What 220 Minus Your Age Gets Wrong About Max Heart Rate

A lot of treadmills have a small chart printed on the console, with your age down one side and a colored band of target heart rates across the middle. Most of those charts start from the same sum: 220 minus your age. It’s easy to remember, and it gets repeated so often that people treat it as a measurement.

For a 45-year-old it gives 175 beats a minute. The actual maximum of a given 45-year-old could just as easily be in the mid-160s or the mid-180s, and the formula has no way of telling which. That doesn’t matter much until you use the number to set training zones.

Where 220 Minus Age Came From

In 2002, the exercise physiologists Robert Robergs and Roberto Landwehr set out to find the source of the equation. They traced it to a 1971 paper by Fox and colleagues, who had gathered maximum heart rates from roughly a dozen earlier data sets and drawn a straight line through them by eye. Nobody had run a regression to produce it. The line happened to give a tidy, round number, and from there it found its way into textbooks and onto gym equipment.

Robergs, R.A. & Landwehr, R. (2002). “The surprising history of the ‘HRmax=220-age’ equation.” Journal of Exercise Physiology Online, 5(2), 1-10.

Better Formulas, Same Basic Limit

A more careful estimate had appeared the year before. Hirofumi Tanaka and colleagues pooled 351 studies covering about 18,700 people, then tested the result in their own lab on 514 adults. Their equation is 208 minus 0.7 times your age. At 40 it agrees exactly with the old formula (180). The two drift apart with age: at 60 Tanaka gives 166 where the old sum gives 160, and at 70 it’s 159 against 150. On average, then, 220 minus age underestimates the maximum of older people, and a chart built on it can tell a 65-year-old to hold back more than they need to.

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.

Gellish and colleagues took a different route in 2007. Instead of comparing different people at different ages, they used repeated tests on the same people as they got older. They arrived at almost the same line, 207 minus 0.7 times age, and even then the prediction was typically off by several beats either way.

Gellish, R.L. et al. (2007). “Longitudinal modeling of the relationship between age and maximal heart rate.” Medicine & Science in Sports & Exercise, 39(5), 822-829.

Whichever formula you pick, plenty of people land 10 or more beats above or below it. Age explains part of the spread, and genetics and fitness account for some of the rest. Some medicines move it too. Beta-blockers lower heart rate across the board, so if you take one, a formula built on people who didn’t won’t fit you.

Why a Few Beats Change Your Zones

Heart-rate zones are percentages of your maximum, which means any error in the maximum carries straight through. Say you’re 45 and your watch caps your easy zone at 70% of 175, about 122 beats a minute. If your real maximum is 187, that ceiling should be closer to 131. You could spend months jogging slower than you need to, or walking up every hill to keep the watch quiet. If your maximum is lower than the formula says, the error runs the other way, and sessions you meant to keep easy end up harder than planned.

Estimating Yours, or Skipping the Number

A field test gets you closer than any formula, but it involves running or riding very hard, so it’s only for people who are healthy and already training regularly. If you have a heart condition, take medication that affects your heart rate, are new to exercise, or have ever felt chest pain or faintness during effort, skip the test and ask your doctor what intensity is safe for you. For everyone else, it goes like this:

1. Wear a chest strap if you can. Wrist sensors are less reliable when your heart rate is climbing fast.
2. Warm up thoroughly, building from easy to moderately hard.
3. Find a steady hill (or raise the incline or resistance) and go as hard as you can for 2–3 minutes.
4. Recover with an easy walk or ride back down, then repeat the effort once or twice.
5. Take the highest reading from any of the efforts. If you’ve recently done a hard race or interval session with a strap on, the highest number from that works too.

You can also leave the number alone. The talk test needs no equipment: if you can speak in full sentences, you’re working easily, and if you can only get out a few words at a time, you’re working hard. How hard a session feels is a legitimate measure of intensity, and for a lot of people it’s all they need.

Lamplit’s workout log works on exactly that basis. You record the type of exercise, how long it lasted and how hard it felt (light, moderate or intense), and it’s free. Rating sessions by feel for a few weeks tells you how much of your training is actually easy, which is the question zones are trying to answer anyway. With Lamplit Pro, heart-rate data from your watch comes in automatically through Apple Health on iPhone or Health Connect on Android, if you’d like the numbers as well.

Log today’s workout in Lamplit and rate how hard it felt. It’s free.