Heart Rate Zones Calculator Garmin

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Garmin Heart Rate Zones Calculator

Heart Rate Reserve (%HRR) – Garmin Recommended Percentage of Max HR (%Max HR)

Your Garmin Personalized Zones

function calculateGarminZones() { var age = parseFloat(document.getElementById('calcAge').value); var restingHR = parseFloat(document.getElementById('calcRestHR').value); var maxHRInput = parseFloat(document.getElementById('calcMaxHR').value); var method = document.getElementById('calcMethod').value; var resultsDiv = document.getElementById('hrResults'); var outputDiv = document.getElementById('zonesOutput'); if (!age || age <= 0) { alert("Please enter a valid age."); return; } var maxHR = maxHRInput; if (isNaN(maxHR) || maxHR <= 0) { maxHR = 220 – age; } if (isNaN(restingHR) || restingHR <= 0) { restingHR = 60; // Default fallback for resting HR } var hrr = maxHR – restingHR; var zones = [ { name: "Zone 1: Warm-up", low: 0.50, high: 0.60, color: "#9e9e9e", desc: "Relaxed, easy pace; rhythmic breathing." }, { name: "Zone 2: Easy", low: 0.60, high: 0.70, color: "#4caf50", desc: "Comfortable pace; slightly deeper breathing, conversation possible." }, { name: "Zone 3: Aerobic", low: 0.70, high: 0.80, color: "#2196f3", desc: "Moderate pace; more difficult to hold conversation." }, { name: "Zone 4: Threshold", low: 0.80, high: 0.90, color: "#ff9800", desc: "Fast pace and a bit uncomfortable; breathing forceful." }, { name: "Zone 5: Maximum", low: 0.90, high: 1.00, color: "#f44336", desc: "Sprinting pace that is unsustainable for long periods." } ]; var html = ''; html += ''; for (var i = 0; i < zones.length; i++) { var lowBPM, highBPM; if (method === "hrr") { lowBPM = Math.round((hrr * zones[i].low) + restingHR); highBPM = Math.round((hrr * zones[i].high) + restingHR); } else { lowBPM = Math.round(maxHR * zones[i].low); highBPM = Math.round(maxHR * zones[i].high); } html += ''; html += ''; html += ''; html += ''; html += ''; } html += '
ZoneBPM RangeEffort
' + zones[i].name + '' + lowBPM + ' – ' + highBPM + ' bpm' + zones[i].desc + '
'; html += 'Max HR used: ' + maxHR + ' BPM | Resting HR: ' + restingHR + ' BPM'; outputDiv.innerHTML = html; resultsDiv.style.display = 'block'; }

Understanding Garmin Heart Rate Zones

If you use a Garmin Forerunner, Fenix, or Epix watch, you've likely seen the color-coded gauges during your runs or cycles. These zones determine the physiological effect of your training. By default, Garmin calculates these based on your maximum heart rate, but many athletes prefer using Heart Rate Reserve (HRR) for a more personalized experience.

The 5 Heart Rate Zones Explained

  • Zone 1 (50-60%): This is the "warm-up" zone. It's ideal for active recovery or the start of a long workout.
  • Zone 2 (60-70%): Known as the "Easy" or "Base" zone. This is where you build endurance and where your body becomes more efficient at burning fat as fuel.
  • Zone 3 (70-80%): The "Aerobic" zone. This improves your cardiovascular capacity. You'll breathe harder but can still maintain this for a while.
  • Zone 4 (80-90%): The "Threshold" zone. This is where you improve your anaerobic capacity and speed. It feels "comfortably hard."
  • Zone 5 (90-100%): The "Maximum" zone. This is for short bursts of high-intensity interval training (HIIT) or sprinting.

HRR vs. % Max HR: Which Should You Use?

Garmin watches allow you to toggle between different calculation methods. The standard % Max HR method is simple but doesn't account for your fitness level. The Heart Rate Reserve (HRR) method (also known as the Karvonen formula) uses your resting heart rate as a baseline.

Athletes with a very low resting heart rate often find that the % Max HR method puts their Zone 2 too low. Using HRR adjusts the zones upward, providing a more accurate representation of effort for fit individuals.

Real-World Example

Let's look at a 40-year-old runner with a resting heart rate of 50 BPM:

  1. Estimated Max HR: 220 – 40 = 180 BPM.
  2. Heart Rate Reserve (HRR): 180 (Max) – 50 (Rest) = 130 BPM.
  3. Zone 2 Calculation (HRR): (130 * 0.60) + 50 to (130 * 0.70) + 50 = 128 to 141 BPM.
  4. Zone 2 Calculation (Max HR %): 180 * 0.60 to 180 * 0.70 = 108 to 126 BPM.

As you can see, the HRR method provides a significantly different range that often feels more "correct" for active users.

How to Update Zones on Your Garmin Device

Once you have calculated your zones using the tool above, you can manually enter them into your device:

  1. Open the Garmin Connect app on your phone.
  2. Tap the More menu (or device icon).
  3. Select Garmin Devices and choose your watch.
  4. Go to User Profile > Heart Rate & Power Zones.
  5. Select Heart Rate and update the values for Zones 1 through 5.
  6. Sync your device.

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