Concept
Maximum heart rate
The highest heart rate a person can reach during maximal effort. It is individual, changes little with training, and cannot be graded as a performance score.
Why it matters
Many zone systems use maximum heart rate as their main input. An inaccurate maximum shifts every percentage-based boundary.
Why age formulas miss individuals
Equations such as 220 minus age summarize population averages. Individual values can sit well above or below the estimate without indicating better or worse fitness.
How to improve the estimate
Reliable readings from hard races or workouts may provide a practical observed value. A formal or field maximum test is optional and should only be attempted when appropriate.
Begin with an estimate, compare it with believable hard-effort history, and update it only when repeated evidence supports the change.
A higher maximum heart rate does not mean a person is fitter, and reaching an age-predicted number is not a training goal.