function calculateMaxHeartRate() {
var age = document.getElementById("age").value;
var resultDiv = document.getElementById("result");
// Clear previous results
resultDiv.innerHTML = "";
// Validate input
if (isNaN(age) || age <= 0) {
resultDiv.innerHTML = "Please enter a valid age (a positive number).";
return;
}
// Standard formula for Maximum Heart Rate (220 – age)
var maxHeartRate = 220 – age;
resultDiv.innerHTML =
"Your estimated maximum heart rate is:
" + maxHeartRate + " beats per minute (bpm)";
}
.heart-rate-calculator {
font-family: sans-serif;
max-width: 500px;
margin: 20px auto;
padding: 20px;
border: 1px solid #ccc;
border-radius: 8px;
box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.calculator-inputs .input-group {
margin-bottom: 15px;
}
.calculator-inputs label {
display: block;
margin-bottom: 5px;
font-weight: bold;
}
.calculator-inputs input[type="number"] {
width: calc(100% – 12px);
padding: 8px;
border: 1px solid #ccc;
border-radius: 4px;
}
.calculator-inputs button {
background-color: #4CAF50;
color: white;
padding: 10px 15px;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 16px;
transition: background-color 0.3s ease;
}
.calculator-inputs button:hover {
background-color: #45a049;
}
.calculator-result {
margin-top: 20px;
padding: 15px;
background-color: #f9f9f9;
border: 1px solid #eee;
border-radius: 4px;
}
.calculator-result p {
margin: 0;
font-size: 1.1em;
text-align: center;
}
.calculator-result strong {
color: #333;
}
Understanding Maximum Heart Rate
Your maximum heart rate (MHR) is the highest number of times your heart can beat in one minute during maximal physical exertion. It's a fundamental metric in understanding your cardiovascular fitness and designing effective exercise programs.
The Basic Formula
The most widely used and simplest formula to estimate your maximum heart rate is:
Maximum Heart Rate = 220 – Age
This formula, while straightforward, provides a good estimate for most individuals. For example:
- If you are 20 years old, your estimated maximum heart rate would be 220 – 20 = 200 beats per minute (bpm).
- If you are 40 years old, your estimated maximum heart rate would be 220 – 40 = 180 beats per minute (bpm).
- If you are 60 years old, your estimated maximum heart rate would be 220 – 60 = 160 beats per minute (bpm).
Why is Maximum Heart Rate Important?
Your MHR is crucial for:
- Setting Target Heart Rate Zones: Knowing your MHR allows you to calculate your target heart rate zones for different exercise intensities (e.g., fat burning, aerobic, anaerobic). These zones help ensure you're exercising effectively and safely.
- Monitoring Exercise Intensity: It provides a benchmark for how hard you are working during exercise.
- Assessing Fitness Levels: While not a sole indicator, changes in how easily you reach certain percentages of your MHR can suggest improvements in cardiovascular fitness over time.
Limitations of the Formula
It's important to remember that the "220 – Age" formula is an estimation. Individual heart rates can vary significantly due to genetics, fitness level, medications, and other physiological factors. Some people may naturally have a higher or lower maximum heart rate than this formula suggests.
For a more precise assessment, especially if you have underlying health conditions or are training for competitive events, consider consulting with a healthcare professional or a certified exercise physiologist who can conduct a supervised maximal exercise test.
However, for general fitness and moderate exercise planning, the "220 – Age" formula is a practical and accessible tool.