Heart Rate Running Zone Calculator

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Heart Rate Running Zone Calculator

Karvonen (Heart Rate Reserve) – More Accurate Percentage of Max HR (Standard)

Your Custom Training Zones

Zone Intensity Target BPM
function calculateHRZones() { var age = parseFloat(document.getElementById('runnerAge').value); var rhr = parseFloat(document.getElementById('restingHR').value); var method = document.getElementById('hrMethod').value; var resultArea = document.getElementById('hrResultArea'); var tableBody = document.getElementById('zoneTableBody'); var maxHRDisplay = document.getElementById('maxHRDisplay'); if (isNaN(age) || age 110) { alert("Please enter a valid age."); return; } if (isNaN(rhr) || rhr 120) { alert("Please enter a realistic resting heart rate (30-120 BPM)."); return; } // Standard Max HR formula (Fox formula) var maxHR = 220 – age; var hrr = maxHR – rhr; var zones = [ { name: "Zone 1 (Recovery)", desc: "Very Light (50-60%)", min: 0.50, max: 0.60, color: "#e0f2f1" }, { name: "Zone 2 (Aerobic)", desc: "Light (60-70%)", min: 0.60, max: 0.70, color: "#e8f5e9" }, { name: "Zone 3 (Tempo)", desc: "Moderate (70-80%)", min: 0.70, max: 0.80, color: "#fffde7" }, { name: "Zone 4 (Threshold)", desc: "Hard (80-90%)", min: 0.80, max: 0.90, color: "#fff3e0" }, { name: "Zone 5 (Anaerobic)", desc: "Maximum (90-100%)", min: 0.90, max: 1.00, color: "#ffebee" } ]; var html = ""; for (var i = 0; i < zones.length; i++) { var z = zones[i]; var lowBPM, highBPM; if (method === "karvonen") { lowBPM = Math.round((hrr * z.min) + rhr); highBPM = Math.round((hrr * z.max) + rhr); } else { lowBPM = Math.round(maxHR * z.min); highBPM = Math.round(maxHR * z.max); } html += ""; html += "" + z.name + ""; html += "" + z.desc + ""; html += "" + lowBPM + " – " + highBPM + " BPM"; html += ""; } maxHRDisplay.innerHTML = "Estimated Max Heart Rate: " + maxHR + " BPM"; tableBody.innerHTML = html; resultArea.style.display = "block"; }

Understanding Running Heart Rate Zones

Training by heart rate is one of the most effective ways for runners to ensure they are working at the correct intensity for their specific goals. Whether you are training for your first 5K or looking to set a marathon personal best, using a Heart Rate Running Zone Calculator helps prevent overtraining and optimizes cardiovascular adaptations.

The Five Running Zones Explained

Heart rate training is typically divided into five zones based on a percentage of your maximum heart rate (MHR) or your heart rate reserve (HRR).

  • Zone 1 (50-60%): Recovery Zone. This is a very easy pace used for warm-ups, cool-downs, and recovery runs after hard efforts. It improves overall health and helps with muscle repair.
  • Zone 2 (60-70%): Aerobic Base. Often called the "fat-burning zone," this is where most of your base mileage should happen. It builds endurance and strengthens the heart.
  • Zone 3 (70-80%): Tempo Zone. This is a moderate intensity. It improves aerobic capacity and prepares the body for faster running. You should be able to speak in short sentences.
  • Zone 4 (80-90%): Lactate Threshold. This is "comfortably hard." Training here improves your speed endurance and helps your body process lactic acid more efficiently.
  • Zone 5 (90-100%): Maximum Effort. This zone is reserved for interval training and sprints. It develops peak power and anaerobic capacity but can only be sustained for very short periods.

Karvonen Method vs. Max HR Percentage

This calculator provides two options for determining your zones:

Percentage of Max HR: A simple method that calculates zones based solely on your age-predicted maximum heart rate (220 – Age). While easy to use, it doesn't account for your individual fitness level.

Karvonen Method (Heart Rate Reserve): This is widely considered more accurate for athletes. It incorporates your Resting Heart Rate (RHR). By using the "Heart Rate Reserve" (the difference between your Max HR and your resting pulse), the zones are tailored to your current cardiovascular fitness. A lower resting heart rate usually indicates higher fitness, and the Karvonen method adjusts your target zones accordingly.

Example Calculation

If you are a 40-year-old runner with a resting heart rate of 60 BPM:

  1. Max HR: 220 – 40 = 180 BPM.
  2. Heart Rate Reserve: 180 – 60 = 120 BPM.
  3. Zone 2 (Karvonen 60%): (120 * 0.60) + 60 = 132 BPM.

In this example, your aerobic base training (Zone 2) would begin at 132 BPM, providing a personalized target that reflects both your age and your fitness level.

Tips for Success

To get the most out of this calculator, try to measure your resting heart rate first thing in the morning while still in bed. For the most accurate "Max HR," consider performing a field test (like a hill repeat test), as the 220-age formula is a general estimate and can vary by +/- 10-12 beats per minute for individuals.

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