ForHosting KIT · Developer Utilities

Heart Rate Recovery Ratio Calculator

The heart rate recovery ratio compares your peak heart rate during exercise with a heart rate measured later in the recovery period.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

Enter both readings in beats per minute, and the calculator divides the peak value by the recovery value. The result is a compact, repeatable way to compare paired readings from the same exercise protocol. It does not diagnose fitness, illness, or cardiovascular health, because timing, activity, medication, temperature, posture, and measurement method can all influence the readings.

How to use it

Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.

Check your inputs

Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.

Use it again or automate it

Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.

What you can do with it

Get an answer now

Enter one set of values and see the result without building a spreadsheet or script.

Compare scenarios

Change one value at a time and rerun the calculation to understand what affects the result.

Automate repeated work

Use the API when the same calculation needs to run inside your product or workflow.

FAQ

What formula does the calculator use?

It divides peak heart rate by recovery heart rate and rounds the ratio to six decimal places.

What units should I enter?

Enter both readings in beats per minute. Because the units cancel during division, the resulting ratio has no unit.

Is this the same as heart rate recovery in bpm?

No. A recovery difference subtracts the later reading from the peak, while this capability divides the peak by the later reading.

Does a higher ratio always mean better fitness?

No. Timing, exercise protocol, posture, medication, environment, and measurement quality affect the readings, so the ratio is not a standalone clinical interpretation.

What happens when a required reading is missing?

The request returns an invalid_input error identifying the missing required field instead of producing a result.

How much does an API calculation cost?

Each successful API request costs $0.002; the same deterministic calculation is also available in the browser.

For developers — API access

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

API endpoint

POSThttps://api.kit.forhosting.com/health/heart-rate-recovery-ratio

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

Call it from your stack

curl -X POST https://api.kit.forhosting.com/health/heart-rate-recovery-ratio \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"peak_heart_rate":180,"recovery_heart_rate":120}'

const res = await fetch("https://api.kit.forhosting.com/health/heart-rate-recovery-ratio", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "peak_heart_rate": 180,
    "recovery_heart_rate": 120
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/health/heart-rate-recovery-ratio",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "peak_heart_rate": 180,
    "recovery_heart_rate": 120
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/heart-rate-recovery-ratio", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"peak_heart_rate":180,"recovery_heart_rate":120}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"peak_heart_rate":180,"recovery_heart_rate":120}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/heart-rate-recovery-ratio", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "peak_heart_rate": 180,
  "recovery_heart_rate": 120
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "health.heart_rate_recovery_ratio",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Pricing

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Errors

HTTP	Code	Meaning
`401`	`unauthorized`	Missing or invalid API key.
`402`	`insufficient_balance`	Your balance doesn't cover the task price.
`404`	`unknown_type`	That task type doesn't exist.
`429`	`rate_limited`	Too many requests. Use the webhook instead of polling.

Read the full KIT documentation →