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Predicted maximum heart rate and chronotropic index

Calculates predicted maximum heart rate, percentage achieved during exercise and chronotropic index, used to identify chronotropic incompetence.

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Check the population, units and version. The result shows the formula or classification; it does not make an automatic treatment decision.

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Method · Limits of application

Tanaka 2001: 208−0.7 age; classic 220−age; heart-rate-reserve chronotropic index Brubaker 2011

The Tanaka 2001 equation estimates maximum heart rate in healthy adults. Executing it with a pediatric age demonstrates only the mathematical operation, without evidence of clinical applicability in that population. Predicted heart rate is not the individually measured maximum; diagnosis of chronotropic incompetence, medication use and exercise protocols depend on their own assessment and sources.

Conditions of use

Check the population, units, inclusion and exclusion criteria, and version in the original source. A result alone does not establish a diagnosis, discharge decision or prescription.

Documented parameters

Age · years
Resting heart rate · bpm
Peak exercise heart rate · bpm

2/2 reference cases checked. Numerical tests are not clinical validation.

Sources and documentation

Documented formula

Transcribed from the source or a recorded revision; this is not a clinical recommendation.

Maximum HR (classic): 220 − age
Maximum HR (Tanaka): 208 − 0.7 × age
% achieved: peak HR ÷ maximum HR × 100
Chronotropic index: (peak HR − resting HR) ÷ (maximum HR − resting HR)

References

Identifier: frequencia-cardiaca-maxima

Original clinical content: Brazilian Portuguese.

Method version

Tanaka 2001: 208−0.7 age; classic 220−age; heart-rate-reserve chronotropic index Brubaker 2011

frequencia-cardiaca-maxima@native-2026-10-05+a1b7041f1f79

Source for the active edition

The bibliographic edition identifies the source. By itself, it proves neither full conformity of the formula nor clinical approval.

Synthetic cases checked (2)

Synthetic cases for checking the implementation, with no patient data.

Case 1

reference-001

Inputs

Age: 50 years
Resting heart rate: 70 bpm
Peak exercise heart rate: 160 bpm

{
  "idade": 50,
  "fcrep": 70,
  "fcpico": 160
}

Expected result

{
  "classic": 170,
  "tanaka": 173,
  "ci": 0.9
}

Actual result

{
  "classic": 170,
  "tanaka": 173,
  "pct": 94.11764705882352,
  "ci": 0.9
}

Case 2

reference-002

Inputs

Age: 50 years
Resting heart rate: 70 bpm
Peak exercise heart rate: 140 bpm

{
  "idade": 50,
  "fcrep": 70,
  "fcpico": 140
}

Expected result

{
  "level": "high"
}

Actual result

{
  "classic": 170,
  "tanaka": 173,
  "pct": 82.35294117647058,
  "ci": 0.7
}

Code and reproducibility

This tool’s code on GitHub

Download code and tests

Sources, version and reproduction instructions

README

Local installation

Code license: Apache-2.0

Guidelines and conditions

This repository’s license applies to the code. Third-party instruments, questionnaires, data and models remain subject to their owners’ conditions.

The code tests are technical checks. Clinical approval and professional translation review are recorded separately.

Relationship with cancer research

General context — relationship to be defined

A resource for general clinical contexts. This edition does not assign a specific oncological relationship; selecting it for a study requires a justified question, population and purpose.