Zone 2 heart rate training is a crucial component of endurance development. It's the intensity level where your body primarily burns fat for fuel and improves mitochondrial function, leading to enhanced aerobic capacity and overall athletic performance.
The most common and widely accepted method to calculate your Zone 2 heart rate is using a percentage of your Maximum Heart Rate (MHR). There are several formulas to estimate MHR, but a simple and frequently used one is the Tanaka formula: 208 – (0.7 x Age). Once you have your estimated MHR, Zone 2 is typically considered to be between 60% and 70% of your MHR.
#zone2-calculator {
font-family: sans-serif;
border: 1px solid #ccc;
padding: 20px;
border-radius: 8px;
max-width: 500px;
margin: 20px auto;
background-color: #f9f9f9;
}
.form-group {
margin-bottom: 15px;
}
.form-group label {
display: block;
margin-bottom: 5px;
font-weight: bold;
}
.form-group input[type="number"] {
width: calc(100% – 22px);
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
box-sizing: border-box;
}
button {
background-color: #4CAF50;
color: white;
padding: 10px 15px;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 16px;
margin-top: 10px;
}
button:hover {
background-color: #45a049;
}
#result {
margin-top: 20px;
padding: 15px;
border: 1px solid #eee;
border-radius: 4px;
background-color: #fff;
}
#result p {
margin: 0 0 10px 0;
}
#result strong {
color: #333;
}
function calculateZone2() {
var ageInput = document.getElementById("age");
var maxHeartRateInput = document.getElementById("maxHeartRate");
var resultDiv = document.getElementById("result");
var age = parseFloat(ageInput.value);
var maxHeartRate = parseFloat(maxHeartRateInput.value);
var estimatedMaxHeartRate;
if (isNaN(maxHeartRate) || maxHeartRate <= 0) {
if (isNaN(age) || age <= 0) {
resultDiv.innerHTML = "Please enter a valid age or estimated maximum heart rate.";
return;
}
// Tanaka formula: 208 – (0.7 x Age)
estimatedMaxHeartRate = 208 – (0.7 * age);
} else {
estimatedMaxHeartRate = maxHeartRate;
}
if (estimatedMaxHeartRate <= 0) {
resultDiv.innerHTML = "Estimated Maximum Heart Rate must be a positive number.";
return;
}
// Zone 2 is typically 60% to 70% of MHR
var lowerZone2 = estimatedMaxHeartRate * 0.60;
var upperZone2 = estimatedMaxHeartRate * 0.70;
resultDiv.innerHTML = "Your estimated Maximum Heart Rate is: " + estimatedMaxHeartRate.toFixed(0) + " BPM" +
"Your Zone 2 Heart Rate Range is:" +
"" + lowerZone2.toFixed(0) + " BPM to " + upperZone2.toFixed(0) + " BPM";
}