How to Calculate Heart Rate Zones

Understanding and Calculating Your Heart Rate Zones

Heart rate zones are ranges of your heart rate, expressed as a percentage of your maximum heart rate, that correspond to different levels of exercise intensity. Understanding these zones can help you tailor your training to achieve specific fitness goals, whether it's improving cardiovascular health, increasing endurance, or boosting performance.

What is Maximum Heart Rate?

Your maximum heart rate (MHR) is the highest number of times your heart can beat per minute during maximal physical exertion. A common and simple way to estimate your MHR is using the formula: 220 – your age. While this is a general estimate, individual MHR can vary.

The Different Heart Rate Zones

Most training plans utilize five heart rate zones, each targeting different physiological benefits:

• Zone 1 (Very Light): 50-60% of MHR. This zone is for active recovery and is typically used after intense workouts.
• Zone 2 (Light): 60-70% of MHR. This is your aerobic zone, great for building a base level of fitness and improving endurance.
• Zone 3 (Moderate): 70-80% of MHR. This zone improves your aerobic fitness and starts to increase your lactate threshold.
• Zone 4 (Hard): 80-90% of MHR. This is your anaerobic zone. Training here improves speed and power, and increases your lactate threshold significantly.
• Zone 5 (Maximum): 90-100% of MHR. This zone is for very short, high-intensity bursts. It's challenging and typically used for interval training and sprinting.

How to Calculate Your Zones

To calculate your heart rate zones, you first need to estimate your maximum heart rate. Once you have that number, you can apply the percentages for each zone. Our calculator below does this for you!

Heart Rate Zone Calculator

function calculateHeartRateZones() { var ageInput = document.getElementById("age"); var age = parseFloat(ageInput.value); var resultDiv = document.getElementById("result"); var maxHeartRateSpan = document.getElementById("maxHeartRate"); var zone1Span = document.getElementById("zone1"); var zone2Span = document.getElementById("zone2"); var zone3Span = document.getElementById("zone3"); var zone4Span = document.getElementById("zone4"); var zone5Span = document.getElementById("zone5"); // Clear previous results maxHeartRateSpan.textContent = "–"; zone1Span.textContent = "–"; zone2Span.textContent = "–"; zone3Span.textContent = "–"; zone4Span.textContent = "–"; zone5Span.textContent = "–"; if (isNaN(age) || age <= 0) { alert("Please enter a valid age greater than 0."); return; } // Estimate Maximum Heart Rate (MHR) var maxHeartRate = 220 – age; // Calculate Heart Rate Zones var zone1_50 = Math.round(maxHeartRate * 0.50); var zone1_60 = Math.round(maxHeartRate * 0.60); var zone2_60 = Math.round(maxHeartRate * 0.60); var zone2_70 = Math.round(maxHeartRate * 0.70); var zone3_70 = Math.round(maxHeartRate * 0.70); var zone3_80 = Math.round(maxHeartRate * 0.80); var zone4_80 = Math.round(maxHeartRate * 0.80); var zone4_90 = Math.round(maxHeartRate * 0.90); var zone5_90 = Math.round(maxHeartRate * 0.90); var zone5_100 = Math.round(maxHeartRate * 1.00); // Display Results maxHeartRateSpan.textContent = maxHeartRate; zone1Span.textContent = zone1_50 + " – " + zone1_60; zone2Span.textContent = zone2_60 + " – " + zone2_70; zone3Span.textContent = zone3_70 + " – " + zone3_80; zone4Span.textContent = zone4_80 + " – " + zone4_90; zone5Span.textContent = zone5_90 + " – " + zone5_100; }