The quickest way to estimate your maximum heart rate is to subtract your age from 220. A 40-year-old, for example, gets an estimated ceiling of 180 beats per minute. That formula has been around for decades and remains the default on gym posters, fitness apps, and treadmill consoles. But it is a rough estimate with a margin of error that surprises most people, and a slightly better formula exists. How much that margin matters depends on what you plan to do with the number.
The Standard Formula and a Better Alternative
The “220 minus age” formula is often attributed to research from the early 1970s, but its origins were informal rather than rigorously tested. It became standard largely because it is easy to remember. In 2001, a meta-analysis pooling data from 351 studies involving nearly 19,000 people found that a revised equation fit the data more closely: 208 minus 0.7 times your age. A separate laboratory study by the same researchers produced a nearly identical result (209 minus 0.7 times age), reinforcing the finding.1PubMed. Age-predicted maximal heart rate revisited For a 40-year-old, the revised formula gives 180 beats per minute, which happens to match the old one at that age. But the two diverge for younger and older people. If you are 20, the classic formula says 200 while the revised one says 194. If you are 70, the classic says 150 and the revised says 159. The old formula tends to overestimate for younger adults and underestimate for older adults.
A 2023 meta-analysis that compared several age-based formulas across diverse populations confirmed this pattern, finding that the Fox formula (220 minus age) tended to overestimate max heart rate, while the Tanaka equation (the 208 minus 0.7 times age version) showed better accuracy with less average bias. The researchers recommended using the Tanaka equation when a formula is the only option, while noting the range of error that all such equations carry.2Sports Science & Health Advances. Meta-analysis of age-based maximum heart rate prediction equations: validating existing models across diverse populations
The Error Margin That Matters More Than the Formula
Whichever formula you pick, the individual error can be large. A study that tested several prediction equations against measured max heart rates found that even the best-performing formulas (Arena, Tanaka, and Gellish) had limits of agreement spanning roughly plus or minus 18 to 24 beats per minute.3PLoS One. Exploratory analysis of the accuracy of age-based maximal heart rate equations across cardiorespiratory fitness levels That means two 45-year-olds of the same fitness level could have true maximums that differ by 40 beats or more, even though the formula gives them the same number. The average bias was small (between about negative 3 and positive 6 beats per minute), so the formulas get it roughly right across a population. For any single person, though, the prediction can be meaningfully off.
This is worth understanding because many training programs set intensity zones as percentages of your max heart rate. If the formula overestimates your ceiling by 15 beats, every zone it generates will be too high, pushing you harder than intended. If it underestimates by the same amount, you might be training easier than you realize. The practical impact depends on how precisely you need to hit a target. For general health-oriented exercise, being off by 10 or 15 beats is rarely a problem. For athletes fine-tuning interval workouts or patients exercising under medical guidance, the error matters more.
Why Maximum Heart Rate Drops as You Age
The decline in maximum heart rate with age is one of the most predictable trends in exercise physiology, but the reason is not simply that your heart “wears out.” Research comparing younger and older men found that two factors account for most of the decline. The larger contributor is a reduction in intrinsic heart rate, which is the rate the heart beats on its own when stripped of nervous system input. The smaller but still meaningful contributor is a decrease in the heart’s responsiveness to adrenaline-like stimulation. Together, these two changes explained about 83% of the age-related difference in max heart rate, making the remaining gap statistically insignificant.4Journal of Applied Physiology. Decreased maximal heart rate with aging is related to reduced {beta}-adrenergic responsiveness but is largely explained by a reduction in intrinsic heart rate In plain terms, the heart’s built-in pacemaker slows down with age, and the chemical signals that make it speed up during intense effort become less effective. This process is gradual and largely independent of how fit you are.
Does Fitness Level Change Your Max?
A widespread assumption is that trained athletes have higher maximum heart rates than sedentary people. The evidence does not support this. While aerobic training clearly lowers your resting heart rate and your heart rate at any given submaximal workload, the general consensus in the literature is that max heart rate stays relatively unchanged regardless of training status.5PubMed. Evidence and possible mechanisms of altered maximum heart rate with endurance training and tapering A fit person and an unfit person of the same age may have similar peak heart rates during an all-out effort, even though the fit person can sustain much higher workloads at lower heart rates on the way there. This means formulas based on age alone are not systematically biased against active or sedentary people, though any individual can still deviate from the prediction.
There is a practical wrinkle here. Sedentary individuals attempting a max heart rate test may stop due to discomfort, lack of motivation, or muscle fatigue before they truly reach their cardiac limit. Their “measured” max can appear lower than their actual physiological max simply because they did not push long or hard enough to get there. This is one reason that lab-based tests with gradual protocols and strong verbal encouragement tend to produce the most reliable numbers.
Sex, Genetics, and Who the Formulas Miss
Most widely used formulas were developed from data dominated by men. When researchers have tested them on women, the mismatch shows. One study of women undergoing exercise treadmill testing found that only about half achieved the max heart rate predicted by the traditional formula, compared with roughly 70% who achieved the peak predicted by a women-specific formula. The regression equation that best fit their data was 201 minus 0.67 times age, which sits closer to the women-specific formula than to the traditional one.6PubMed. Impact of utilizing a women-based formula for determining adequacy of the chronotropic response during exercise treadmill testing The underestimation was most pronounced in older women. When a doctor uses the standard formula to judge whether a woman reached an adequate heart rate during a stress test, using the wrong equation can lead to the false conclusion that she did not try hard enough, potentially triggering unnecessary follow-up testing.
Genetics also play a role. Data from the HERITAGE Family Study found that the heritability of measured max heart rate was about 39% in Black participants and 44% in White participants, meaning a substantial chunk of the variation between individuals traces to inherited factors rather than age or fitness. The genetic contributors may differ between ethnic groups, which partly explains why a single formula cannot be equally accurate for everyone.7PubMed Central. Measured Maximal Heart Rates Compared to Commonly Used Age-Based Prediction Equations in the Heritage Family Study If your parents both had unusually high or low max heart rates, you may as well, regardless of what any formula predicts.
Medications That Move the Ceiling
Beta-blockers are the most common medication category that directly suppresses max heart rate, and the effect is large. One study found that people taking beta-blockers had a max heart rate about 19% lower than those who were not, averaging around 116 beats per minute compared with 145.8PubMed Central. The Impact of beta blockade on the cardio-respiratory system and symptoms during exercise Another large study found that beta-blocker therapy was associated with an 8% lower percentage of age-predicted max heart rate achieved during exercise stress testing.9PubMed Central. Effect of Beta-Blocker Therapy, Maximal Heart Rate and Exercise Capacity during Stress Testing on Long-Term Survival If you take a beta-blocker and try to use a standard formula to set training zones, those zones will be unreachable. You need either a measured max heart rate while on the medication, or a different method of gauging intensity altogether, such as perceived exertion scales.
Other medications and substances can also influence max heart rate. Calcium channel blockers of the non-dihydropyridine type (like diltiazem or verapamil) slow heart rate, though usually less dramatically than beta-blockers. Stimulants and high doses of caffeine can raise heart rate but do not reliably raise the true physiological maximum. If you are on any heart-rate-altering medication, the safest approach is to have your max heart rate assessed directly under medical supervision rather than rely on a formula.
Altitude and Exercise Type
Your max heart rate is not a fixed number that stays the same under all conditions. At high altitude, reduced oxygen availability causes meaningful drops. A study comparing heart rate at sea level versus high altitude found significant decreases in both healthy controls (from about 181 to 150 beats per minute) and patients with coronary artery disease (from about 166 to 139).10PubMed Central. Effects of altitude on exercise level and heart rate in patients with coronary artery disease and healthy controls Older research comparing sea-level residents with people living at around 3,800 meters confirmed that sojourners at altitude showed a lower max heart rate (about 175 versus 200 beats per minute at sea level), while long-term altitude residents showed adaptations that partially compensated for the oxygen deficit.11PubMed. Effects of hypoxia, heat, and humidity on physical performance If you normally train near sea level and then go hiking or running at elevation, your heart rate zones will need downward adjustment.
The type of exercise matters too. Swimming produces lower peak heart rates than running. One study found that peak heart rate during swimming was about 11 beats per minute lower than during treadmill running and about 13 beats lower than the age-predicted max. The researchers recommended subtracting 12 beats per minute from a treadmill-derived or age-predicted max when prescribing swimming intensity.12PubMed. Peak heart rates during maximal running and swimming: implications for exercise prescription The reasons include the horizontal body position in water, the cooling effect, and the smaller active muscle mass compared with running. Cycling typically falls between swimming and running. If you use heart rate to guide training in multiple sports, you may need separate zone ranges for each.
Measuring It Directly
If you want to know your actual max heart rate rather than rely on a formula, you can measure it. The gold standard is a graded exercise test in a laboratory, usually on a treadmill, where the workload increases progressively until you cannot continue. A clinician monitors your heart rate via an electrocardiogram throughout. Treadmill protocols are preferred because running uses large muscle groups and tends to produce higher peak heart rates than cycling or other modalities.13PubMed. Influence of cardiopulmonary exercise testing protocol and resting VO(2) assessment on %HR(max), %HRR, %VO(2max) and %VO(2)R relationships
One subtlety is that the specific test protocol matters. A study comparing a standard fitness test with a test specifically designed to elicit the highest possible heart rate found that the dedicated max test produced readings about 2 beats per minute higher on average.14PubMed. The relationship between maximum heart rate in a cardiorespiratory fitness test and in a maximum heart rate test The difference is small for most purposes, but it underscores that you are more likely to hit a true max when the test is designed for that goal and you are strongly motivated to push through the final seconds.
Not everyone has access to a lab. Field tests offer a practical alternative. A common approach is an all-out effort over a set distance or duration, like running 2,400 meters as fast as possible while wearing a heart rate monitor. Your peak reading during the final minutes gives a reasonable estimate of your max. These field tests correlate well with lab values for motivated participants, though less controlled conditions (weather, pacing errors, uneven terrain) introduce variability.
Can You Trust Your Wearable?
If you plan to find your max heart rate during a hard workout using a consumer device, the type of sensor matters. Chest straps that detect electrical signals from the heart consistently outperform wrist-based optical sensors. A study comparing several devices against a clinical electrocardiogram found that a chest strap (the Polar H7) had the highest agreement, with a concordance coefficient of 0.98. Among wrist-worn watches, the Apple Watch performed best at 0.96, while other wrist devices scored around 0.89.15PubMed Central. Accuracy of commercially available heart rate monitors in athletes: a prospective study
More recent testing has shown that the gap between wrist sensors and chest straps can widen during high-intensity and varied movements. During treadmill intervals, a newer Apple Watch maintained mean biases of only about 0 to 3 beats per minute across intensities, while a wrist-based Polar watch underestimated by 5 to 13 beats. During functional fitness movements like kettlebell swings and box jumps, the discrepancies for the Polar wrist device ballooned to 15 to 22 beats per minute of underestimation.16Translational Journal of the American College of Sports Medicine. The Agreement of Wrist-based Apple Watch and Polar Grit Heart Rate Monitoring as Compared With Chest-strap Polar Monitor The takeaway is that if you are trying to capture your true peak heart rate during an intense effort, a chest strap is the most reliable consumer option. Wrist watches work well enough for steady-state cardio but become less accurate when your heart rate is high and your wrists are moving rapidly.
Turning the Number Into Training Zones
Once you have a max heart rate, either from a formula or from measurement, the most common next step is to calculate training zones as percentages. A typical framework might set easy aerobic work at 60 to 70% of max, moderate work at 70 to 80%, and high-intensity efforts at 80 to 90% or above. These are rough guides, not physiological thresholds, but they give you a useful starting range.
An alternative approach is the Karvonen method, which factors in your resting heart rate. Instead of simply taking a percentage of your max, you calculate a percentage of your heart rate reserve (max minus resting) and then add your resting heart rate back. This produces slightly higher target numbers for the same percentage, which can be an issue. Research comparing different intensity calculation methods against the ventilatory threshold (the point where breathing becomes noticeably hard) found that for people with low or average fitness, the Karvonen formula at 77% significantly overestimated the appropriate intensity, while the straight percentage-of-max approach did not push past that threshold.17PubMed. Assessment of exercise intensity formulas by use of ventilatory threshold For highly fit individuals, the methods converged. If you are relatively new to exercise or have average fitness, the simpler percentage-of-max approach may be the safer bet for setting moderate-intensity targets.
A reassuring finding from a 12-week training study in obese men is that the choice of formula and zone method did not produce meaningful differences in outcomes. Groups using the Fox formula, the Tanaka formula, the straight percentage method, and the Karvonen method all improved their cardiovascular fitness, body weight, body fat, and resting heart rate to a similar degree.18PubMed Central. Effects of Aerobic Exercise on Physical Fitness in Obesity Using Fox vs. Tanaka’s Maximum Heart Rate and Percentage vs. Karvonen Methods The differences between formulas, in other words, are small enough that for general fitness purposes, just picking one and exercising consistently matters far more than picking the “right” one.
Children and Adolescents
The standard adult formulas do not translate well to younger populations. Children and teenagers tend to have higher maximum heart rates than adults, and the age-based decline is much flatter during the growing years. A study that measured max heart rate in children and adolescents found an average of about 201 beats per minute. The Tanaka equation’s prediction was closer to the measured values than the traditional 220-minus-age formula, which overestimated, but even the Tanaka equation had absolute errors averaging 8 to 10 beats per minute at the individual level.19PubMed Central. Evaluating the prediction of maximal heart rate in children and adolescents Regression models that tried to incorporate resting heart rate and maturity status did only slightly better, explaining less than 30% of the variation. For children in exercise programs or youth sports, heart rate targets based on adult formulas should be used cautiously, and perceived exertion or talk-test methods may be more practical.
Mental Fatigue and Perceived Effort
An interesting wrinkle for anyone who has tried to test their max after a long day of mentally demanding work: mental fatigue does not appear to lower your physiological ceiling. A systematic review examining the effects of mental fatigue on physical performance found that core physiological variables, including heart rate, blood lactate, and oxygen uptake, were unaffected by mental fatigue during exercise. What changes is perceived effort. Tasks feel harder after prolonged cognitive work, which can cause people to stop sooner during self-paced efforts. Your heart can still reach the same peak, but your brain may convince you to quit before you get there. If you are attempting a max heart rate test, doing it when you are mentally fresh will likely produce a more reliable result, not because your heart works differently when you are tired, but because you are more willing to push through the discomfort at the end.