Heart Rate Training Calculator

Heart Rate Training Zone Calculator

Your Personalized Target Zones

Based on the Karvonen Formula (Heart Rate Reserve method).

function calculateHRZones() { var age = parseFloat(document.getElementById('userAge').value); var rhr = parseFloat(document.getElementById('restingHR').value); if (isNaN(age) || isNaN(rhr) || age <= 0 || rhr <= 0) { alert("Please enter valid numbers for age and resting heart rate."); return; } var maxHR = 220 – age; var hrr = maxHR – rhr; // Heart Rate Reserve var zones = [ { name: "Zone 1: Recovery (50-60%)", low: 0.50, high: 0.60, color: "#3498db", desc: "Easy pace, active recovery, and warm-ups." }, { name: "Zone 2: Endurance (60-70%)", low: 0.60, high: 0.70, color: "#2ecc71", desc: "Fat metabolism, base building, and long runs." }, { name: "Zone 3: Aerobic (70-80%)", low: 0.70, high: 0.80, color: "#f1c40f", desc: "Improving cardiovascular fitness and stamina." }, { name: "Zone 4: Anaerobic (80-90%)", low: 0.80, high: 0.90, color: "#e67e22", desc: "Speed endurance and high-intensity capacity." }, { name: "Zone 5: VO2 Max (90-100%)", low: 0.90, high: 1.00, color: "#e74c3c", desc: "Maximum effort, short sprints, and peak performance." } ]; var resultsDiv = document.getElementById('hrResults'); var grid = document.getElementById('zoneGrid'); grid.innerHTML = ""; for (var i = 0; i < zones.length; i++) { var zone = zones[i]; var lowBPM = Math.round((hrr * zone.low) + rhr); var highBPM = Math.round((hrr * zone.high) + rhr); var card = document.createElement('div'); card.style.padding = "15px"; card.style.borderRadius = "8px"; card.style.backgroundColor = "white"; card.style.borderLeft = "6px solid " + zone.color; card.style.boxShadow = "0 2px 4px rgba(0,0,0,0.05)"; card.innerHTML = "" + zone.name + "" + "" + lowBPM + " – " + highBPM + " BPM" + "" + zone.desc + ""; grid.appendChild(card); } resultsDiv.style.display = "block"; }

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Mastering Your Fitness with the Heart Rate Training Calculator

Heart rate training uses your heart's beats per minute (BPM) as a guide to ensure you are working at the right intensity level for your specific fitness goals. Whether you want to burn fat, increase your endurance, or improve your sprinting speed, knowing your target heart rate zones is essential.

What is the Karvonen Formula?

Unlike simple calculations that only look at age, this calculator uses the Karvonen Formula. This method is widely considered more accurate because it incorporates your Heart Rate Reserve (HRR). HRR is the difference between your maximum heart rate and your resting heart rate. By including your resting heart rate, the calculation adapts to your current level of cardiovascular fitness.

The Five Intensity Zones Explained

• Zone 1 (50-60%): Very light intensity. Ideal for warming up, cooling down, or active recovery days. It helps improve circulation without stressing the body.
• Zone 2 (60-70%): The "Fat Burning" zone. This is a sustainable pace where your body primarily uses fat for fuel. It is the foundation for long-distance endurance athletes.
• Zone 3 (70-80%): The Aerobic zone. Here, you are breathing harder but can still speak in short sentences. This zone improves your heart's efficiency and lung capacity.
• Zone 4 (80-90%): The Anaerobic zone. This is high intensity. You will develop lactate threshold and the ability to sustain speed for longer periods.
• Zone 5 (90-100%): Red line / Maximum effort. Used for HIIT (High-Intensity Interval Training) and short sprints. This builds peak power and VO2 Max.

Real-World Training Example

Imagine a 35-year-old individual with a resting heart rate of 60 BPM. Using the Heart Rate Training Calculator:

• Estimated Max HR: 185 BPM (220 – 35)
• Heart Rate Reserve: 125 BPM (185 – 60)
• Zone 2 Target (60-70%): 135 to 148 BPM.

If this person wants to go for a "base building" run, they should keep their heart rate between 135 and 148 BPM. If their heart rate climbs to 160 BPM, they have moved into Zone 3 and are no longer training for optimal fat metabolism.

Tips for Accurate Results

To get the most out of this calculator, ensure your Resting Heart Rate (RHR) is accurate. The best time to measure RHR is first thing in the morning, immediately after waking up, while still in bed. Measure it for three consecutive mornings and take the average for the most precise data input.