The most widely used formula for estimating maximum heart rate is 220 minus your age. If you’re 40, your estimated max is 180 beats per minute (bpm). It’s simple, memorable, and the default in most fitness apps and gym posters. But it’s also not particularly accurate for many people, and better alternatives exist.
The Traditional Formula: 220 Minus Age
This equation, often called the Fox formula, has been the standard since the 1970s. You subtract your age from 220 to get your predicted maximum heart rate. A 30-year-old gets 190 bpm; a 55-year-old gets 165 bpm.
The problem is that this formula was never rigorously validated. It tends to overestimate max heart rate in younger adults and underestimate it in older adults. Studies have found a standard deviation of 10 to 12 bpm, meaning your true max could easily be a dozen beats higher or lower than what the formula predicts. In practical terms, that’s enough to put you in the wrong training zone entirely.
A More Accurate Alternative: 208 Minus 0.7 × Age
A large meta-analysis published in the Journal of the American College of Cardiology proposed a revised formula: 208 minus 0.7 times your age. For a 40-year-old, that gives 180 bpm (the same as the traditional formula at that age), but the two equations diverge at younger and older ages. A 25-year-old gets 190.5 instead of 195, and a 65-year-old gets 162.5 instead of 155.
This revised equation better accounts for the fact that max heart rate doesn’t decline as steeply with age as the old formula assumes. It was developed from data on thousands of healthy adults and is particularly more reliable for people over 40, where the traditional formula most consistently falls short.
A Formula Designed for Women
Both of the equations above were derived primarily from male subjects. Research from the St. James Women Take Heart Project, published through the American Heart Association, found that the traditional formula overestimates max heart rate in women. Their data from over 5,000 asymptomatic women produced a female-specific formula: 206 minus 0.88 times your age.
For a 50-year-old woman, this gives 162 bpm instead of the 170 predicted by the traditional formula. That 8-beat difference matters. Using the male-derived formula, about 7% of women in the study appeared to have an abnormally low heart rate response during stress testing. With the female-specific formula, that number dropped to 3%. The mismatch likely contributes to the higher rate of inconclusive exercise stress tests in women compared to men.
Quick Reference by Age
- Age 25: Traditional = 195 | Revised = 190 | Women’s = 184
- Age 35: Traditional = 185 | Revised = 184 | Women’s = 175
- Age 45: Traditional = 175 | Revised = 177 | Women’s = 166
- Age 55: Traditional = 165 | Revised = 170 | Women’s = 158
- Age 65: Traditional = 155 | Revised = 163 | Women’s = 149
Notice how the traditional formula and the revised formula cross around age 40. Below that age, the traditional formula runs higher. Above it, the revised formula runs higher. The women’s formula consistently produces lower numbers at every age.
Why All Formulas Have Limits
No age-based equation can fully account for individual variation. The American College of Sports Medicine notes that even the best prediction formulas carry a margin of error of 3 to 12 bpm. Two 45-year-olds with similar fitness levels can have true max heart rates that differ by 20 beats or more.
Genetics play a significant role. Studies on twins and families estimate that roughly 20% to 35% of the variation in heart rate response to exercise is inherited. Your cardiovascular wiring, the balance of signals that speed up and slow down your heart, and even specific genes all influence where your personal ceiling sits. Fitness level matters too: years of endurance training shift your heart’s autonomic balance and can change how your heart rate responds to intense effort.
Medications are another major factor. Beta blockers, commonly prescribed for high blood pressure and heart conditions, directly lower both resting and exercise heart rate. If you take one, age-based formulas won’t apply to you in any meaningful way. One rough adjustment is to subtract the same number of beats per minute that the medication has reduced your resting heart rate (often around 10 bpm), but even that is an approximation. Your doctor or a supervised exercise test will give you a better target.
How to Use Max Heart Rate for Training
Most people look up their max heart rate because they want to set training zones. The simplest approach is to take a percentage of your estimated max: 60% to 70% for easy aerobic work, 70% to 80% for moderate effort, and 80% to 90% for high-intensity intervals.
A more personalized method factors in your resting heart rate. Called the Karvonen method, it works like this: subtract your resting heart rate from your max heart rate to get your “heart rate reserve.” Then multiply that reserve by your target percentage and add your resting heart rate back. For example, if your estimated max is 180 and your resting heart rate is 60, your reserve is 120. To train at 70% intensity, you’d calculate 120 × 0.70 + 60 = 144 bpm. This approach accounts for individual fitness because a lower resting heart rate (typical of fitter individuals) shifts all the zones upward.
Finding Your Actual Max Heart Rate
If you want precision rather than estimation, you need to measure your max heart rate directly. The gold standard is a graded exercise test, typically done on a treadmill or stationary bike in a clinical setting, where the intensity increases in stages until you can’t continue. These tests are supervised and often include ECG monitoring.
A less formal option is a field test: after a thorough warmup, do two or three all-out efforts lasting 2 to 3 minutes each (like running up a steep hill), with short recovery between them. The highest heart rate you hit on the last effort is a reasonable approximation of your true max. A chest strap heart rate monitor is far more reliable than a wrist-based sensor for capturing these peak readings.
For most recreational exercisers, the revised formula (208 minus 0.7 × age) paired with attention to how you actually feel during workouts is a solid starting point. If your training feels too easy or impossibly hard at the “right” heart rate, your true max likely differs from the prediction, and adjusting based on real-world experience is perfectly reasonable.