Age-Based Max Heart Rate Formula vs. a Measured Max: Which Is More Accurate
A measured max heart rate (from an actual maximal or near-maximal effort test) is more accurate for a specific individual than any age-based formula, since formulas are population averages with substantial individual variation around them — the formula remains a reasonable, accessible starting point for anyone not ready or willing to undergo a genuine maximal effort test.
This is a genuine accuracy-versus-accessibility trade-off, not a case where one option is simply wrong — the right choice depends on training goals and willingness to undergo a maximal effort test.
Why measured max is more accurate
A genuine maximal effort test directly measures an individual's actual physiological max, sidestepping the population-average limitation of any formula — for someone training seriously with heart rate zones, this individual accuracy can meaningfully improve how well calculated training zones match actual intended effort levels.
Why a formula is still a reasonable default for most people
A maximal effort test requires significant exertion and carries some risk, particularly without medical supervision — for casual or general fitness training, a formula-based estimate is a reasonable, accessible, and safer starting point, even knowing it carries more individual uncertainty than a measured value.
A middle-ground approach
Starting with a formula-based estimate, then adjusting zones based on how training actually feels relative to perceived effort over time, gives a reasonable practical compromise for someone not pursuing a formal maximal test but who notices their formula-based zones don't quite match their felt experience of effort.