Your maximum heart rate is the fastest your heart can beat during all-out effort, and the simplest way to estimate it is by subtracting your age from 220. A 40-year-old, for example, gets an estimated max of 180 beats per minute (bpm). But that formula has a margin of error of 10 to 12 bpm in either direction, which means your true max could be anywhere in a 24-beat range. For something more accurate, you have better formulas and a straightforward field test you can do on your own.
The 220-Minus-Age Formula and Its Limits
The “220 minus age” equation dates back to 1971, when researchers Fox and Haskell compiled data showing that max heart rate drops with age. It was never meant to be precise. It was a rough approximation based on observed trends, and it carries a standard deviation of 10 to 12 bpm. That means about one-third of people will fall outside even that wide range.
In practical terms, if you’re 30 and the formula gives you 190 bpm, your actual max could realistically be anywhere from 178 to 202. That gap matters if you’re using heart rate zones to guide your training. Basing your zones on a number that’s 10 beats too high means your “easy” runs aren’t easy enough, and your threshold work feels impossible to sustain.
A Better Formula for Women
The standard formula was built on studies of men, and it tends to overestimate max heart rate in women. Research from the Women’s Health Research Institute led to a sex-specific formula: 206 minus 88% of your age. For a 40-year-old woman, that gives 206 minus 35.2, or about 171 bpm, compared to 180 from the old formula.
That nine-beat difference has real consequences. When clinicians used the standard formula for women, they were more likely to flag a worse prognosis than actually existed. Women have different physiological responses to exercise, including differences in exercise capacity, and a formula designed around male data simply doesn’t capture that. If you’re a woman using heart rate zones, this adjusted formula is a better starting point.
How Max Heart Rate Changes With Age
Max heart rate does decline as you get older, but the rate of decline is more gradual than most people assume. Longitudinal data published in Circulation found that max heart rate drops about 4% to 6% per decade in both men and women. For someone with a true max of 190 at age 30, that works out to roughly 7 to 11 fewer beats per decade.
The decline accelerates slightly with age and appears a bit steeper in women. But here’s what’s important: the drop in max heart rate is only a fraction of the overall decline in aerobic fitness. Your body’s ability to extract and use oxygen per heartbeat declines two to three times faster than your heart rate ceiling. So while your max heart rate is lower at 60 than it was at 30, maintaining cardiovascular fitness through training preserves far more of your capacity than that number alone suggests.
How to Test Your Max Heart Rate Directly
Formulas give you estimates. If you want your actual number, you need to push your heart rate to its ceiling under controlled conditions. The most accessible method is a hill repeat test, and the protocol is straightforward.
Find a hill steep enough to force hard effort but not so steep you can’t maintain a running or cycling rhythm. After a thorough warmup of at least 10 to 15 minutes, run or ride up the hill at a hard, sustained effort for four to six minutes. You should be deep into your upper effort zones. When you feel like you can’t maintain the pace much longer, put in a final all-out sprint. Check your heart rate monitor immediately at the top. That peak reading is your max heart rate.
A few things make this test more reliable. Do it when you’re rested, hydrated, and haven’t had caffeine recently. Repeat the effort two or three times in the same session with full recovery between intervals. Your highest reading across those efforts is your max. A single attempt often falls short because pacing yourself or stopping too early is natural when you’re suffering.
Who Should Skip the Self-Test
A max heart rate test is a maximum exertion effort, and it’s not appropriate for everyone. If you’re over 35 and new to exercise, get medical clearance first. You should also hold off if any of these apply to you: a doctor has told you that you have a heart condition, you experience chest pain during or outside of physical activity, you have episodes of dizziness or loss of consciousness, you take medication for blood pressure or a heart condition, or you have a bone or joint problem that intense activity could worsen.
During the test itself, stop immediately if you feel chest pain (especially pain radiating to your neck, jaw, arm, or between your shoulder blades), extreme breathlessness beyond what hard effort normally produces, or a sudden irregular heartbeat.
Your Heart Rate Monitor Matters
The accuracy of your test depends partly on what you’re wearing. Chest strap monitors use electrical signals similar to a medical ECG and remain the gold standard for accuracy. Optical sensors, like those on wrist-based watches and armbands, use light to detect blood flow and work well at lower intensities. But during high-intensity intervals, optical sensors can drift.
Comparative testing found that an armband optical sensor overestimated heart rate by about 5 bpm during hard efforts compared to chest straps. The range of error was even wider on individual readings, with measurements swinging up to 9 bpm above or below the chest strap value. If you’re doing a max heart rate test and the whole point is capturing one precise peak number, a chest strap will give you more confidence in the result. Wrist sensors are fine for daily training but can blur the line between a true max and a sensor artifact at peak intensity.
Medications That Lower Your Ceiling
Beta blockers, commonly prescribed for high blood pressure, directly limit how fast your heart can beat. They work by blocking the signals that tell your heart to speed up, which means your heart rate won’t climb the way it normally would during exercise. If you take a beta blocker, neither a formula nor a field test will give you a useful “true” max heart rate. Your functional max while on the medication is lower than your physiological ceiling, and that’s the number that actually matters for setting training zones.
Other medications, including certain calcium channel blockers and some antiarrhythmic drugs, can also affect heart rate response. If you take any heart-related medication and want to train by heart rate, a supervised exercise test with your doctor’s input will give you far more useful numbers than any formula or self-test.
Putting Your Number to Use
Once you have a max heart rate, whether estimated or tested, you can set training zones as percentages of that number. Most zone systems break effort into five levels, from recovery (50% to 60% of max) up to maximum effort (90% to 100%). The zones in between cover easy aerobic work, tempo effort, and threshold training.
Keep in mind that your max heart rate is a fixed ceiling for your current age and condition. It doesn’t improve with training. What does improve is your efficiency at every heart rate below that ceiling. A well-trained runner might hold a pace at 150 bpm that would have required 170 bpm six months earlier. That shift is the real measure of fitness progress, not the max number itself.
If you used a formula, treat your zones as starting points and adjust based on how efforts actually feel. If your “easy” zone feels moderate, or your “threshold” zone feels impossible, your estimated max is probably off. Recalculating with a field test or a sex-specific formula can tighten things up considerably.