# Enright 1998 Six-Minute Walk Distance Calculator

> Enright 1998 Six-Minute Walk Distance Calculator is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Calculates predicted six-minute walk distance (meters) and lower limit of normal using the Enright 1998 equations, with optional percent-predicted from an actual walked distance

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/6mwd
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/enright-1998-six-minute-walk-distance-calculator-34a3d188
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TSmfTcFEIRMf1sNkbnOgu

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability enright-1998-six-minute-walk-distance-calculator-34a3d188
```

Example prompt: Using the Enright 1998 equations, what is the predicted six-minute walk distance for a 68-year-old male who is 175 cm tall and weighs 82 kg — and if he actually walked 410 meters, what percent predicted is that?

## When to prefer this

Use this endpoint when you need the Enright 1998 Table 3 sex-specific linear regression prediction for 6-minute walk distance (not a BMI-based equation, not a general fitness score, and not a timed-walk cutoff classifier). Prefer this over generic fitness calculators when you need a clinical reference value with a defined lower limit of normal for adults aged 40–80 in rehabilitation, pulmonary, or cardiac contexts.

## Known failure modes

- Age outside 40–80 range — returns error; Enright equations are not validated outside derivation range
- Missing required sex or age parameters — returns 400 validation error
- Height or weight outside plausible bounds (e.g. height_cm < 50 or > 250) — returns validation error
- Providing neither height_cm nor height_in — returns error requiring at least one height input
- walked_m outside 0–1500 range — returns validation error
- Conflicting or implausible anthropometric combinations may produce extreme but technically valid outputs

## How this service works

Enright 1998 predicted six-minute walk distance (meters) from sex, age 40-80, height_cm, and weight_kg (Table 3 height/weight: male 7.57H−5.02age−1.76W−309; female 2.11H−2.29W−5.78age+667). Reports predicted_m and lln_m (minus 153 m men or 139 m women). Optional walked_m (0-1500) yields percent_predicted. Not a timed walk, BMI-equation path, or 80%/400 m class. Not a medical device.

## Output

Returns predicted_m (the Enright 1998 predicted six-minute walk distance in meters for the given sex, age, height, and weight), lln_m (lower limit of normal: predicted minus 153 m for males or 139 m for females), and optionally percent_predicted (walked_m divided by predicted_m times 100) when walked_m is supplied.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "required": [
      "sex",
      "age"
     ],
     "properties": {
      "age": {
       "type": "integer",
       "description": "Age in years (integer 40-80). Enright 1998 derivation range."
      },
      "sex": {
       "enum": [
        "female",
        "male"
       ],
       "type": "string",
       "description": "Sex used by Enright 1998 Table 3 (separate male and female height/weight equations)."
      },
      "walked_m": {
       "type": "number",
       "description": "Optional distance walked in meters (0-1500). When present, percent_predicted = walked_m / predicted_m × 100. magent does not time the walk."
      },
      "height_cm": {
       "type": "number",
       "description": "Height in centimeters (50-250). Provide height_cm or height_in."
      },
      "height_in": {
       "type": "number",
       "description": "Height in inches (20-98). Converted as cm = in × 2.54."
      },
      "weight_kg": {
       "type": "number",
       "description": "Weight in kilograms (1-500). Provide weight_kg or weight_lb."
      },
      "weight_lb": {
       "type": "number",
       "description": "Weight in pounds (2-1100). Converted as kg = lb × 0.45359237."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/enright-1998-six-minute-walk-distance-calculator-34a3d188/health.json
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