Mastering Your Training: The Target Heart Rate Chart
Understanding your target heart rate is the cornerstone of effective cardiovascular training. Whether you are an elite athlete aiming to improve your VO2 max or a beginner looking to burn fat safely, knowing your numbers ensures you are training at the right intensity. This Target Heart Rate Chart Calculator helps you customize your training zones based on your specific physiology.
Why Use a Personalized Heart Rate Chart?
Generic charts found in gym locker rooms are often too broad. By inputting your age and optionally your Resting Heart Rate (RHR), this calculator generates a specific profile for you. Training in specific "zones" yields different physiological adaptations:
Fat Burning (Zone 2): Operates at a lower intensity where the body primarily utilizes fat stores for fuel.
Aerobic Endurance (Zone 3): Improves cardiovascular health and lung capacity.
Anaerobic Performance (Zone 4): Increases lactate threshold, allowing you to sustain high-intensity efforts for longer.
The Formulas Behind the Calculation
This calculator employs two primary methods depending on the data you provide:
1. The Standard Method (Age-Predicted)
If you only provide your age, the calculator uses the standard formula: MHR = 220 - Age. The zones are then calculated as straight percentages of this Maximum Heart Rate (MHR). This is a great starting point for most general fitness enthusiasts.
2. The Karvonen Formula (Heart Rate Reserve)
If you input your Resting Heart Rate, the calculator upgrades to the Karvonen Formula. This is generally considered more accurate because it accounts for your baseline fitness level. The formula is:
Using the Karvonen method often results in slightly higher target numbers, preventing fit individuals from undertraining.
How to Determine Your Resting Heart Rate
To get the most accurate results from this calculator:
Check your pulse immediately after waking up in the morning, before getting out of bed.
Count the beats for 60 seconds (or 15 seconds multiplied by 4).
Repeat this for 3 days and take the average.
Safety Considerations
While the "220 minus age" rule is a standard in the fitness industry, individual Maximum Heart Rates can vary significantly (by as much as 10-20 beats per minute). Before beginning any vigorous exercise program, especially if you have a history of heart conditions, please consult with a healthcare professional. Use these zones as guidelines, but listen to your body first.
function calculateHeartRateZones() {
// 1. Get Input Values
var ageInput = document.getElementById('userAge');
var rhrInput = document.getElementById('restingHR');
var resultSection = document.getElementById('results');
var age = parseInt(ageInput.value);
var rhr = parseInt(rhrInput.value);
// 2. Validation
if (!age || age 120) {
alert("Please enter a valid age between 1 and 120.");
return;
}
// 3. Calculate Max Heart Rate (Standard Formula)
var mhr = 220 – age;
// Check if RHR is valid number
var useKarvonen = false;
if (!isNaN(rhr) && rhr > 30 && rhr < 150) {
useKarvonen = true;
}
// 4. Update UI Header
document.getElementById('displayMHR').innerText = mhr + " BPM";
document.getElementById('methodUsed').innerText = useKarvonen ?
"Calculation Method: Karvonen Formula (Heart Rate Reserve)" :
"Calculation Method: Standard Age-Based Formula";
// 5. Define Zones Data
// Zones: 1 (50-60%), 2 (60-70%), 3 (70-80%), 4 (80-90%), 5 (90-100%)
var zones = [
{ id: 5, name: "Zone 5: Maximum", minPct: 0.90, maxPct: 1.00, desc: "Max Performance / Speed", css: "zone-row-5" },
{ id: 4, name: "Zone 4: Hard", minPct: 0.80, maxPct: 0.90, desc: "Anaerobic Capacity", css: "zone-row-4" },
{ id: 3, name: "Zone 3: Moderate", minPct: 0.70, maxPct: 0.80, desc: "Aerobic Fitness", css: "zone-row-3" },
{ id: 2, name: "Zone 2: Light", minPct: 0.60, maxPct: 0.70, desc: "Fat Burning / Endurance", css: "zone-row-2" },
{ id: 1, name: "Zone 1: Very Light", minPct: 0.50, maxPct: 0.60, desc: "Warm Up / Recovery", css: "zone-row-1" }
];
var tableHtml = "";
// 6. Calculation Logic Loop
for (var i = 0; i < zones.length; i++) {
var zone = zones[i];
var minBpm, maxBpm;
if (useKarvonen) {
// Karvonen: Target = ((MHR – RHR) * %) + RHR
var hrr = mhr – rhr;
minBpm = Math.round((hrr * zone.minPct) + rhr);
maxBpm = Math.round((hrr * zone.maxPct) + rhr);
} else {
// Standard: Target = MHR * %
minBpm = Math.round(mhr * zone.minPct);
maxBpm = Math.round(mhr * zone.maxPct);
}
// Generate Table Row
tableHtml += "