Maximum heart rate for runners often gets reduced to one very familiar equation: 220 minus your age. If you’re 40, that gives you an estimated maximum heart rate of 180 beats per minute, and many watches and training platforms can then use that number to help calculate your heart-rate zones.
It’s simple, but it can also be quite wrong for an individual runner.
Maximum heart rate does tend to decrease with age, which is why age appears in prediction equations in the first place. The difficulty is that runners of exactly the same age can have very different maximum heart rates. An equation based on population averages can give us a reasonable estimate for a group of people without accurately predicting the person standing in front of us.
That becomes important when your estimated maximum heart rate is being used to guide training. If the starting number is off by 10 or 15 beats per minute, percentage-based training zones calculated from it can be off too.
Before we get into it, I have to add some context to the image above. I was rushing through the shower after teaching a yoga class and forgot to stop my watch. The quick scrubbing paired with soap getting behind my watch resulted in a false reading of 229bpm ha! Perhaps a good argument for chest strap vs wrist based monitors..
What Is Maximum Heart Rate?
Maximum heart rate, usually written as HRmax, is the highest heart rate you can achieve during maximal exercise.
As running intensity increases, your muscles require more oxygen, and cardiac output rises to help meet that demand. Heart rate generally increases alongside the workload until you reach the highest rate your heart can achieve during that effort.
HRmax is influenced strongly by age and individual physiology, it isn’t a measure of how fit you are. And having a higher maximum heart rate than another runner doesn’t mean you’re in better shape.
Two 40-year-old runners could have measured maximum heart rates of 175 and 195 bpm, with both values being completely normal for those individuals. Their fitness is better assessed by factors such as running performance, VO₂max, running economy, and what intensities they can sustain relative to their own physiology.
Where Did 220 Minus Age Come From?
It’s commonly associated with Fox and colleagues in the early 1970s. Although the history behind it is less robust than you might expect for such a widely used formula.
The 220-minus-age equation became widely used despite never being formally validated as an individualized prediction method. Later reviews of its origin suggest it came from an approximate relationship observed across previously published data, rather than from a dedicated study designed to develop and validate the equation. The underlying observation was reasonable. Maximum heart rate generally decreases as we get older. Problems arise when that broad relationship is treated as a precise calculation of an individual runner’s HRmax.
For some people, 220 minus age will land fairly close. For others, the difference can be substantial.
How Accurate Are Age-Predicted Maximum Heart Rate Formulas?
There are better-researched equations than 220 minus age, but no age-based formula can precisely predict HRmax for every runner.
One of the most widely used alternatives is the Tanaka equation:
HRmax = 208 − (0.7 × age)
Tanaka and colleagues developed this equation using data from 351 studies involving 18,712 participants, then cross-validated it in a separate laboratory sample of 514 healthy adults.
Research in women has also produced the Gulati equation:
HRmax = 206 − (0.88 × age)
This equation came from exercise testing in 5,437 asymptomatic women.
For a 38-year-old woman, the three formulas give:
| Equation | Predicted HRmax |
|---|---|
| Fox | 182 |
| Tanaka | 181 |
| Gulati | 173 |
That’s already a nine-beat difference between prediction methods, and none of them has actually measured the runner’s maximum heart rate.
A 2020 study by Shookster and colleagues compared measured HRmax from graded treadmill tests with nine commonly used age-prediction equations, including Fox, Tanaka, and Gulati. Although the Fox equation performed relatively well at the group level in that sample, all nine equations showed wide limits of agreement with measured HRmax. In practical terms, none was consistently accurate enough to predict an individual person’s maximum heart rate.
Research in recreational marathon runners has also shown differences between predicted and measured HRmax. In that study, both the Fox and Tanaka equations overestimated measured HRmax by around 5 bpm on average in women, while the pattern was different in men.
More recent research continues to show the same broader issue. In a 2026 study of 4,375 endurance athletes, both the Fox and Tanaka equations underestimated self-reported field HRmax by around 5 to 6 bpm on average. The individual differences were much wider, with the limits of agreement extending well above and below those averages.
This is why average error can be misleading. An equation can perform reasonably well across a large group while still giving you a poor estimate of your own HRmax.
Why an Incorrect Maximum Heart Rate Can Affect Your Training Zones
Many watches and training platforms use maximum heart rate as one input when calculating heart-rate zones. If your HRmax is estimated incorrectly, the zones built from percentages of that value can shift with it.
For example, imagine your watch estimates your maximum heart rate at 180 bpm, while your measured maximum is actually 195 bpm.
At 70% of HRmax, those values would give you:
- 126 bpm using an HRmax of 180
- approximately 137 bpm using an HRmax of 195
That’s an 11-beat difference.
This can help explain why some runners find that their watch-generated zones don’t match what they experience during training. A supposedly easy zone may force them to run unusually slowly despite comfortable breathing and a low RPE. Another runner may find their calculated zones are too high.
Maximum heart rate is only one part of the equation. Different platforms also use different zone models, and some rely on heart-rate reserve, lactate threshold, or other metrics instead of simple percentages of HRmax.
Physiological thresholds add another layer of information. Two runners with the same HRmax can have their aerobic and threshold intensities at different percentages of that maximum. This is one reason individualized thresholds can be more informative for training prescription.
If you want to go deeper into that side of heart-rate training, you might like to read Heart Rate Training for Runners: How to Actually Use Your Zones.
Can Your Running Watch Find Your Maximum Heart Rate?
Running watches can provide good information about your highest recorded heart rates, particularly if you regularly race or complete hard workouts. Some devices can also update your estimated HRmax automatically based on recorded exercise data.
The important question is where the number came from.
A value calculated from your age is still a prediction. A high heart rate repeatedly recorded during genuinely hard efforts gives you more individualized information. Especially when the data comes from a reliable chest strap.
One isolated spike deserves more caution. Wrist-based optical monitors can occasionally produce erroneous readings or lock onto running cadence, and the highest heart rate reached in a normal workout may still be below your true maximum.
Looking at repeated hard efforts and the context around the data gives you a better picture than accepting one watch-generated number without question.
Can Runners Measure Maximum Heart Rate in the Field?
If you’re a healthy, experienced runner who is comfortable with maximal exercise, a field test can give you a much better estimate of your maximum heart rate than an age-based formula.
One option is the running field test described by Roy Benson and Declan Connolly. You’ll need a heart-rate monitor, preferably a chest strap if you have one, and either a 400 m running track or a gradual incline approximately 400 to 600 m long.
After a thorough warm-up:
- Run one 400 m lap, or the full incline, at a very hard effort.
- Record your heart rate at the end of the effort.
- Walk or jog easily for two minutes.
- Repeat the hard effort, followed by another two-minute active recovery.
- Complete a third hard effort and record your heart rate again. The highest value reached near the end of this repetition should give you a reasonable field estimate of HRmax.
- If you feel you still had more to give, you can complete a fourth effort after another two-minute recovery.
Once you’ve finished, keep walking or jogging for several minutes rather than stopping abruptly.
The quality of the result depends on actually reaching a maximal effort, which is one of the limitations of field testing. Your legs, pacing, motivation, terrain, weather, and heart-rate monitor can all influence the number you record. A repeated high value from a well-executed test is still far more individualized than simply assuming your HRmax is 220 minus your age.
I’d only use this type of test if you’re accustomed to hard running and have no reason to avoid maximal exercise. If you have cardiovascular symptoms, relevant medical conditions, take medications that affect heart rate, or have been advised to limit high-intensity exercise, speak with your physician before trying it.
What Does VO₂ Max Testing Add?
During a VO₂ max test, exercise intensity progressively increases while we measure respiratory gases, heart rate, and your physiological response to the workload.
If maximal effort is achieved, we can measure your HRmax rather than relying on an age-predicted equation. More importantly for training, the test also allows us to identify your ventilatory thresholds and the heart rates and paces associated with them.
Those thresholds help show where meaningful changes in your physiology occur as intensity increases. This gives us more information for setting individualized training zones than taking a predicted maximum heart rate and dividing it into generic percentages.
For example, two runners could both have a HRmax of 185 bpm, while reaching their ventilatory thresholds at different heart rates and running speeds. Giving them identical percentage-based zones would miss that individual variation.
That’s why I’m much more interested in understanding the full physiological picture than getting overly attached to one maximum heart-rate number. But then again, I am a physiology nerd.
Does Maximum Heart Rate Tell You How Fit You Are?
Your HRmax isn’t a fitness score.
Endurance training can improve the amount of work you can perform at submaximal heart rates, increase VO₂ max, shift your thresholds, and improve running performance without increasing your maximum heart rate.
A runner who used to run 6:00/km at 150 bpm and can now run 5:30/km at the same heart rate has made a meaningful fitness improvement, even if her HRmax hasn’t changed.
Maximum heart rate gives us a reference point, but what you can do below that maximum often tells us far more about your running fitness.
The Bottom Line on Maximum Heart Rate for Runners
Age based formulas can give runners a rough estimate of maximum heart rate, and that may be enough when you simply need a starting point. The limitation is assuming the estimate represents your individual physiology.
The familiar 220-minus age formula has a weak historical foundation, while equations such as Tanaka and Gulati were developed from much stronger datasets. Even those better-researched formulas still show meaningful individual prediction error.
If your estimated HRmax fits reasonably well with your training, and heart rate is only one of several tools you use to guide intensity, there may be no need to chase a more precise number.
When your watch-generated zones feel consistently wrong, you want more individualized training targets, or you’re preparing for a specific performance goal, measuring HRmax and your physiological thresholds can provide much better information than another age-based formula.
Key Takeaways
- Maximum heart rate, or HRmax, is the highest heart rate you can achieve during maximal exercise.
- HRmax generally decreases with age, but runners of the same age can have very different maximum heart rates.
- The 220-minus-age equation wasn’t developed from a dedicated validation study.
- The Tanaka and Gulati equations have stronger research foundations, but they still estimate HRmax rather than measure it.
- Age-based prediction equations can be reasonably accurate across groups while producing substantial error for an individual runner.
- An inaccurate HRmax can affect training zones calculated as percentages of maximum heart rate.
- Watch data from repeated hard efforts can provide individualized information. Although one unusually high reading shouldn’t automatically be assumed to represent HRmax.
- Field testing can assess HRmax in appropriate runners, while laboratory testing provides additional information about ventilatory thresholds and training intensity.
- HRmax isn’t a measure of running fitness.
- VO₂ max testing can measure maximum heart rate and identify physiological thresholds for more individualized heart-rate and pace zones.
Want More Accurate Heart-Rate Zones?
If your watch-generated zones don’t match how your running feels, the maximum heart rate they’re based on may be part of the problem. If you’re local to Vancouver, I offer VO₂ max testing in Port Moody. Testing measures your VO₂ max, maximum heart rate, and ventilatory thresholds, allowing us to establish individualized heart-rate and pace zones based on your physiology
Frequently Asked Questions About Maximum Heart Rate for Runners
The 220-minus age formula provides a rough population estimate of maximum heart rate, but individual error can be substantial. Some runners will fall close to the prediction, while others may be more than 10 beats per minute above or below it.
The Tanaka equation, 208 − (0.7 × age), has a stronger research basis than 220 minus age. The Gulati equation, 206 − (0.88 × age), was developed specifically in women. Both are still prediction equations, so neither can determine an individual runner’s exact maximum heart rate.
There isn’t one maximum heart rate that applies to every 40-year-old runner. Age-predicted equations produce estimates around 180 bpm, but measured HRmax can be considerably higher or lower depending on the individual.
No. Maximum heart rate is strongly influenced by age and individual physiology. Running fitness is better assessed using measures such as performance, VO₂ max, physiological thresholds, and pace at a given submaximal heart rate.
A running watch can record high heart rates during races and hard workouts, and some devices use exercise data to update estimated HRmax. Repeated high values from genuinely hard efforts are more informative than a single isolated reading, particularly when heart rate is measured with a reliable chest strap.
Healthy, experienced runners who are accustomed to high-intensity exercise can use appropriately designed maximal field testing to assess HRmax. Maximal exercise isn’t appropriate for everyone, so runners with cardiovascular symptoms, relevant medical conditions, or medications affecting heart rate may need medical guidance first.
Yes. During maximal graded exercise testing, heart rate is recorded as workload progressively increases. VO₂ max testing can also identify ventilatory thresholds and the heart rates and paces associated with them, providing more individualized information for training zones.
References
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
Benson, R., & Connolly, D. (2020). Heart rate training (2nd ed.). Human Kinetics.
Boulay, P., Ghachem, A., Poirier, P., Sigal, R. J., & Kenny, G. P. (2025). Assessment of maximum heart rate prediction equations in adults at low and high risk of cardiovascular disease. Medicine & Science in Sports & Exercise, 57(1), 60–69. https://doi.org/10.1249/MSS.0000000000003540
Gulati, M., Shaw, L. J., Thisted, R. A., Black, H. R., Bairey Merz, C. N., & Arnsdorf, M. F. (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
Nikolaidis, P. T., Rosemann, T., & Knechtle, B. (2018). Age-Predicted Maximal Heart Rate in Recreational Marathon Runners: A Cross-Sectional Study on Fox’s and Tanaka’s Equations. Frontiers in physiology, 9, 226. https://doi.org/10.3389/fphys.2018.00226
Shookster, D., Lindsey, B., Cortes, N., & Martin, J. R. (2020). Accuracy of commonly used age-predicted maximal heart rate equations. International Journal of Exercise Science, 13(7), 1242–1250. https://doi.org/10.70252/XFSJ6815
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. https://doi.org/10.1016/s0735-1097(00)01054-8
