How to Calculate Training Zones Using Resting Heart Rate
Calculating your maximum heart rate and utilizing your resting heart rate is the most effective way to determine personalized training intensities. While many people rely solely on the simple "220 minus age" formula, incorporating your resting heart rate via the Karvonen Formula provides a much more accurate picture of your fitness level and training capacity.
Why Resting Heart Rate Matters
Your Resting Heart Rate (RHR) is a strong indicator of your cardiovascular health. A lower RHR typically indicates a stronger heart that can pump blood more efficiently. By factoring RHR into your calculations, you determine your Heart Rate Reserve (HRR).
The HRR represents the cushion of heartbeats available for exercise. Two people of the same age may have the same Maximum Heart Rate, but if one has a resting rate of 50 bpm and the other 80 bpm, their training zones should be significantly different. The calculator above accounts for this difference.
The Tanaka vs. Standard Formula
This calculator primarily utilizes the Tanaka Formula (208 – 0.7 × Age) to estimate Maximum Heart Rate. Medical research suggests this is often more accurate for healthy adults than the traditional (220 – Age) method, which tends to overestimate max heart rate in younger people and underestimate it in older adults.
Understanding the Training Zones
Zone 1 (Very Light): Used for warm-ups and recovery. It helps with blood flow and minimizes fatigue.
Zone 2 (Light): The "fat burning" zone. Great for building basic endurance and can be sustained for long periods.
Zone 3 (Moderate): Improves aerobic fitness and blood circulation in skeletal muscles.
Zone 4 (Hard): Increases maximum performance capacity. This is the anaerobic threshold zone.
Zone 5 (Maximum): For short bursts of high-intensity interval training. Develops speed and neuromuscular coordination.
How to Measure Resting Heart Rate
To get the most accurate result from the calculator above, measure your pulse immediately after waking up in the morning, before getting out of bed. Count the beats for 60 seconds. Do this for 3-4 days and take the average for your input.
function calculateHeartRate() {
// 1. Get Inputs
var ageInput = document.getElementById('input_age').value;
var rhrInput = document.getElementById('input_rhr').value;
// 2. Validate Inputs
if (ageInput === "" || rhrInput === "") {
alert("Please enter both your Age and Resting Heart Rate.");
return;
}
var age = parseFloat(ageInput);
var rhr = parseFloat(rhrInput);
if (isNaN(age) || age 120) {
alert("Please enter a valid age.");
return;
}
if (isNaN(rhr) || rhr 200) {
alert("Please enter a valid resting heart rate.");
return;
}
// 3. Logic Calculations
// Calculate Max Heart Rate (Tanaka Formula: 208 – (0.7 * age))
var maxHR = 208 – (0.7 * age);
// Alternative standard formula (220 – age) – kept internal for logic or comparison if needed,
// but we will use Tanaka for the main calculation as it is often cited as more precise for modern fitness.
// var maxHRStandard = 220 – age;
// Calculate Heart Rate Reserve (HRR)
var hrr = maxHR – rhr;
// Safety check: if RHR is higher than MHR (impossible)
if (hrr <= 0) {
alert("Your Resting Heart Rate cannot be higher than your estimated Max Heart Rate. Please check your inputs.");
return;
}
// 4. Update Summary Display
document.getElementById('display_mhr').innerHTML = Math.round(maxHR);
document.getElementById('display_hrr').innerHTML = Math.round(hrr);
document.getElementById('display_rhr_result').innerHTML = Math.round(rhr);
// 5. Calculate and Draw Zones Table (Karvonen: (HRR * %) + RHR)
var zones = [
{ name: "Zone 1", label: "Very Light", minPct: 0.50, maxPct: 0.60, colorClass: "zone-1", benefit: "Warm up, Recovery" },
{ name: "Zone 2", label: "Light", minPct: 0.60, maxPct: 0.70, colorClass: "zone-2", benefit: "Fat Burning, Endurance" },
{ name: "Zone 3", label: "Moderate", minPct: 0.70, maxPct: 0.80, colorClass: "zone-3", benefit: "Aerobic Fitness" },
{ name: "Zone 4", label: "Hard", minPct: 0.80, maxPct: 0.90, colorClass: "zone-4", benefit: "Anaerobic Threshold" },
{ name: "Zone 5", label: "Maximum", minPct: 0.90, maxPct: 1.00, colorClass: "zone-5", benefit: "Speed, Power" }
];
var tableHtml = "";
for (var i = 0; i < zones.length; i++) {
var z = zones[i];
var minBpm = Math.round((hrr * z.minPct) + rhr);
var maxBpm = Math.round((hrr * z.maxPct) + rhr);
tableHtml += "