Two published answers, and they disagree
The CDC defines moderate intensity as 64 to 76% of maximum heart rate and vigorous intensity as 77 to 93%, citing the American College of Sports Medicine's Guidelines for Exercise Testing and Prescription. Its own worked examples are a 50-year-old at 109 to 129 bpm for moderate and a 35-year-old at 142 to 172 bpm for vigorous.
The American Heart Association publishes a different chart: moderate at 50 to 70% of maximum, vigorous at 70 to 85%, and an overall target zone of 50 to 85%. For a 40-year-old that is 90 to 153 bpm, against 115 to 167 bpm from the CDC bands. The calculator shows both rather than averaging them, because the two are answering slightly different questions. The ACSM bands classify exercise intensity for the physical activity guidelines. The AHA chart gives the general public a floor low enough to start from.
Why the maximum is 220 minus age here
Both bodies anchor their percentages to 220 minus age. That formula is the weakest of the published predictors: Tanaka's 208 minus 0.7 times age fits adults better, and any of them can miss an individual by 10 to 12 bpm. The calculator keeps 220 minus age anyway, because the bands were published against it and mixing a better estimator into someone else's percentages would produce numbers nobody has published.
The honest fix is a measured maximum. If you know yours from a hard effort, the heart rate zone calculator takes it directly and the bands stop depending on a population average. Below age 40 the age formula tends to overestimate your maximum, above 40 it tends to underestimate it, so the direction of the error is at least predictable.
Health bands are not training zones
Target heart rate answers a public-health question: how hard to move for 150 minutes a week of moderate activity, or 75 minutes of vigorous. Two bands are enough for that. Endurance training needs finer divisions, because the difference between easy, threshold and interval work is what a training plan is made of, and all three sit inside the vigorous band.
The talk test maps onto the two bands well. At moderate intensity you can talk but not sing. At vigorous intensity you can manage a few words before you need to breathe. Beta-blockers and some other medications lower heart rate and make every percentage target wrong, and both the CDC and the AHA say to ask a doctor for a corrected target in that case.
How to use a target heart rate
The bands are a range, not a single number to hold. The point is to know which side of moderate you are on, and to stop guessing.
- 1
Pick one convention and stay with it
Follow the ACSM/CDC bands if you are tracking against the physical activity guidelines, or the AHA zone if you are following its chart. Switching between them mid-week moves your targets by 10 to 25 bpm for no physiological reason.
- 2
Check with the talk test
Moderate: full sentences, no singing. Vigorous: a few words at a time. If the number and the talk test disagree, trust the talk test, because the number is built on an age estimate.
- 3
Count the minutes, not the beats
The guideline is 150 minutes of moderate or 75 minutes of vigorous activity a week, and vigorous minutes count double. Time in band is the metric, not peak heart rate.
- 4
Replace the estimate when you can
A measured maximum from a hard effort, or a maximum learned by a watch over months of hard sessions, beats 220 minus age. Enter it in the heart rate zone calculator and use those bands instead.
Target heart rate by age
The two conventions at every age, so you can see how far apart they sit and where your own row falls. Every value assumes 220 minus age as the maximum, which is why a measured maximum changes every number in the table.
| Age | Est. max | Moderate 64–76% | Vigorous 77–93% | AHA zone 50–85% |
|---|---|---|---|---|
| 20 | 200 | 128–152 | 154–186 | 100–170 |
| 25 | 195 | 125–148 | 150–181 | 98–166 |
| 30 | 190 | 122–144 | 146–177 | 95–162 |
| 35 | 185 | 118–141 | 142–172 | 93–157 |
| 40 | 180 | 115–137 | 139–167 | 90–153 |
| 45 | 175 | 112–133 | 135–163 | 88–149 |
| 50 | 170 | 109–129 | 131–158 | 85–145 |
| 55 | 165 | 106–125 | 127–153 | 83–140 |
| 60 | 160 | 102–122 | 123–149 | 80–136 |
| 65 | 155 | 99–118 | 119–144 | 78–132 |
| 70 | 150 | 96–114 | 116–140 | 75–128 |
| 75 | 145 | 93–110 | 112–135 | 73–123 |
| 80 | 140 | 90–106 | 108–130 | 70–119 |
Worked example
A 50-year-old, using the CDC's own example age:
| Estimated maximum (220 − 50) | 170 bpm |
| Moderate, ACSM/CDC (64 to 76%) | 109–129 bpm |
| Vigorous, ACSM/CDC (77 to 93%) | 131–158 bpm |
| AHA target zone (50 to 85%) | 85–145 bpm |
| Tanaka maximum (208 − 0.7 × 50) | 173 bpm |
The AHA floor sits 24 beats below the CDC floor at the same age. Neither is wrong; they were written for different readers. At 50 the two age formulas differ by only three beats, so the choice of convention matters more than the choice of maximum.
Frequently asked questions
What is my target heart rate by age?
Subtract your age from 220 for an estimated maximum, then take 64 to 76% of it for moderate exercise and 77 to 93% for vigorous, the ACSM/CDC bands. A 40-year-old gets 115 to 137 bpm moderate and 139 to 167 bpm vigorous. The American Heart Association's chart uses 50 to 85% of the same maximum, 90 to 153 bpm at 40.
Why do the CDC and the American Heart Association give different numbers?
They use different intensity classifications on the same 220-minus-age scale. The CDC follows ACSM, which puts moderate at 64 to 76% and vigorous at 77 to 93%. The AHA chart puts moderate at 50 to 70% and vigorous at 70 to 85%. Both are published as written; the calculator shows them side by side.
Is 220 minus age accurate?
Not for an individual. It misses by roughly 10 to 12 bpm either way, overestimating for younger adults and underestimating for older ones. Tanaka's 208 minus 0.7 times age fits better. The calculator keeps 220 minus age because that is the formula the published bands were built on.
What is a good target heart rate for weight loss?
There is no special weight-loss band. Total energy expenditure across the week decides fat loss, and harder sessions burn more per minute. Fat oxidation itself peaks near 74% of maximum, which sits in the moderate band; the fat burning zone calculator covers that separately.
Is target heart rate the same as a training zone?
No. Target heart rate is a two-band public-health measure of exercise intensity. Training zones divide the same scale into five or more bands so that easy, threshold and interval sessions can be told apart. If you train for a race, use the heart rate zone calculator instead.
Sources
- CDC, Target Heart Rate and Estimated Maximum Heart Rate. Moderate intensity 64–76% and vigorous intensity 77–93% of maximum heart rate, with maximum taken as 220 − age; worked examples for ages 50 and 35. Cites ACSM's Guidelines for Exercise Testing and Prescription, 10th ed. Link
- American Heart Association, Target Heart Rates Chart. Moderate 50–70%, vigorous 70–85%, target zone 50–85% of maximum heart rate (220 − age), tabulated by age from 20 to 70. Link
- Tanaka, Monahan & Seals (2001). Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology 37(1):153-156. HRmax = 208 − 0.7 × age. Link
- Garber et al. (2011), ACSM Position Stand. Quantity and quality of exercise for developing and maintaining fitness in apparently healthy adults. Medicine & Science in Sports & Exercise 43(7):1334-1359. Intensity classification: moderate 64–76% HRmax, vigorous 77–95% HRmax. Link
- How Every Watch Calculates Your Max Heart Rate (10 Brands Compared)Garmin uses Tanaka, COROS uses Gellish, Apple publishes nothing, Wahoo skips HRmax entirely. Ten brands, their formulas and zone models, in one table.
- How Fitbit Calculates Your Max Heart Rate (HRmax)Fitbit estimates HRmax with 220 − age, then personalises your zones using heart rate reserve. That second step is why its zones look wrong to runners.