Understanding your Threshold Heart Rate (THR) is crucial for effective cardiovascular training. The Threshold Heart Rate is the highest intensity level that you can sustain for an extended period (typically around an hour) without accumulating excessive fatigue. It's often associated with your lactate threshold, the point at which lactate begins to build up in your blood faster than it can be cleared. Training at or near your THR can significantly improve your endurance and aerobic capacity.
function calculateThresholdHeartRate() {
var age = document.getElementById("age").value;
var maxHeartRate = document.getElementById("maxHeartRate").value;
var intensityPercentage = document.getElementById("intensityPercentage").value;
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
var errors = [];
if (isNaN(age) || age 120) {
errors.push("Please enter a valid age between 1 and 120.");
}
if (isNaN(maxHeartRate) || maxHeartRate 250) {
errors.push("Please enter a valid estimated Maximum Heart Rate (bpm) between 1 and 250.");
}
if (isNaN(intensityPercentage) || intensityPercentage 100) {
errors.push("Please enter a valid Training Intensity percentage between 1 and 100.");
}
if (errors.length > 0) {
resultDiv.innerHTML = errors.join("");
return;
}
// Common formula for Threshold Heart Rate (often estimated using a percentage of Max HR)
// While more complex methods exist (e.g., Karvonen formula involving Resting HR),
// a direct percentage of Max HR is a common and simplified approach for THR.
// We will use a percentage of the provided Maximum Heart Rate.
var thresholdHeartRate = (maxHeartRate * (intensityPercentage / 100));
resultDiv.innerHTML = "