Zone 2 Cardio Heart Rate by Age Calculator

Zone 2 Cardio Heart Rate Calculator

Optimize your aerobic base and fat-burning potential

Leave blank for the standard formula

Your Target Zone 2 Range:

Please enter a valid age.

What is Zone 2 Cardio?

Zone 2 training refers to exercise performed at a low-to-moderate intensity where your body primarily uses fat as its main fuel source through aerobic metabolism. It is often described as a "steady-state" pace where you can still maintain a conversation—the "Talk Test."

How We Calculate Your Zone

This calculator uses two distinct methods depending on the data you provide:

  • Standard Formula (Fox): Uses the classic (220 – Age) formula to determine Maximum Heart Rate (MHR) and targets 60-70% of that figure.
  • Karvonen Formula: If you provide your Resting Heart Rate (RHR), we use Heart Rate Reserve (HRR). This is generally considered more accurate because it accounts for your individual fitness level.

Training Examples by Age

Age Estimated Zone 2 (Standard)
25 Years Old 117 – 137 BPM
35 Years Old 111 – 130 BPM
45 Years Old 105 – 123 BPM
55 Years Old 99 – 116 BPM

Benefits of Zone 2 Training

Training in Zone 2 is the foundation of aerobic fitness. High-level athletes spend up to 80% of their time in this zone because it:

  • Increases Mitochondrial Density: Improves how efficiently your cells produce energy.
  • Improves Lactate Clearance: Helps you recover faster from high-intensity efforts.
  • Fat Oxidation: Maximizes the body's ability to burn fat for fuel.
  • Reduces Injury Risk: Provides cardiovascular benefits without the extreme stress of high-intensity interval training (HIIT).
function calculateZone2() { var age = parseFloat(document.getElementById("userAge").value); var rhr = parseFloat(document.getElementById("restingHR").value); var resultDiv = document.getElementById("zone2Result"); var errorBox = document.getElementById("errorBox"); var rangeDisplay = document.getElementById("hrRangeDisplay"); var methodText = document.getElementById("methodUsed"); if (isNaN(age) || age 120) { errorBox.style.display = "block"; resultDiv.style.display = "none"; return; } errorBox.style.display = "none"; var maxHR = 220 – age; var lowerBound, upperBound; if (!isNaN(rhr) && rhr > 30 && rhr < 120) { // Karvonen Formula var hrr = maxHR – rhr; lowerBound = Math.round((hrr * 0.60) + rhr); upperBound = Math.round((hrr * 0.70) + rhr); methodText.innerText = "Calculated using the Karvonen Formula (Heart Rate Reserve)."; } else { // Standard Formula lowerBound = Math.round(maxHR * 0.60); upperBound = Math.round(maxHR * 0.70); methodText.innerText = "Calculated using the Standard Percentage Method (60-70% of Max HR)."; } rangeDisplay.innerText = lowerBound + " – " + upperBound + " BPM"; resultDiv.style.display = "block"; }

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