How to Calculate Your Exercise Heart Rate

Target Exercise Heart Rate Calculator

Calculate your optimal heart rate zones using the Karvonen Formula

50% – Very Light (Warm up) 60% – Light (Fat Burn) 70% – Moderate (Aerobic/Cardio) 80% – Hard (Anaerobic) 90% – Maximum (Sprints)
Your Target Heart Rate
— BPM
Max Heart Rate — BPM
Heart Rate Reserve — BPM

How to Calculate Your Exercise Heart Rate

Understanding your exercise heart rate is essential for maximizing the efficiency of your workouts while ensuring you stay within a safe cardiovascular range. Whether you are training for a marathon or just looking to improve your general health, calculating your Target Heart Rate (THR) provides a data-driven roadmap for your fitness journey.

The Karvonen Formula Explained

While many people use the simple "220 minus age" formula, fitness professionals prefer the Karvonen Formula. This method is more accurate because it accounts for your Resting Heart Rate (RHR), which is a key indicator of your current fitness level.

Formula:
1. Max Heart Rate (MHR) = 220 – Age
2. Heart Rate Reserve (HRR) = MHR – Resting Heart Rate
3. Target Heart Rate = (HRR × Intensity%) + Resting Heart Rate

Defining Heart Rate Zones

Different intensities yield different physiological results:

  • 50% – 60% (Moderate Activity): Ideal for beginners or warm-ups. Enhances recovery and metabolic health.
  • 60% – 70% (Weight Management): Often called the "Fat Burn Zone." The body utilizes a higher percentage of calories from fat.
  • 70% – 80% (Aerobic Zone): Improves cardiovascular endurance and strengthens the heart and lungs.
  • 80% – 90% (Anaerobic Zone): Increases your lactate threshold and improves high-intensity performance.

Example Calculation

If you are a 40-year-old with a resting heart rate of 60 BPM and you want to exercise at 70% intensity:

  1. Max HR: 220 – 40 = 180 BPM
  2. HR Reserve: 180 – 60 = 120 BPM
  3. Target: (120 × 0.70) + 60 = 144 BPM

In this scenario, your goal during your workout would be to keep your pulse around 144 beats per minute.

function calculateHR() { var age = document.getElementById('ageInput').value; var rhr = document.getElementById('rhrInput').value; var intensity = document.getElementById('intensityInput').value; if (age === "" || rhr === "" || age <= 0 || rhr <= 0) { alert("Please enter a valid Age and Resting Heart Rate."); return; } var ageNum = parseFloat(age); var rhrNum = parseFloat(rhr); var intensityDecimal = parseFloat(intensity) / 100; // 1. Calculate Maximum Heart Rate (Fox Formula) var maxHR = 220 – ageNum; // 2. Calculate Heart Rate Reserve (HRR) var hrReserve = maxHR – rhrNum; // 3. Calculate Target Heart Rate (Karvonen) var targetHR = (hrReserve * intensityDecimal) + rhrNum; // Display the results document.getElementById('targetDisplay').innerHTML = Math.round(targetHR) + " BPM"; document.getElementById('maxDisplay').innerHTML = Math.round(maxHR) + " BPM"; document.getElementById('reserveDisplay').innerHTML = Math.round(hrReserve) + " BPM"; // Show the result container document.getElementById('hrResult').style.display = "block"; // Smooth scroll to result document.getElementById('hrResult').scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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