The fat-burning heart rate zone is a range of your maximum heart rate that optimizes fat metabolism during cardiovascular exercise. When you exercise within this zone, your body tends to utilize a higher percentage of calories from fat stores for energy compared to higher intensity zones, which rely more on carbohydrates.
A commonly used method to estimate your maximum heart rate is the Tanaka formula: 208 – (0.7 * age). However, individual maximum heart rates can vary. If you know your estimated maximum heart rate from a stress test or other reliable method, you can input that directly for a more personalized calculation.
The generally accepted fat burn heart rate zone is between 60% and 70% of your maximum heart rate. This zone offers a good balance between calorie expenditure and exercise intensity, making it sustainable for longer durations and effective for fat loss.
How to Use This Calculator:
Your Age: Enter your current age.
Estimated Maximum Heart Rate (bpm): If you know your estimated maximum heart rate, enter it here. If not, you can leave it blank, and the calculator will estimate it using the formula 208 – (0.7 * age).
Click "Calculate Fat Burn Zone".
The calculator will then display your target heart rate range for optimal fat burning during exercise. Remember to consult with a healthcare professional before starting any new exercise program.
function calculateFatBurnZone() {
var age = parseFloat(document.getElementById("age").value);
var maxHeartRateInput = document.getElementById("maxHeartRate").value;
var resultDiv = document.getElementById("result");
var maxHeartRate;
if (isNaN(age) || age = 120) {
resultDiv.innerHTML = "Please enter a valid age.";
return;
}
if (maxHeartRateInput && !isNaN(parseFloat(maxHeartRateInput)) && parseFloat(maxHeartRateInput) > 0) {
maxHeartRate = parseFloat(maxHeartRateInput);
} else {
// Estimate Max Heart Rate using Tanaka formula: 208 – (0.7 * age)
maxHeartRate = 208 – (0.7 * age);
if (maxHeartRate <= 0) {
resultDiv.innerHTML = "Calculated maximum heart rate is invalid. Please check your age.";
return;
}
}
// Calculate Fat Burn Zone (60% to 70% of Max Heart Rate)
var lowerBound = maxHeartRate * 0.60;
var upperBound = maxHeartRate * 0.70;
// Ensure bounds are not negative (should not happen with valid inputs but as a safeguard)
lowerBound = Math.max(0, lowerBound);
upperBound = Math.max(0, upperBound);
resultDiv.innerHTML = `