ForHosting KIT · Developer Utilities

VO2 max Bruce treadmill protocol calculator

The Bruce treadmill protocol is a graded exercise test that raises speed and grade every three minutes until the subject stops.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

Total time on the belt is a widely used proxy for cardiorespiratory fitness: exercise physiologists convert that duration into estimated maximal oxygen uptake with published sex-specific regressions. This capability accepts total Bruce time in decimal minutes or a clock string, together with sex, applies the Foster cubic for men or the linear women formula, and returns structured JSON with VO2 max in millilitres per kilogram per minute, stage bookkeeping, and the formula used. The path is pure arithmetic with no network and no random seed, so clinics, sports labs, PE courses, and prepaid API clients get identical results every time. Non-positive or invalid time is rejected as invalid input because a zero or negative duration cannot describe a completed Bruce trial. The browser widget runs free on your device; the prepaid API charges $0.002 per successful item when servers and SDKs need the same contract.

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 is the Bruce VO2 max formula?

For men, VO2 max in ml/kg/min is 14.8 − 1.379·T + 0.451·T² − 0.012·T³ (Foster cubic). For women, VO2 max is 4.38·T − 3.9. T is total Bruce treadmill time in minutes. This calculator applies the matching formula from the sex field.

What happens if time is zero or negative?

The request fails with invalid_input. Time must be a positive value describing how long you completed on the Bruce protocol; non-positive time is rejected and not charged.

Do I need sex as well as time?

Yes. Sex selects the sex-specific regression (male Foster cubic vs female linear). Provide male or female; short codes m/f and 1/0 are also accepted by the engine.

Is the VO2 max Bruce treadmill protocol calculator free?

The browser tool runs free on your device. API calls use prepaid KIT balance at $0.002 per successful item; validation failures are not charged.

Is this the same as laboratory VO2 max?

No. This is a field estimate from published Bruce time regressions, not gas-exchange VO2 peak from a metabolic cart. Use it for practical aerobic screening and education, not clinical diagnosis alone.

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/vo2max-bruce

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/vo2max-bruce \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"time":12.5,"sex":"male"}'

const res = await fetch("https://api.kit.forhosting.com/health/vo2max-bruce", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "time": 12.5,
    "sex": "male"
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/health/vo2max-bruce",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "time": 12.5,
    "sex": "male"
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/vo2max-bruce", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"time":12.5,"sex":"male"}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"time":12.5,"sex":"male"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/vo2max-bruce", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "time": 12.5,
  "sex": "male"
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "health.vo2max_bruce",
  "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 →