Formula for Heart Rate Calculation

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Heart Rate Zone Calculator .hr-calculator-wrapper { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; max-width: 800px; margin: 20px auto; padding: 30px; background-color: #f8f9fa; border-radius: 12px; box-shadow: 0 4px 12px rgba(0,0,0,0.08); border: 1px solid #e9ecef; } .hr-calculator-wrapper h2 { text-align: center; color: #2c3e50; margin-bottom: 25px; font-size: 24px; } .hr-input-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-bottom: 25px; } .hr-input-group { display: flex; flex-direction: column; } .hr-input-group label { font-weight: 600; margin-bottom: 8px; color: #495057; font-size: 14px; } .hr-input-group input { padding: 12px; border: 2px solid #ced4da; border-radius: 8px; font-size: 16px; transition: border-color 0.2s; } .hr-input-group input:focus { border-color: #e74c3c; outline: none; } .hr-calc-btn { width: 100%; padding: 15px; background-color: #e74c3c; color: white; border: none; border-radius: 8px; font-size: 16px; font-weight: 700; cursor: pointer; transition: background-color 0.2s; text-transform: uppercase; letter-spacing: 0.5px; } .hr-calc-btn:hover { background-color: #c0392b; } .hr-result-container { margin-top: 30px; padding: 20px; background-color: #ffffff; border-radius: 8px; border: 1px solid #dee2e6; display: none; } .hr-result-header { text-align: center; margin-bottom: 20px; border-bottom: 2px solid #f1f3f5; padding-bottom: 15px; } .hr-metric { font-size: 32px; font-weight: 800; color: #e74c3c; display: block; } .hr-metric-label { font-size: 14px; color: #868e96; text-transform: uppercase; letter-spacing: 1px; } .hr-zone-table { width: 100%; border-collapse: collapse; margin-top: 15px; } .hr-zone-table th, .hr-zone-table td { padding: 12px; text-align: left; border-bottom: 1px solid #eee; } .hr-zone-table th { background-color: #f1f3f5; font-weight: 600; color: #495057; } .hr-zone-row-1 { border-left: 5px solid #bdc3c7; } /* Grey */ .hr-zone-row-2 { border-left: 5px solid #3498db; } /* Blue */ .hr-zone-row-3 { border-left: 5px solid #2ecc71; } /* Green */ .hr-zone-row-4 { border-left: 5px solid #f1c40f; } /* Yellow */ .hr-zone-row-5 { border-left: 5px solid #e74c3c; } /* Red */ .hr-content-section { max-width: 800px; margin: 40px auto; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; line-height: 1.6; color: #333; } .hr-content-section h3 { color: #2c3e50; border-bottom: 2px solid #e74c3c; padding-bottom: 10px; margin-top: 30px; } .hr-content-section p { margin-bottom: 15px; } .hr-formula-box { background-color: #f8f9fa; padding: 15px; border-left: 4px solid #e74c3c; font-family: monospace; margin: 15px 0; } @media (max-width: 600px) { .hr-input-grid { grid-template-columns: 1fr; } } function calculateHeartRateZones() { // Get Inputs var ageInput = document.getElementById('hr_age'); var rhrInput = document.getElementById('hr_resting_rate'); var resultContainer = document.getElementById('hr_results_display'); var age = parseFloat(ageInput.value); var rhr = parseFloat(rhrInput.value); // Validation if (isNaN(age) || age 120) { alert("Please enter a valid age between 1 and 120."); return; } // Calculate Max Heart Rate (Standard Fox Formula) var maxHR = 220 – age; // Check calculation method (Karvonen vs Standard) var useKarvonen = !isNaN(rhr) && rhr > 0 && rhr < maxHR; var methodText = useKarvonen ? "Karvonen Method (More Accurate)" : "Standard Age-Based Method"; // Generate Zones var zones = []; var percentages = [ { min: 0.50, max: 0.60, name: "Zone 1: Very Light", desc: "Warm up / Recovery" }, { min: 0.60, max: 0.70, name: "Zone 2: Light", desc: "Fat Burning / Endurance" }, { min: 0.70, max: 0.80, name: "Zone 3: Moderate", desc: "Aerobic Fitness" }, { min: 0.80, max: 0.90, name: "Zone 4: Hard", desc: "Anaerobic Performance" }, { min: 0.90, max: 1.00, name: "Zone 5: Maximum", desc: "Peak Effort / Speed" } ]; for (var i = 0; i < percentages.length; i++) { var z = percentages[i]; var lower, upper; if (useKarvonen) { // Target HR = ((Max HR − Resting HR) × %Intensity) + Resting HR var hrr = maxHR – rhr; // Heart Rate Reserve lower = Math.round((hrr * z.min) + rhr); upper = Math.round((hrr * z.max) + rhr); } else { // Target HR = Max HR × %Intensity lower = Math.round(maxHR * z.min); upper = Math.round(maxHR * z.max); } zones.push({ name: z.name, desc: z.desc, range: lower + " – " + upper + " bpm", cssClass: "hr-zone-row-" + (i + 1) }); } // Build Result HTML var html = '
'; html += '' + maxHR + ' bpm'; html += 'Estimated Maximum Heart Rate (MHR)'; html += '
Calculation Method: ' + methodText + '
'; html += '
'; html += ''; html += ''; html += ''; for (var j = 0; j < zones.length; j++) { html += ''; html += ''; html += ''; html += ''; html += ''; } html += '
ZoneIntensity DescriptionTarget Range
' + zones[j].name + '' + zones[j].desc + '' + zones[j].range + '
'; // Display Results resultContainer.innerHTML = html; resultContainer.style.display = "block"; }

Target Heart Rate Calculator

Enter for Karvonen Formula accuracy

Understanding the Formula for Heart Rate Calculation

Calculating your target heart rate is essential for maximizing the efficiency of your workouts, whether your goal is fat loss, cardiovascular endurance, or peak athletic performance. While wearable technology is popular, understanding the underlying mathematics allows you to tailor your training specifically to your physiology.

1. Maximum Heart Rate (MHR)

The first step in any heart rate calculation is determining your Maximum Heart Rate (MHR). This is the upper limit of what your cardiovascular system can handle during physical exertion. The most common formula used globally is the Fox Formula.

MHR = 220 − Age

For example, a 40-year-old individual would have an estimated MHR of 180 beats per minute (bpm). While this provides a solid baseline, it is a general estimate.

2. The Karvonen Formula (Advanced)

For a more personalized calculation, experts recommend the Karvonen Formula. Unlike the standard method which treats everyone of the same age equally, the Karvonen method incorporates your Resting Heart Rate (RHR). This accounts for your current fitness level, as fitter individuals typically have a lower RHR.

This method calculates the Heart Rate Reserve (HRR) first:

Heart Rate Reserve (HRR) = MHR − Resting Heart Rate

Once the reserve is known, the target heart rate for a specific intensity is calculated as:

Target HR = (HRR × Intensity %) + Resting Heart Rate

3. Heart Rate Training Zones

Effective training requires working within specific "zones" derived from the formulas above:

  • Zone 1 (50-60%): Very light intensity. Used for warm-ups and active recovery.
  • Zone 2 (60-70%): The "Fat Burning" zone. The body primarily uses fat as fuel. Ideal for long-duration endurance training.
  • Zone 3 (70-80%): Aerobic zone. Improves blood circulation and skeletal muscle strength.
  • Zone 4 (80-90%): Anaerobic threshold. Increases performance capacity and lactate tolerance.
  • Zone 5 (90-100%): Maximum effort. Sustainable only for very short bursts (sprinting).

Using the calculator above, you can determine exactly which heart rate numbers correspond to these zones based on your age and resting heart rate data.

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