The most common way to estimate your maximum heart rate is to subtract your age from 220. A 40-year-old, for example, gets an estimated max of 180 beats per minute. This formula has been the default since the 1970s, but it’s a rough estimate with a margin of error that can be off by 10 to 12 bpm in either direction. Several newer formulas do a better job, and which one fits you best depends on your age and sex.
The Standard Formula: 220 Minus Age
The classic equation is simple: Max heart rate = 220 – your age. It was introduced by Fox and colleagues in 1971 and became the go-to shorthand in gyms, fitness trackers, and cardiology offices. Its appeal is obvious: anyone can do the math in their head.
The problem is accuracy. When researchers compare this formula’s predictions against actual max heart rates measured on a treadmill with gas analysis and heart monitoring, the gap is significant. The formula tends to overestimate max heart rate in younger people and underestimate it in older adults. For a 25-year-old, it might predict 195 bpm when their true max is closer to 190. For a 65-year-old, it might predict 155 when they can actually hit 162. That kind of error matters if you’re using heart rate zones to guide your training.
The Tanaka Formula: A More Accurate Option
In 2001, researcher Hirofumi Tanaka and colleagues analyzed data from 351 studies and proposed a revised equation: Max heart rate = 208 – (0.7 × age). For a 40-year-old, that gives 180 bpm, which happens to match the old formula. But the two equations diverge at the extremes. A 25-year-old gets 190.5 bpm (versus 195 from the classic formula), and a 65-year-old gets 162.5 (versus 155).
Studies on recreational marathon runners found the Tanaka formula matched measured max heart rates well in men. In women, however, it overestimated by about 5 bpm. The old Fox formula underestimated by about 3 bpm in men. Neither formula is perfect, but Tanaka’s version corrects the biggest errors at the age extremes where the classic formula drifts the most.
A Formula Designed for Women
Research published in the American Heart Association’s journal Circulation found that the traditional 220-minus-age formula, which was derived mostly from male subjects, consistently overestimates peak heart rate in younger women and underestimates it in older women. Cardiologist Martha Gulati and her team studied 5,437 asymptomatic women and developed a sex-specific equation: Max heart rate = 206 – (0.88 × age).
For a 40-year-old woman, this gives about 171 bpm, compared to 180 from the classic formula. That’s a meaningful difference. It also has real clinical consequences: using the wrong max heart rate during exercise stress testing led to higher rates of inconclusive results in women, because the target was set too high. If you’re a woman using heart rate zones for fitness or if you’ve ever been told your stress test was “nondiagnostic,” this formula may give you a more realistic number to work from.
The HUNT Fitness Study Formula
Norwegian researchers at the Norwegian University of Science and Technology measured actual max heart rates in 3,320 healthy adults ranging from age 19 to 89 and developed another equation: Max heart rate = 211 – (0.64 × age). For a 40-year-old, that predicts about 185 bpm.
This formula was built from a large, diverse age range with lab-verified measurements. However, when tested against other populations, it has shown a tendency to overpredict, particularly in certain age groups. No single formula works perfectly across all people, which is why these alternatives exist. The Nes formula is worth trying if other estimates don’t seem to match your experience during hard workouts.
Quick Reference by Age
Here’s how the main formulas compare across ages:
- Age 25: Fox = 195, Tanaka = 190, Gulati (women) = 184, Nes = 195
- Age 35: Fox = 185, Tanaka = 183, Gulati (women) = 175, Nes = 189
- Age 45: Fox = 175, Tanaka = 176, Gulati (women) = 166, Nes = 182
- Age 55: Fox = 165, Tanaka = 169, Gulati (women) = 158, Nes = 176
- Age 65: Fox = 155, Tanaka = 162, Gulati (women) = 149, Nes = 169
The spread between formulas gets wider with age. At 25, the range is about 11 bpm. At 65, it’s 20. This is one reason older adults in particular benefit from knowing which formula to use, or from measuring their max heart rate directly.
Why Max Heart Rate Drops With Age
Your heart has a built-in pacemaker called the sinoatrial node, a cluster of specialized cells that generates the electrical impulse for each heartbeat. As you age, these cells physically enlarge and become less efficient. Research published in the Proceedings of the National Academy of Sciences found that the individual pacemaker cells in older hearts fire more slowly, not because of reduced fitness, but because of structural changes in the cells themselves.
Specifically, the electrical currents that drive each heartbeat cycle become weaker as cells grow larger. The current has to cover more cell surface, which dilutes its strength. The timing of the electrical reset between beats also slows down. This decline is intrinsic to the heart tissue and happens even when you block the nervous system’s influence on heart rate. It’s the reason max heart rate decreases at a roughly predictable rate of 0.6 to 1 beat per minute for each year of age, regardless of how active you are. Exercise doesn’t change your max heart rate, though it does improve how efficiently your heart works at every rate below the max.
How to Use Your Max Heart Rate
Once you have your estimated max, you can calculate training zones. The American Heart Association recommends these ranges:
- Moderate intensity: 50% to 70% of your max heart rate
- Vigorous intensity: 70% to 85% of your max heart rate
For a 45-year-old using the Tanaka formula (max of 176), moderate exercise falls between 88 and 123 bpm, and vigorous exercise between 123 and 150 bpm. These zones help you gauge effort during cardio workouts, especially if you use a chest strap or wrist-based heart rate monitor.
When Formulas Don’t Apply
Beta-blockers and certain other heart medications directly suppress heart rate, making all age-based formulas unreliable. Beta-blockers typically lower resting heart rate by about 10 beats per minute, and they also blunt the normal rise in heart rate during exercise. One rough adjustment is to subtract the same amount the medication reduced your resting rate from your predicted max, but this doesn’t fully account for how the drug limits heart rate during exertion. If you take any medication that affects heart rate, a formula-based target won’t reflect your actual ceiling.
The gold standard for measuring true max heart rate is a graded exercise test, usually performed on a treadmill in a clinical or sports science lab. The intensity increases in stages while your heart rate and oxygen consumption are monitored. This gives a precise, measured number rather than an estimate. It’s the method used in the studies that produced these formulas in the first place, and it’s the only way to know your actual max rather than a population average.
Which Formula Should You Use
For most men, the Tanaka formula (208 – 0.7 × age) is a solid starting point. For women, the Gulati formula (206 – 0.88 × age) accounts for sex-based differences that the standard formulas miss entirely. The classic 220-minus-age works in a pinch but drifts furthest from reality at younger and older ages. Whichever formula you choose, treat the result as a reasonable estimate, not a precise measurement. Individual variation of 10 to 12 bpm above or below the prediction is completely normal, even among healthy people of the same age and sex.