis found that habitual activity did not change the age relationship. Smaller studies that tracked people through training disagree in the details. Zavorsky's 2000 review found max heart rate falls 3% to 7% with aerobic training and rises again with detraining or tapering. In the studies he pooled (n = 314), changes in max heart rate moved opposite to changes in VO2 max, with a correlation of −0.76. Whyte and colleagues measured young elite athletes in 2008 and found max heart rates of about 190 bpm in both endurance and anaerobic athletes, against 194.8 bpm in sedentary people of the same age.

If a block of endurance work leaves you with a max a few beats lower, you have not lost fitness. Zavorsky suggested athletes recheck max heart rate every training block of three to six weeks. For most people, once or twice a year is enough, plus a recheck after a long layoff.

Medications that act on heart rate change the picture more. Beta-blockers lower heart rate at every intensity, including the top. If you take one, a formula or a max measured before you started does not describe your heart now. Ask your prescriber how to set exercise intensity.

07How Apple Watch uses max heart rate

Apple's documentation says Heart Rate Zones on Apple Watch are a percentage of your maximum heart rate, calculated and personalized from your Health data. They appear only after you enter a date of birth in the Health app. You can switch to manual zones in Settings > Workout > Heart Rate Zones and enter lower and upper limits for Zones 2, 3 and 4. Apple's user guide does not publish the formula behind the automatic zones.

The watch's optical sensor is good enough for training and less reliable at the exact moment you need for a max test. Gillinov and colleagues compared wrist monitors with ECG in 50 adults on a treadmill, a bike and an elliptical in 2017. The Apple Watch had a concordance of 0.92 across all conditions, second only to a Polar chest strap at 0.996. None of the wrist devices was accurate on an elliptical with moving arm levers. Bent and colleagues found in 2020 that absolute error in wearable heart rate was about 30% higher during activity than at rest across the devices they tested.

Apple lists the conditions that degrade readings. Irregular movement such as tennis or boxing reads worse than running or cycling. Cold weather can reduce blood flow at the wrist below what the sensor needs. Some tattoos block the sensor's light. Apple's own fix is to pair a Bluetooth chest strap, which is also the right setup for a max test.

08How Titan sets your max heart rate

Titan sets its own max and builds its own zones. Zones you edit in the Apple Workout app do not change Titan's, and Titan's do not change Apple's.

With Use Custom Max Heart Rate turned off, Titan compares two numbers. The first is the single highest heart rate sample in Apple Health over the last 30 days, read from the Heart Rate sources you allow under data sources. The second is 220 minus your age, using the date of birth in Apple Health. Titan uses whichever is higher. If only one exists, it uses that one. If neither exists, it falls back to fixed thresholds. Titan keeps the result for up to seven days and recalculates right away when you change the custom max or edit a zone.

Titan's five zones start at 53%, 74%, 81%, 87% and 93% of that max. Your training load weights each workout minute by its zone number, so the max you use shapes your load as well as your zone chart. When the thresholds change, a Heart Rate Zones Updated card on Today shows the old and new values.

Two things follow from how auto mode works.

• The 220-minus-age floor sits above Tanaka's estimate before age 40 and below it after. A 25-year-old gets a floor of 195 bpm, where Tanaka predicts about 191. If your true max is lower than the floor, auto mode cannot go below it, and your zones run high.
• A race or max test sets your zones for the next 30 days. After that, with no hard efforts, the max drops back to a lower recent peak or to the age floor.

If you have measured your max with a chest strap or in a lab, turn on Use Custom Max Heart Rate. Tap your avatar on Today to open You, then open Your Training. The toggle and the Max Heart Rate value sit under Heart Rate, next to Heart Rate Zones. The value moves in 1 bpm steps from 80 to 240. If you also know your threshold heart rates, the heart rate zones help page explains how to move each zone's start so Titan's zones line up with them.

09Putting your max to work

Start with a formula only when you have nothing better, and pick Tanaka or Nes over 220 minus age. Treat the result as a guess with an error of about 10 bpm. Replace it with the highest clean peak from a field test or a hard race, recorded with a chest strap in the sport you train. Recheck after a long break, a big change in training, or any new medication that affects heart rate. Then set that number as a custom max, so your zones, your training load and every Zone 2 session start from your own heart.

10References

• Apple (accessed 2026). Get the most accurate measurements using your Apple Watch. Apple Support. https://support.apple.com/en-us/105002
• Apple (accessed 2026). View Heart Rate Zones on Apple Watch. Apple Watch User Guide. https://support.apple.com/guide/watch/view-heart-rate-zones-apd897dccddf/watchos
• Ausland Å, Kelemen B, Seiler S (2026). An exploratory study of maximal heart rate determination in endurance athletes, laboratory testing vs. field based. Frontiers in Sports and Active Living 8:1806303. https://doi.org/10.3389/fspor.2026.1806303
• Bent B et al. (2020). Investigating sources of inaccuracy in wearable optical heart rate sensors. npj Digital Medicine 3:18. https://doi.org/10.1038/s41746-020-0226-6
• Boudet G et al. (2002). Median maximal heart rate for heart rate calibration in different conditions, laboratory, field and competition. International Journal of Sports Medicine 23(4):290-297. https://doi.org/10.1055/s-2002-29081
• Gellish RL et al. (2007). Longitudinal modeling of the relationship between age and maximal heart rate. Medicine and Science in Sports and Exercise 39(5):822-829. https://doi.org/10.1097/mss.0b013e31803349c6
• Gillinov S et al. (2017). Variable accuracy of wearable heart rate monitors during aerobic exercise. Medicine and Science in Sports and Exercise 49(8):1697-1703. https://doi.org/10.1249/MSS.0000000000001284
• Gulati M et al. (2010). Heart rate response to exercise stress testing in asymptomatic women, the St. James Women Take Heart Project. Circulation 122(2):130-137. https://doi.org/10.1161/CIRCULATIONAHA.110.939249
• Kasiak PS et al. (2023). Validity of the maximal heart rate prediction models among runners and cyclists. Journal of Clinical Medicine 12(8):2884. https://doi.org/10.3390/jcm12082884
• Nes BM et al. (2013). Age-predicted maximal heart rate in healthy subjects, the HUNT Fitness Study. Scandinavian Journal of Medicine and Science in Sports 23(6):697-704. https://doi.org/10.1111/j.1600-0838.2012.01445.x
• Riebe D et al. (2015). Updating ACSM's recommendations for exercise preparticipation health screening. Medicine and Science in Sports and Exercise 47(11):2473-2479. https://doi.org/10.1249/MSS.0000000000000664
• Robergs RA, Landwehr R (2002). The surprising history of the "HRmax=220-age" equation. Journal of Exercise Physiology Online 5(2):1-10. https://www.asep.org/asep/asep/Robergs2.pdf
• Tanaka H, Monahan KD, Seals DR (2001). Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology 37(1):153-156. https://doi.org/10.1016/S0735-1097(00)01054-8
• Whyte GP et al. (2008). Training induced changes in maximum heart rate. International Journal of Sports Medicine 29(2):129-133. https://doi.org/10.1055/s-2007-965783
• Zavorsky GS (2000). Evidence and possible mechanisms of altered maximum heart rate with endurance training and tapering. Sports Medicine 29(1):13-26. https://doi.org/10.2165/00007256-200029010-00002