Heart Rate Zone Calculator (Lactate Threshold Method)
This calculator helps you determine your personalized heart rate training zones based on your lactate threshold (LT). Understanding these zones is crucial for optimizing your training, whether you're aiming for endurance, speed, or recovery. Your lactate threshold is the exercise intensity at which lactate begins to accumulate in your bloodstream faster than it can be cleared. Training around your LT is a highly effective way to improve your aerobic capacity and performance.
Calculate Zones
Your Heart Rate Training Zones:
function calculateHeartRateZones() {
var ltHR = parseFloat(document.getElementById("lactateThresholdHeartRate").value);
var resultsDiv = document.getElementById("results");
resultsDiv.style.display = "block";
if (isNaN(ltHR) || ltHR <= 0) {
document.getElementById("zone1").innerHTML = "Please enter a valid Lactate Threshold Heart Rate (bpm).";
document.getElementById("zone2").innerHTML = "";
document.getElementById("zone3").innerHTML = "";
document.getElementById("zone4").innerHTML = "";
document.getElementById("zone5").innerHTML = "";
return;
}
// Zone 1: Recovery (0-89% of LT HR)
var zone1Lower = 0;
var zone1Upper = Math.round(ltHR * 0.89);
document.getElementById("zone1").innerHTML = "
Zone 1 (Recovery): " + zone1Lower + " – " + zone1Upper + " bpm (Easy, active recovery)";
// Zone 2: Aerobic / Endurance (90-100% of LT HR)
var zone2Lower = Math.round(ltHR * 0.90);
var zone2Upper = ltHR; // LT HR itself is the upper limit of Zone 2
document.getElementById("zone2").innerHTML = "
Zone 2 (Aerobic/Endurance): " + zone2Lower + " – " + zone2Upper + " bpm (Builds endurance, improves fat burning)";
// Zone 3: Threshold / Tempo (101-105% of LT HR)
var zone3Lower = Math.round(ltHR * 1.01);
var zone3Upper = Math.round(ltHR * 1.05);
document.getElementById("zone3").innerHTML = "
Zone 3 (Threshold/Tempo): " + zone3Lower + " – " + zone3Upper + " bpm (Improves lactate threshold and speed)";
// Zone 4: VO2 Max (106-110% of LT HR)
var zone4Lower = Math.round(ltHR * 1.06);
var zone4Upper = Math.round(ltHR * 1.10);
document.getElementById("zone4").innerHTML = "
Zone 4 (VO2 Max): " + zone4Lower + " – " + zone4Upper + " bpm (Increases maximal oxygen uptake)";
// Zone 5: Max Effort (111%+ of LT HR)
var zone5Lower = Math.round(ltHR * 1.11);
document.getElementById("zone5").innerHTML = "
Zone 5 (Max Effort): " + zone5Lower + "+ bpm (Short bursts of maximal effort, very high intensity)";
}
.calculator-wrapper {
font-family: sans-serif;
padding: 20px;
border: 1px solid #ccc;
border-radius: 8px;
max-width: 600px;
margin: 20px auto;
background-color: #f9f9f9;
}
.calculator-wrapper h2 {
text-align: center;
color: #333;
margin-bottom: 15px;
}
.calculator-wrapper p {
color: #555;
line-height: 1.6;
margin-bottom: 20px;
text-align: justify;
}
.calculator-inputs {
margin-bottom: 20px;
}
.form-group {
margin-bottom: 15px;
display: flex;
flex-direction: column;
}
.form-group label {
margin-bottom: 5px;
font-weight: bold;
color: #444;
}
.form-group input[type="number"] {
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
}
.calculator-wrapper button {
display: block;
width: 100%;
padding: 12px;
background-color: #007bff;
color: white;
border: none;
border-radius: 4px;
font-size: 18px;
cursor: pointer;
transition: background-color 0.3s ease;
margin-bottom: 20px;
}
.calculator-wrapper button:hover {
background-color: #0056b3;
}
.calculator-results {
border-top: 1px solid #eee;
padding-top: 15px;
display: none; /* Hidden by default until calculated */
}
.calculator-results h3 {
color: #333;
margin-bottom: 10px;
}
.calculator-results div {
margin-bottom: 8px;
padding: 8px;
background-color: #fff;
border-radius: 4px;
border: 1px solid #e0e0e0;
color: #444;
}
.calculator-results strong {
color: #007bff;
}