{
  "tool_id": "zone_2_heart_rate",
  "slug": "zone-2-heart-rate-calculator",
  "path": "/zone-2-heart-rate-calculator/",
  "mode": "engine_module",
  "usage": "Client-side calculator. Open https://aifithub.io/zone-2-heart-rate-calculator/ and fill in the inputs; results render in-browser. Also importable as ES module from https://aifithub.io/engines/zone-2-heart-rate-calculator.js — call compute(input) with the JSON shape below.",
  "methodology": "https://aifithub.io/methodology/zone-2-heart-rate-calculator/",
  "sample_input": {
    "tool": "zone_2_heart_rate",
    "age": 35,
    "resting_hr": 62,
    "methods": [
      "maffetone",
      "percentage",
      "karvonen",
      "lactate"
    ]
  },
  "input_schema": {
    "type": "object",
    "properties": {
      "tool": {
        "type": "string"
      },
      "age": {
        "type": "number"
      },
      "resting_hr": {
        "type": "number"
      },
      "max_hr": {
        "type": "number"
      },
      "methods": {
        "type": "array",
        "items": {
          "type": "string",
          "enum": [
            "maffetone",
            "percentage",
            "karvonen",
            "lactate"
          ]
        }
      }
    },
    "required": [
      "tool",
      "age"
    ]
  },
  "output_schema": {
    "type": "object",
    "properties": {
      "methods": {
        "type": "array"
      },
      "estimatedMaxHrTraditional": {
        "type": "number"
      },
      "estimatedMaxHrTanaka": {
        "type": "number"
      },
      "hasRhr": {
        "type": "boolean"
      },
      "hasCustomMaxHr": {
        "type": "boolean"
      }
    }
  }
}