heart_rate_zones

Instructions

Implementation Reference

• index.js:89-108 (handler)

  Core handler function `heartRateZones` that calculates heart rate training zones using the Karvonen method. Computes max heart rate (207 - 0.7*age if not provided), heart rate reserve (HRR), and five zones (Recovery, Aerobic, Tempo, Threshold, VO2max) with BPM ranges.

  function heartRateZones(age, restingHR, maxHR) {
    const mhr = maxHR || Math.round(207 - 0.7 * age);
    const hrr = mhr - restingHR;
    const zones = [
      { zone: 1, name: 'Recovery', low: 0.50, high: 0.60 },
      { zone: 2, name: 'Aerobic', low: 0.60, high: 0.70 },
      { zone: 3, name: 'Tempo', low: 0.70, high: 0.80 },
      { zone: 4, name: 'Threshold', low: 0.80, high: 0.90 },
      { zone: 5, name: 'VO2max', low: 0.90, high: 1.00 },
    ];
    return {
      maxHR: mhr,
      restingHR,
      zones: zones.map(z => ({
        ...z,
        bpmLow: Math.round(restingHR + hrr * z.low),
        bpmHigh: Math.round(restingHR + hrr * z.high),
      })),
    };
  }

• index.js:303-321 (registration)

  Tool registration of 'heart_rate_zones' using server.tool(). Defines schema (age required, resting_hr and max_hr optional) and async handler that calls heartRateZones() and formats output text.

  // Tool: heart_rate_zones
  server.tool(
    'heart_rate_zones',
    'Calculate heart rate training zones using the Karvonen method',
    {
      age: z.number().min(10).max(99).describe('Your age in years'),
      resting_hr: z.number().min(30).max(120).optional().describe('Resting heart rate in bpm (default: 60)'),
      max_hr: z.number().min(100).max(220).optional().describe('Known max heart rate in bpm (auto-calculated if omitted)'),
    },
    async ({ age, resting_hr, max_hr }) => {
      const result = heartRateZones(age, resting_hr || 60, max_hr);
      let text = `Heart Rate Training Zones (Karvonen Method)\n\nAge: ${age} | Resting HR: ${result.restingHR} bpm | Max HR: ${result.maxHR} bpm\n\n`;
      result.zones.forEach(z => {
        text += `Zone ${z.zone} (${z.name}): ${z.bpmLow}-${z.bpmHigh} bpm\n`;
      });
      text += `\nFor more options: ${BASE_URL}/tools/heart-rate-zones/`;
      return { content: [{ type: 'text', text }] };
    }
  );

• index.js:307-311 (schema)

  Input schema for the heart_rate_zones tool: age (z.number, 10-99, required), resting_hr (z.number, 30-120, optional, default 60), max_hr (z.number, 100-220, optional, auto-calculated).

  {
    age: z.number().min(10).max(99).describe('Your age in years'),
    resting_hr: z.number().min(30).max(120).optional().describe('Resting heart rate in bpm (default: 60)'),
    max_hr: z.number().min(100).max(220).optional().describe('Known max heart rate in bpm (auto-calculated if omitted)'),
  },