Measure your pulse for 60 seconds while fully relaxed.
Karvonen Formula (Recommended – Uses RHR)
Standard (220 – Age)
How to Calculate Your Actual Heart Rate Targets
Understanding your heart rate is crucial for effective training and cardiovascular health. While measuring your current pulse gives you a snapshot of the moment, calculating your Maximum Heart Rate (MHR) and Target Heart Rate Zones allows you to structure your exercise intensity accurately.
Why "Actual" Heart Rate Matters: Randomly exercising without a target can lead to two extremes: undertraining, where you see no results, or overtraining, which increases injury risk. Knowing your specific numbers tailors your workout to your biology.
The Formulas Used
There are two primary methods used to calculate heart rate limits:
Standard Method (MHR): This uses the classic formula 220 - Age. It provides a rough estimate of your maximum capacity but does not account for individual fitness levels.
Karvonen Method (HRR): This is considered more accurate for individuals with varying fitness levels. It uses your Heart Rate Reserve (HRR), which is the difference between your Maximum Heart Rate and your Resting Heart Rate.
Understanding the Calculation Steps
To calculate your target zones manually using the Karvonen method, follow these steps:
Find MHR: Calculate 220 minus your age.
Find RHR: Measure your pulse when you first wake up (Resting Heart Rate).
Calculate HRR: Subtract RHR from MHR.
Apply Intensity: Multiply HRR by your desired percentage (e.g., 0.70 for 70%).
Add RHR Back: Add your Resting Heart Rate to the result of step 4.
Heart Rate Training Zones
Different intensities trigger different metabolic responses in the body:
Zone 1 (50-60%): Very light activity, warm-up, and recovery. Aids in recovery and preparing muscles.
Zone 2 (60-70%): Fat burning zone. Ideal for building endurance and burning fat calories. Comfortable conversation is possible.
Zone 3 (70-80%): Aerobic zone. Improves cardiovascular system and respiratory rate. Sweating increases.
Zone 4 (80-90%): Anaerobic zone. High intensity for shorter durations. Improves VO2 max and lactate tolerance.
Zone 5 (90-100%): Maximum effort. Sustainable only for very short bursts (sprinting).
How to Measure Your Pulse Manually
If you do not have a wearable device, you can measure your actual heart rate by placing two fingers (index and middle) on your radial artery (wrist) or carotid artery (neck). Count the beats for 15 seconds and multiply by 4 to get your Beats Per Minute (BPM).
function calculateZones() {
// Get inputs
var ageInput = document.getElementById("hrAge");
var restingInput = document.getElementById("hrResting");
var formulaInput = document.getElementById("hrFormula");
var resultDiv = document.getElementById("hr-result");
var age = parseFloat(ageInput.value);
var restingHR = parseFloat(restingInput.value);
var formula = formulaInput.value;
// Validation
if (isNaN(age) || age 120) {
resultDiv.style.display = "block";
resultDiv.innerHTML = "Please enter a valid age between 1 and 120.";
return;
}
if (formula === "karvonen" && (isNaN(restingHR) || restingHR 150)) {
resultDiv.style.display = "block";
resultDiv.innerHTML = "Please enter a valid Resting Heart Rate (typically 30-150 BPM) for the Karvonen method.";
return;
}
// Calculate MHR (Standard 220-Age)
var maxHeartRate = 220 – age;
// Prepare variables for calculation
var heartRateReserve = 0;
if (formula === "karvonen") {
heartRateReserve = maxHeartRate – restingHR;
}
// Define Zones percentages
var zones = [
{ name: "Zone 1 (Warm Up)", min: 0.50, max: 0.60, desc: "Recovery / Very Light" },
{ name: "Zone 2 (Fat Burn)", min: 0.60, max: 0.70, desc: "Endurance / Light" },
{ name: "Zone 3 (Aerobic)", min: 0.70, max: 0.80, desc: "Cardio / Moderate" },
{ name: "Zone 4 (Anaerobic)", min: 0.80, max: 0.90, desc: "Hardcore / Heavy" },
{ name: "Zone 5 (Maximum)", min: 0.90, max: 1.00, desc: "Peak Effort" }
];
var tableRows = "";
for (var i = 0; i < zones.length; i++) {
var z = zones[i];
var minBPM, maxBPM;
if (formula === "karvonen") {
// Karvonen: (HRR * %) + RHR
minBPM = Math.round((heartRateReserve * z.min) + restingHR);
maxBPM = Math.round((heartRateReserve * z.max) + restingHR);
} else {
// Standard: MHR * %
minBPM = Math.round(maxHeartRate * z.min);
maxBPM = Math.round(maxHeartRate * z.max);
}
tableRows += "
" +
"
" + z.name + "" + z.desc + "
" +
"
" + (z.min * 100) + "% – " + (z.max * 100) + "%
" +
"
" + minBPM + " – " + maxBPM + " bpm
" +
"
";
}
// Output Construction
var outputHTML = "
";
outputHTML += "Max Heart Rate: " + maxHeartRate + " BPM";
if (formula === "karvonen") {
outputHTML += "Based on Karvonen Formula (RHR: " + restingHR + ")";
} else {
outputHTML += "Based on Standard Formula (220 – Age)";
}
outputHTML += "