Heart rate calculator
The 220-minus-age rule was an informal approximation that reached print in the 1970s and stayed. Tanaka and colleagues pooled 351 studies covering 18,712 people, fitted 208 − 0.7 × age, then cross-validated it on 514 subjects in the laboratory and got 209 − 0.7 × age. Both give the same slope, and it is gentler than the older rule's slope of 1.0. The two lines cross at exactly 40; below that 220-minus-age reads high, and above it reads low by a growing margin. Neither is a substitute for a measured maximum.
Predicted maximum heart rate varies by about ten beats either side even for people of the same age. Anyone with a heart condition, or starting hard exercise after a long break, should speak to a doctor first.
The Tanaka formula puts maximum heart rate at 208 − 0.7 × age, so a 35-year-old is 183.5 bpm, which the panel rounds to 184. With a resting rate, the Karvonen method sets zones as a percentage of heart rate reserve: maximum minus resting, which is more accurate than percentages of maximum alone.
How to find your training zones
Tanaka's 2001 paper is worth reading for what it rules out as much as what it establishes. Across 18,712 subjects the relationship between age and maximum heart rate was strong, with a correlation of −0.90, and the regression line did not differ between men and women. Nor was it shifted by wide variations in habitual physical activity. Fitness does many things; raising your maximum heart rate is not one of them. A second study, Gellish and colleagues in 2007, tracked 132 individuals through 908 maximal exercise tests over 25 years and arrived at 207 − 0.7 × age, which is the same slope from a longitudinal design rather than a cross-sectional one.
None of that makes the prediction good for a person. It is a population line with real scatter around it, so two 40-year-olds can differ by well over ten beats while both being entirely normal. A genuine maximum from a graded exercise test, or from the highest figure your monitor has recorded during an all-out effort, beats any equation on this page. The formula is for people who have no such number yet.
Entering a resting rate switches the zones from percentages of maximum to percentages of heart rate reserve, which is maximum minus resting. This is the Karvonen method, and it is the better one because it accounts for where your usable range actually starts. A fit person with a resting rate of 45 has a much wider reserve than someone at 75 with the same maximum, and percentage-of-maximum zones would hand them identical targets.
Of the five zones, Zone 2 is the one to understand. It is the conversational aerobic range, roughly 60 to 70 per cent of reserve here, and it is where the aerobic base is built. Recreational athletes tend to accumulate their volume in Zone 3 instead: hard enough to fatigue, not hard enough to force much adaptation, and tiring enough to cap the week's total. The polarised model most endurance coaching now uses puts around eighty per cent of training below the first threshold and the remainder genuinely hard, with little in the middle.
What people use it for
- Setting zones on a watch or bike computer
- Understanding what Zone 2 training means in beats
- Checking a prescribed target heart rate
- Comparing Karvonen reserve zones against percentage-of-max zones
- Seeing how far 220-minus-age is from Tanaka at your age
Questions
About 208 − 0.7 × your age. For a 55-year-old that is 170 bpm against 165 from the older 220 − age rule. The two lines cross at exactly 40, where both give 180.
A 2001 meta-analysis of 351 studies covering 18,712 people, cross-validated in a laboratory sample of 514, which returned 209 − 0.7 × age. A separate longitudinal study in 2007 following 132 people over 25 years landed on 207 − 0.7 × age.
It has no research origin, and its slope is too steep. Because it falls a full beat per year rather than 0.7, it increasingly underestimates maximum heart rate in older adults, which understates the effort a prescribed intensity actually represents.
No. Tanaka found the age relationship was not influenced by wide variations in habitual physical activity, and it was the same line for men and women. Training changes what you can do at a given heart rate, not the ceiling itself.
Because it starts counting from your resting rate rather than from zero. Two people with the same maximum and different resting rates have different usable ranges, and reserve zones reflect that.
The conversational aerobic zone, roughly 60 to 70 per cent of reserve. It builds the aerobic base and should carry most of your training volume.
Lying down, first thing in the morning, before getting up, averaged over several days. A single reading after coffee is not it, and the Karvonen zones are only as good as this number.
No. Maximum heart rate is largely genetic and declines with age. It says nothing about fitness or performance.