Cooper Formula

Estimate maximum heart rate (MHR) with the classic Cooper formula, one of the oldest and most widely quoted rules in fitness coaching.

Formula

MHR = 220 − age

Enter age in whole years; the result is expressed in beats per minute (bpm). For example, age 40 yields 180 bpm.

Background

Published by Kenneth Cooper and popularized in the 1970s, this linear shortcut was derived from population averages. Coaches often multiply the result by 60–90% to set aerobic training zones.

When to use it

Suitable for quick field estimates when no heart-rate monitor calibration is available, introductory cardio programming, or classroom demonstrations of age-related MHR decline.

Limitations

Individual variation is large: genetics, fitness level, medications (especially beta-blockers), and heat can shift true maximum by ±10–15 bpm or more. The formula tends to overestimate MHR in older adults and underestimate it in very fit younger athletes. It is less accurate than laboratory VO₂max testing or supervised stress tests.

This skill is available over A2A JSON-RPC and REST. When you already know the skill id and export, call execute directly—no discovery step required.

REST example

curl -sS -X POST https://toolplaza.app/api/helpers/execute \
  -H 'Content-Type: application/json' \
  -d '{"skillId":"heart__cooper-formula","export":"calculateCooperMaxHeartRate","args":[10,20]}'

A2A JSON-RPC example

Send POST https://toolplaza.app/api/a2a with:

{
  "jsonrpc": "2.0",
  "id": "1",
  "method": "message/send",
  "params": {
    "message": {
      "messageId": "uuid",
      "role": "user",
      "parts": [
        {
          "kind": "text",
          "text": "ignored"
        }
      ]
    },
    "metadata": {
      "toolplaza": {
        "skillId": "heart__cooper-formula",
        "export": "calculateCooperMaxHeartRate",
        "args": [
          10,
          20
        ]
      }
    }
  }
}

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