Heart Rate Zone Calculator Using Resting Heart Rate

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Heart Rate Zone Calculator (Karvonen Method)

Your Personalized Training Zones

Based on your Max Heart Rate ( bpm) and Heart Rate Reserve ( bpm).

Zone Intensity BPM Range
function calculateHeartZones() { var age = parseFloat(document.getElementById('hrAge').value); var resting = parseFloat(document.getElementById('restingHR').value); if (isNaN(age) || isNaN(resting) || age <= 0 || resting <= 0) { alert('Please enter valid positive numbers for Age and Resting Heart Rate.'); return; } // Standard Max HR formula var maxHR = 220 – age; // Heart Rate Reserve (HRR) var hrr = maxHR – resting; function getBPM(percentage) { // Karvonen Formula: ((Max HR – Resting HR) * Intensity) + Resting HR return Math.round((hrr * percentage) + resting); } var zones = [ { name: "Zone 1: Very Light", range: "50% – 60%", low: 0.50, high: 0.60, color: "#e3f2fd", label: "Warm-up / Active Recovery" }, { name: "Zone 2: Light", range: "60% – 70%", low: 0.60, high: 0.70, color: "#e8f5e9", label: "Fat Burning / Endurance" }, { name: "Zone 3: Moderate", range: "70% – 80%", low: 0.70, high: 0.80, color: "#fff9c4", label: "Aerobic / Cardiovascular Fitness" }, { name: "Zone 4: Hard", range: "80% – 90%", low: 0.80, high: 0.90, color: "#ffe0b2", label: "Anaerobic / Speed Endurance" }, { name: "Zone 5: Maximum", range: "90% – 100%", low: 0.90, high: 1.00, color: "#ffcdd2", label: "Red Line / Peak Effort" } ]; var tableHTML = ""; for (var i = 0; i < zones.length; i++) { var lowBPM = getBPM(zones[i].low); var highBPM = getBPM(zones[i].high); tableHTML += "" + "" + zones[i].name + "" + zones[i].label + "" + "" + zones[i].range + "" + "" + lowBPM + " – " + highBPM + " BPM" + ""; } document.getElementById('maxHRVal').innerText = maxHR; document.getElementById('hrrVal').innerText = hrr; document.getElementById('zoneTableBody').innerHTML = tableHTML; document.getElementById('hrResultArea').style.display = 'block'; }

Understanding Heart Rate Zones with the Karvonen Method

The Karvonen Formula is widely considered a more accurate way to determine exercise intensity than basic age-based formulas. Unlike the standard method (Max HR = 220 – Age), the Karvonen method incorporates your Resting Heart Rate (RHR) to calculate your Heart Rate Reserve (HRR).

Why Use Resting Heart Rate?

Your resting heart rate is a significant indicator of your cardiovascular fitness. A person with a lower RHR typically has a higher Heart Rate Reserve, meaning their heart is more efficient. By using the Karvonen formula, your training zones are tailored to your actual fitness level rather than just a generic age average.

The 5 Training Zones Explained

  • Zone 1 (50-60% HRR): Ideal for recovery and initial warm-ups. It improves overall health and helps with weight management.
  • Zone 2 (60-70% HRR): Often called the "Fat Burning Zone." It builds basic endurance and burns a higher percentage of calories from fat.
  • Zone 3 (70-80% HRR): The "Aerobic Zone." This improves blood circulation and strengthens the heart and lungs.
  • Zone 4 (80-90% HRR): The "Anaerobic Zone." High intensity training that increases your lactate threshold and speed.
  • Zone 5 (90-100% HRR): Maximal effort. Used for short intervals (sprints) to develop peak power and athletic performance.

Example Calculation

If a 40-year-old athlete has a resting heart rate of 60 BPM:

  1. Max HR: 220 – 40 = 180 BPM
  2. Heart Rate Reserve (HRR): 180 – 60 = 120 BPM
  3. 70% Target Zone: (120 * 0.70) + 60 = 144 BPM

Disclaimer: This calculator is for informational purposes. Always consult a physician before starting a high-intensity exercise program, especially if you have pre-existing cardiovascular conditions.

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