Heart Rate Zones Calculator: Max Heart Rate by Tanaka or 220 Minus Age, and Karvonen Zones

Fox: maximum heart rate = 220 - age. It is not the result of a study. It comes from a 1971 review by Fox, Naughton and Haskell, whose figure legend said the line defines a line not far from many of the data points, and a 2002 history of the formula found it was a superficial estimate from about 11 sources. Tanaka: maximum heart rate = 208 - 0.7 x age, from a 2001 meta-analysis of 351 studies and 18,712 people, checked in 514 healthy adults where the regression was 209 - 0.7 x age. The authors found no difference between men and women or by physical activity level, and that 220 - age underestimates maximum heart rate in older adults. Gulati: maximum heart rate = 206 - 0.88 x age, from 5,437 asymptomatic women with a mean age of 52, where the traditional male-based calculation overestimated the maximum for women. The Gulati equation is shown for women only.

All of these have a large error for any one person. The 2002 review put the standard error of estimate of 220 - age at 7 to 11 beats a minute and found that most age-based equations have errors above 10 beats a minute, so your real maximum can easily be 10 beats or more higher or lower than a formula says. A maximum measured in a supervised exercise test, or how hard the effort feels, is a better guide than any equation. You can type in a maximum you measured and the zones will use it.

The zones by percentage use the five-zone scheme used by fitness-device makers such as Polar: 50 to 60 percent of maximum is zone 1 (very light), 60 to 70 zone 2 (light), 70 to 80 zone 3 (moderate), 80 to 90 zone 4 (hard) and 90 to 100 zone 5 (maximum). In this tool each zone runs from its own starting beat to one beat below the next zone's start, and zone 5 ends at your maximum. Values are rounded half up to a whole beat. The scheme is a convention, not a medical classification.

The Karvonen method uses the heart rate reserve, the gap between your resting and maximum heart rate: target = resting + (maximum - resting) x intensity. The same percentages are applied to the reserve, so the zones sit higher than percent-of-maximum zones. For a maximum of 180 and a resting rate of 60 the reserve is 120, and 70 percent of the reserve is 60 + 84 = 144 beats a minute, while 70 percent of the maximum is 126. The method goes back to a 1957 study by Karvonen, Kentala and Mustala of the effects of training on heart rate.

To measure resting heart rate, find your pulse at the wrist or the side of the neck with two fingers and count the beats for 15 seconds and multiply by four, or for 30 seconds and multiply by two. The usual advice is to check when you get up in the morning. Mayo Clinic Care Network content gives a normal adult resting rate as 60 to 100 beats a minute, with very fit athletes closer to 40, and says to see a doctor if it is often above 100, or often below 60 when you are not a trained athlete, especially with fainting, dizziness or shortness of breath.