When you exercise, your body uses different types of fuel. The intensity of your workout determines which fuel source is prioritized. Exercising within your "fat-burning zone" means your heart rate is at a level where your body primarily burns fat for energy. This doesn't necessarily mean you're burning the most calories overall, but it targets fat as the primary fuel source.
The fat-burning heart rate zone is typically estimated to be between 60% and 70% of your maximum heart rate. Your maximum heart rate is often estimated by subtracting your age from 220. This is a general guideline, and individual responses can vary.
To calculate your fat-burning heart rate zone, you'll need to know your age. The calculator below will estimate your maximum heart rate and then determine the range for your fat-burning zone.
Fat Burning Heart Rate Calculator
function calculateFatBurningHeartRate() {
var ageInput = document.getElementById("age");
var resultDiv = document.getElementById("result");
var age = parseFloat(ageInput.value);
if (isNaN(age) || age < 0) {
resultDiv.innerHTML = "Please enter a valid age.";
return;
}
// Estimate Maximum Heart Rate (MHR) using the common formula: 220 – age
var maxHeartRate = 220 – age;
// Calculate the fat-burning zone (60% to 70% of MHR)
var lowerFatBurnRate = Math.round(maxHeartRate * 0.60);
var upperFatBurnRate = Math.round(maxHeartRate * 0.70);
resultDiv.innerHTML = "Your estimated Maximum Heart Rate is: " + maxHeartRate + " bpm" +
"Your Fat Burning Heart Rate Zone is: " + lowerFatBurnRate + " bpm to " + upperFatBurnRate + " bpm";
}