Heart Rate Zone Calculation

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Heart Rate Zone Calculator

Understanding your heart rate zones can significantly enhance your fitness training, helping you optimize workouts for different goals like endurance, fat burning, and anaerobic capacity. This calculator helps you determine your personal heart rate zones based on your age and your resting heart rate.

What are Heart Rate Zones?

Heart rate zones are ranges of your heart rate, expressed as a percentage of your maximum heart rate, that correspond to different levels of exercise intensity. Training within specific zones can help you achieve particular fitness goals:

  • Zone 1 (Very Light): 50-60% of Maximum Heart Rate. Aids recovery and is ideal for warm-ups and cool-downs.
  • Zone 2 (Light): 60-70% of Maximum Heart Rate. Builds aerobic base and endurance. You can comfortably hold a conversation.
  • Zone 3 (Moderate): 70-80% of Maximum Heart Rate. Improves aerobic fitness and endurance. Talking becomes more challenging.
  • Zone 4 (Hard): 80-90% of Maximum Heart Rate. Improves anaerobic threshold and speed. Talking in short sentences is possible.
  • Zone 5 (Maximum): 90-100% of Maximum Heart Rate. Improves speed and power. Very short bursts of intense effort.

This calculator uses the widely accepted Karvonen Formula, which accounts for your resting heart rate for a more personalized calculation. The formula for Heart Rate Reserve (HRR) is: HRR = Max Heart Rate – Resting Heart Rate. Then, for each zone, you calculate: Target Heart Rate = (HRR * %Intensity) + Resting Heart Rate.

Example Calculation:

Let's say you are 30 years old and your resting heart rate is 60 bpm.

  1. Maximum Heart Rate (MHR) is typically estimated as 220 – Age. So, 220 – 30 = 190 bpm.
  2. Heart Rate Reserve (HRR) is MHR – Resting Heart Rate. So, 190 – 60 = 130 bpm.
  3. Zone 1 (50-60%): (130 * 0.50) + 60 = 125 bpm to (130 * 0.60) + 60 = 138 bpm.
  4. Zone 2 (60-70%): (130 * 0.60) + 60 = 138 bpm to (130 * 0.70) + 60 = 151 bpm.
  5. Zone 3 (70-80%): (130 * 0.70) + 60 = 151 bpm to (130 * 0.80) + 60 = 164 bpm.
  6. Zone 4 (80-90%): (130 * 0.80) + 60 = 164 bpm to (130 * 0.90) + 60 = 177 bpm.
  7. Zone 5 (90-100%): (130 * 0.90) + 60 = 177 bpm to (130 * 1.00) + 60 = 190 bpm.
var calculateHeartRateZones = function() { var age = parseFloat(document.getElementById("age").value); var restingHeartRate = parseFloat(document.getElementById("restingHeartRate").value); var resultDiv = document.getElementById("result"); resultDiv.innerHTML = "; // Clear previous results if (isNaN(age) || isNaN(restingHeartRate) || age <= 0 || restingHeartRate <= 0) { resultDiv.innerHTML = 'Please enter valid positive numbers for age and resting heart rate.'; return; } var maxHeartRate = 220 – age; var heartRateReserve = maxHeartRate – restingHeartRate; if (heartRateReserve < 0) { resultDiv.innerHTML = 'Your resting heart rate seems unusually high for your age. Please check your inputs.'; return; } var zones = { zone1: { min: Math.round(heartRateReserve * 0.50 + restingHeartRate), max: Math.round(heartRateReserve * 0.60 + restingHeartRate) }, zone2: { min: Math.round(heartRateReserve * 0.60 + restingHeartRate), max: Math.round(heartRateReserve * 0.70 + restingHeartRate) }, zone3: { min: Math.round(heartRateReserve * 0.70 + restingHeartRate), max: Math.round(heartRateReserve * 0.80 + restingHeartRate) }, zone4: { min: Math.round(heartRateReserve * 0.80 + restingHeartRate), max: Math.round(heartRateReserve * 0.90 + restingHeartRate) }, zone5: { min: Math.round(heartRateReserve * 0.90 + restingHeartRate), max: Math.round(heartRateReserve * 1.00 + restingHeartRate) } }; var outputHTML = '

Your Heart Rate Zones:

'; outputHTML += 'Maximum Heart Rate (MHR): ' + maxHeartRate + ' bpm'; outputHTML += 'Heart Rate Reserve (HRR): ' + heartRateReserve + ' bpm'; outputHTML += '
'; outputHTML += 'Zone 1 (50-60%): ' + zones.zone1.min + ' – ' + zones.zone1.max + ' bpm (Very Light)'; outputHTML += 'Zone 2 (60-70%): ' + zones.zone2.min + ' – ' + zones.zone2.max + ' bpm (Light)'; outputHTML += 'Zone 3 (70-80%): ' + zones.zone3.min + ' – ' + zones.zone3.max + ' bpm (Moderate)'; outputHTML += 'Zone 4 (80-90%): ' + zones.zone4.min + ' – ' + zones.zone4.max + ' bpm (Hard)'; outputHTML += 'Zone 5 (90-100%): ' + zones.zone5.min + ' – ' + zones.zone5.max + ' bpm (Maximum)'; outputHTML += '
'; resultDiv.innerHTML = outputHTML; }; .calculator-container { font-family: sans-serif; display: flex; flex-wrap: wrap; gap: 20px; max-width: 900px; margin: 20px auto; padding: 20px; border: 1px solid #ddd; border-radius: 8px; background-color: #f9f9f9; } .calculator-form { flex: 1; min-width: 300px; padding: 15px; background-color: #fff; border-radius: 5px; box-shadow: 0 2px 4px rgba(0,0,0,0.1); } .calculator-form h2 { margin-top: 0; color: #333; border-bottom: 1px solid #eee; padding-bottom: 10px; margin-bottom: 20px; } .form-group { margin-bottom: 15px; } .form-group label { display: block; margin-bottom: 5px; font-weight: bold; color: #555; } .form-group input[type="number"] { width: calc(100% – 16px); padding: 8px; border: 1px solid #ccc; border-radius: 4px; font-size: 1rem; } .calculator-form button { background-color: #4CAF50; color: white; padding: 10px 15px; border: none; border-radius: 4px; cursor: pointer; font-size: 1rem; transition: background-color 0.3s ease; } .calculator-form button:hover { background-color: #45a049; } .calculator-result { margin-top: 20px; padding: 15px; border: 1px solid #e0e0e0; border-radius: 5px; background-color: #f0f0f0; } .calculator-result h3 { margin-top: 0; color: #333; margin-bottom: 10px; } .zone-list p { margin-bottom: 8px; color: #444; } .calculator-explanation { flex: 1.5; min-width: 300px; padding: 15px; background-color: #fff; border-radius: 5px; box-shadow: 0 2px 4px rgba(0,0,0,0.1); } .calculator-explanation h3 { color: #333; border-bottom: 1px solid #eee; padding-bottom: 10px; margin-bottom: 20px; } .calculator-explanation ul, .calculator-explanation ol { padding-left: 20px; color: #444; line-height: 1.6; } .calculator-explanation li { margin-bottom: 10px; } .calculator-explanation strong { color: #333; }

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