Heart Rate Zone Calculator Karvonen

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Karvonen Heart Rate Zone Calculator

Please enter valid positive numbers for Age and Resting HR.

Your Personalized Training Zones

Max Heart Rate (Estimated): BPM

Heart Rate Reserve (HRR): BPM

Zone Intensity Target Heart Rate Range
Zone 1 50% – 60% (Recovery) BPM
Zone 2 60% – 70% (Aerobic / Fat Burn) BPM
Zone 3 70% – 80% (Endurance) BPM
Zone 4 80% – 90% (Anaerobic / Threshold) BPM
Zone 5 90% – 100% (VO2 Max / Redline) BPM

What is the Karvonen Formula?

The Karvonen formula is a mathematical method used to determine your target heart rate training zones. Unlike the simple "220 minus age" formula, the Karvonen method incorporates your Resting Heart Rate (RHR). This makes it significantly more accurate because it accounts for your individual fitness level.

By including your Heart Rate Reserve (the difference between your maximum and resting heart rate), the Karvonen calculation provides zones that are tailored to how hard your heart is actually working relative to its capacity.

How to Calculate Karvonen Training Zones

To calculate your target heart rate (THR) using this method, follow these steps:

  1. Find Max HR: 220 – Age = Max HR.
  2. Find Heart Rate Reserve (HRR): Max HR – Resting HR = HRR.
  3. Calculate Target Range: (HRR × Intensity%) + Resting HR = Target HR.

Real-World Example

Let's look at a 40-year-old individual with a resting heart rate of 60 BPM who wants to train in Zone 3 (70% intensity):

  • Max HR: 220 – 40 = 180 BPM
  • HRR: 180 – 60 = 120 BPM
  • Target (70%): (120 × 0.70) + 60 = 84 + 60 = 144 BPM

Understanding the Heart Rate Zones

Zone 1 (50-60%): Best for warm-ups, cool-downs, and active recovery. It improves overall health and helps with injury prevention.

Zone 2 (60-70%): Often called the "Fat Burning Zone." This builds basic endurance and efficiency, allowing you to train for longer durations.

Zone 3 (70-80%): The "Aerobic Zone." This improves cardiovascular capacity and respiratory efficiency. It is the core zone for most endurance runners and cyclists.

Zone 4 (80-90%): The "Anaerobic Zone." This increases your lactate threshold. You will feel breathless and your muscles will feel heavy.

Zone 5 (90-100%): The "Redline Zone." This is used for high-intensity interval training (HIIT) and improves maximal performance and speed.

Tips for Accurate Measurement

To get the most out of this calculator, ensure you measure your Resting Heart Rate correctly. The best time to measure it is first thing in the morning, immediately after waking up, while you are still lying in bed. Use a pulse monitor or manually count your beats for 60 seconds for the highest accuracy.

function calculateKarvonen() { var age = document.getElementById('userAge').value; var restHR = document.getElementById('restHR').value; var errorDiv = document.getElementById('error-message'); var resultsDiv = document.getElementById('results'); // Validation if (age === "" || restHR === "" || age <= 0 || restHR <= 0) { errorDiv.style.display = 'block'; resultsDiv.style.display = 'none'; return; } errorDiv.style.display = 'none'; var nAge = parseFloat(age); var nRest = parseFloat(restHR); // Core Formula Logic var maxHR = 220 – nAge; var hrr = maxHR – nRest; // Display basic stats document.getElementById('maxHRVal').innerText = maxHR; document.getElementById('hrrVal').innerText = hrr; // Calculate Zones Helper function getTHR(intensity) { return Math.round((hrr * intensity) + nRest); } // Zone 1: 50-60% document.getElementById('z1-range').innerText = getTHR(0.50) + " – " + getTHR(0.60); // Zone 2: 60-70% document.getElementById('z2-range').innerText = getTHR(0.60) + " – " + getTHR(0.70); // Zone 3: 70-80% document.getElementById('z3-range').innerText = getTHR(0.70) + " – " + getTHR(0.80); // Zone 4: 80-90% document.getElementById('z4-range').innerText = getTHR(0.80) + " – " + getTHR(0.90); // Zone 5: 90-100% document.getElementById('z5-range').innerText = getTHR(0.90) + " – " + maxHR; resultsDiv.style.display = 'block'; }

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