Apple Watch Heart Rate Zone Calculator
function calculateHeartRateZones() {
var maxHeartRateInput = document.getElementById("maxHeartRate");
var resultDiv = document.getElementById("result");
// Clear previous results
resultDiv.innerHTML = "";
// Validate input
var maxHeartRate = parseFloat(maxHeartRateInput.value);
if (isNaN(maxHeartRate) || maxHeartRate <= 0) {
resultDiv.innerHTML = "Please enter a valid maximum heart rate (a positive number).";
return;
}
// Define heart rate zones based on percentages of Max Heart Rate
// These are common zone definitions, but can vary.
// Zone 1: Very Light (50-60% of Max HR)
// Zone 2: Light (60-70% of Max HR)
// Zone 3: Moderate (70-80% of Max HR)
// Zone 4: Hard (80-90% of Max HR)
// Zone 5: Maximum (90-100% of Max HR)
var zone1Min = Math.round(maxHeartRate * 0.50);
var zone1Max = Math.round(maxHeartRate * 0.60);
var zone2Min = Math.round(maxHeartRate * 0.61); // Start from 61% to avoid overlap
var zone2Max = Math.round(maxHeartRate * 0.70);
var zone3Min = Math.round(maxHeartRate * 0.71); // Start from 71%
var zone3Max = Math.round(maxHeartRate * 0.80);
var zone4Min = Math.round(maxHeartRate * 0.81); // Start from 81%
var zone4Max = Math.round(maxHeartRate * 0.90);
var zone5Min = Math.round(maxHeartRate * 0.91); // Start from 91%
var zone5Max = maxHeartRate; // Up to 100%
var htmlOutput = "
Your Heart Rate Zones:
";
htmlOutput += "
";
htmlOutput += "
Zone 1 (Very Light): " + zone1Min + " – " + zone1Max + " bpm
";
htmlOutput += "
Zone 2 (Light): " + zone2Min + " – " + zone2Max + " bpm
";
htmlOutput += "
Zone 3 (Moderate): " + zone3Min + " – " + zone3Max + " bpm
";
htmlOutput += "
Zone 4 (Hard): " + zone4Min + " – " + zone4Max + " bpm
";
htmlOutput += "
Zone 5 (Maximum): " + zone5Min + " – " + zone5Max + " bpm
";
htmlOutput += "
";
resultDiv.innerHTML = htmlOutput;
}
.calculator-wrapper {
font-family: sans-serif;
border: 1px solid #ddd;
padding: 20px;
border-radius: 8px;
max-width: 500px;
margin: 20px auto;
background-color: #f9f9f9;
}
.calculator-wrapper h2 {
text-align: center;
color: #333;
margin-bottom: 20px;
}
.calculator-form {
display: flex;
flex-direction: column;
gap: 15px;
}
.form-field {
display: flex;
flex-direction: column;
}
.form-field label {
margin-bottom: 5px;
font-weight: bold;
color: #555;
}
.form-field input[type="number"] {
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
}
.calculator-form button {
padding: 12px 20px;
background-color: #007bff;
color: white;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 16px;
transition: background-color 0.3s ease;
}
.calculator-form button:hover {
background-color: #0056b3;
}
.calculator-result {
margin-top: 25px;
padding: 15px;
border: 1px solid #eee;
border-radius: 4px;
background-color: #fff;
}
.calculator-result h3 {
margin-top: 0;
color: #444;
border-bottom: 1px solid #eee;
padding-bottom: 10px;
margin-bottom: 15px;
}
.zone-details {
display: grid;
grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
gap: 10px;
}
.zone {
padding: 8px;
border-radius: 4px;
font-size: 14px;
color: #333;
}
.zone-1 { background-color: #d4edda; border-left: 5px solid #28a745; } /* Greenish */
.zone-2 { background-color: #fff3cd; border-left: 5px solid #ffc107; } /* Yellowish */
.zone-3 { background-color: #cfe2f3; border-left: 5px solid #17a2b8; } /* Bluish */
.zone-4 { background-color: #f8d7da; border-left: 5px solid #dc3545; } /* Reddish */
.zone-5 { background-color: #e2e3e5; border-left: 5px solid #6c757d; } /* Grayish */
Understanding Your Apple Watch Heart Rate Zones
Your Apple Watch, like many fitness trackers, uses heart rate zones to help you understand the intensity of your workouts and tailor your training for specific goals. These zones are typically based on a percentage of your maximum heart rate (MHR). By staying within certain zones, you can optimize your training for endurance, fat burning, cardiovascular fitness, or recovery.
What are Heart Rate Zones?
Heart rate zones divide your potential heart rate range into different intensity levels. Each zone corresponds to a different physiological effect:
- Zone 1 (Very Light): 50-60% of Max HR. This is your recovery pace. It's great for warm-ups, cool-downs, or very light active recovery days. You should be able to hold a full conversation easily.
- Zone 2 (Light): 60-70% of Max HR. This is your base endurance pace. You can sustain this for long periods, and it's excellent for building aerobic fitness and burning fat efficiently. Conversation is still possible but requires more effort.
- Zone 3 (Moderate): 70-80% of Max HR. This is often referred to as the "tempo" or "aerobic" zone. Your breathing becomes heavier, and you can speak in short sentences. This zone improves your cardiovascular fitness and endurance.
- Zone 4 (Hard): 80-90% of Max HR. This is your threshold pace, pushing your anaerobic capacity. It's challenging to speak more than a word or two. Training here significantly improves your speed and power and raises your lactate threshold.
- Zone 5 (Maximum): 90-100% of Max HR. This is maximal effort. You can only sustain this for very short bursts. It's used for very high-intensity interval training (HIIT) to maximize your VO2 max and anaerobic power.
Estimating Your Maximum Heart Rate
The most common (though simplified) formula to estimate your maximum heart rate is 220 – Your Age. For example, a 30-year-old person would have an estimated MHR of 190 bpm (220 – 30 = 190).
However, this is just an estimate. Your actual MHR can vary. For a more accurate MHR, a professionally supervised exercise stress test is recommended. Your Apple Watch also learns your fitness level over time and may provide more personalized estimates.
How to Use This Calculator
To find your personal heart rate zones, simply input your estimated maximum heart rate (in beats per minute, bpm) into the calculator above. It will then show you the bpm ranges for each of the five standard heart rate zones.
Example Calculation
Let's say you are 45 years old. Using the 220 – Age formula, your estimated maximum heart rate is 175 bpm (220 – 45 = 175).
If you input 175 bpm into the calculator, you would get:
- Zone 1 (Very Light): 88 – 105 bpm
- Zone 2 (Light): 107 – 123 bpm
- Zone 3 (Moderate): 124 – 140 bpm
- Zone 4 (Hard): 141 – 158 bpm
- Zone 5 (Maximum): 159 – 175 bpm
Using Heart Rate Zones with Your Apple Watch
Once you know your zones, you can use them to guide your workouts. Many workout types on your Apple Watch can display your current heart rate and target zones. Pay attention to the zone you're in during your exercise to ensure you're training effectively for your goals, whether it's building a strong aerobic base, improving speed, or recovering from a tough session.