Your Target Heart Rate Zone:
How the Karvonen Formula Works:
The formula involves a few steps:
- Estimate Maximum Heart Rate (MHR): A common estimation is 220 minus your age. So, MHR = 220 – Age.
- Calculate Heart Rate Reserve (HRR): This is the difference between your MHR and your resting heart rate. HRR = MHR – Resting Heart Rate.
- Calculate Target Heart Rate (THR): This is where you incorporate your desired exercise intensity. THR = (HRR × Intensity %) + Resting Heart Rate.
The calculator provides a target heart rate for the specified intensity percentage. For example, a 60% intensity would be for moderate aerobic exercise, while 80-85% would be for high-intensity interval training.
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function calculateKarvonen() {
var age = parseFloat(document.getElementById("age").value);
var restingHeartRate = parseFloat(document.getElementById("restingHeartRate").value);
var intensity = parseFloat(document.getElementById("intensity").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(age) || isNaN(restingHeartRate) || isNaN(intensity)) {
resultDiv.innerHTML = "
Please enter valid numbers for all fields.";
return;
}
if (age 120) {
resultDiv.innerHTML = "
Please enter a valid age.";
return;
}
if (restingHeartRate = 220) {
resultDiv.innerHTML = "
Please enter a valid resting heart rate (typically between 40-100 bpm).";
return;
}
if (intensity 90) {
resultDiv.innerHTML = "
Please enter an intensity percentage between 50% and 90%.";
return;
}
// 1. Estimate Maximum Heart Rate (MHR)
var maxHeartRate = 220 – age;
// 2. Calculate Heart Rate Reserve (HRR)
var heartRateReserve = maxHeartRate – restingHeartRate;
// 3. Calculate Target Heart Rate (THR) for the given intensity
var targetHeartRate = (heartRateReserve * (intensity / 100)) + restingHeartRate;
resultDiv.innerHTML =
"
" + targetHeartRate.toFixed(0) + " bpm" +
"(" + intensity.toFixed(0) + "% intensity)";
}