.metabolic-calc-container {
max-width: 600px;
margin: 0 auto;
padding: 2rem;
background: #ffffff;
border-radius: 12px;
box-shadow: 0 4px 20px rgba(0,0,0,0.08);
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}
.metabolic-calc-container h2 {
color: #2c3e50;
text-align: center;
margin-bottom: 1.5rem;
}
.form-group {
margin-bottom: 1.2rem;
}
.form-group label {
display: block;
margin-bottom: 0.5rem;
color: #555;
font-weight: 600;
}
.form-group input {
width: 100%;
padding: 12px;
border: 1px solid #ddd;
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
}
.form-group input:focus {
border-color: #e91e63;
outline: none;
box-shadow: 0 0 0 3px rgba(233, 30, 99, 0.1);
}
.calc-btn {
width: 100%;
padding: 14px;
background-color: #e91e63;
color: white;
border: none;
border-radius: 6px;
font-size: 18px;
font-weight: bold;
cursor: pointer;
transition: background-color 0.2s;
}
.calc-btn:hover {
background-color: #c2185b;
}
#result-box {
margin-top: 2rem;
padding: 1.5rem;
background-color: #fce4ec;
border-radius: 8px;
display: none;
text-align: center;
border-left: 5px solid #e91e63;
}
.result-value {
font-size: 2.5rem;
font-weight: 800;
color: #e91e63;
margin: 10px 0;
}
.result-label {
color: #333;
font-weight: 500;
}
.metrics-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 10px;
margin-top: 15px;
text-align: left;
}
.metric-item {
background: white;
padding: 10px;
border-radius: 4px;
font-size: 0.9rem;
}
/* Article Styles */
.content-article {
max-width: 800px;
margin: 40px auto;
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
line-height: 1.6;
color: #333;
}
.content-article h2 {
color: #e91e63;
border-bottom: 2px solid #f8bbd0;
padding-bottom: 10px;
margin-top: 30px;
}
.content-article h3 {
color: #880e4f;
}
.content-article p {
margin-bottom: 15px;
}
.content-article ul {
margin-bottom: 20px;
padding-left: 20px;
}
.content-article li {
margin-bottom: 8px;
}
.highlight-box {
background: #f5f5f5;
padding: 20px;
border-radius: 8px;
margin: 20px 0;
}
function calculateMetabolicAge() {
// Get input values
var age = parseFloat(document.getElementById('chronoAge').value);
var height = parseFloat(document.getElementById('heightCm').value);
var weight = parseFloat(document.getElementById('weightKg').value);
var waist = parseFloat(document.getElementById('waistCm').value);
var hr = parseFloat(document.getElementById('restingHR').value);
// Validation
if (!age || !height || !weight || !waist || !hr) {
alert("Please fill in all fields to calculate your metabolic age.");
return;
}
// 1. Calculate Basal Metabolic Rate (BMR) – Mifflin-St Jeor Equation for Females
// Formula: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
var bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161;
// 2. Calculate BMI
var heightM = height / 100;
var bmi = weight / (heightM * heightM);
// 3. Calculate Waist-to-Height Ratio (WHtR)
var whtr = waist / height;
// 4. Determine Metabolic Age Offset based on Health Markers
// This logic approximates metabolic health relative to chronological age
var ageAdjustment = 0;
// BMI Adjustment
if (bmi = 18.5 && bmi = 25 && bmi <= 29.9) ageAdjustment += 3; // Overweight
else ageAdjustment += 6; // Obese
// Waist-to-Height Ratio Adjustment (Specific for Females)
// Healthy range for women is generally < 0.5
if (whtr = 0.42 && whtr = 0.50 && whtr = 0.54 && whtr <= 0.58) ageAdjustment += 4; // Poor
else ageAdjustment += 7; // Very Poor
// Resting Heart Rate Adjustment
// Lower resting HR generally indicates better cardiovascular fitness
if (hr = 60 && hr = 71 && hr = 81 && hr <= 90) ageAdjustment += 3; // Below Average
else ageAdjustment += 5; // Poor
// 5. Calculate Final Metabolic Age
var metabolicAge = age + ageAdjustment;
// Ensure metabolic age doesn't go below reasonable biological limits (e.g. 12)
if (metabolicAge < 12) metabolicAge = 12;
// 6. Determine Status String
var diff = metabolicAge – age;
var diffString = "";
var status = "";
if (diff < -5) {
diffString = "Excellent! You are roughly " + Math.abs(diff) + " years younger metabolically.";
status = "Peak Performance";
} else if (diff <= 0) {
diffString = "Good work. You are " + Math.abs(diff) + " years younger metabolically.";
status = "Healthy";
} else if (diff <= 5) {
diffString = "You are roughly " + diff + " years older metabolically.";
status = "Needs Improvement";
} else {
diffString = "Warning: You are " + diff + " years older metabolically.";
status = "At Risk";
}
// Display Results
document.getElementById('metabolicAgeResult').innerHTML = Math.round(metabolicAge) + " Years";
document.getElementById('ageDifference').innerHTML = diffString;
document.getElementById('bmrResult').innerHTML = Math.round(bmr);
document.getElementById('bmiResult').innerHTML = bmi.toFixed(1);
document.getElementById('whtrResult').innerHTML = whtr.toFixed(2);
document.getElementById('statusResult').innerHTML = status;
document.getElementById('result-box').style.display = "block";
}
Understanding Your Metabolic Age
Metabolic age is a health metric that compares your Basal Metabolic Rate (BMR) against the average BMR of individuals in your chronological age group. For women, this calculation is particularly nuanced due to differences in muscle mass, hormonal profiles, and essential fat distribution compared to men.
If your metabolic age is lower than your actual age, it suggests that your body is in good physical condition, burning calories efficiently much like a younger person would. Conversely, a metabolic age higher than your chronological age indicates that your metabolic rate is slower than average, which may be linked to lower muscle mass, higher visceral fat, or hormonal imbalances.
How This Calculator Works for Females
While a clinical metabolic age assessment typically involves bioelectrical impedance analysis (BIA) to measure body composition precisely, this online calculator uses a reliable "Health Marker Proxy" method. It evaluates four key biological data points:
- BMR (Basal Metabolic Rate): Calculated using the Mifflin-St Jeor equation specifically modified for females:
(10 × weight) + (6.25 × height) - (5 × age) - 161.
- Waist-to-Height Ratio (WHtR): A superior predictor of metabolic risk for women compared to BMI alone, as it accounts for abdominal adiposity (belly fat).
- Resting Heart Rate: A strong indicator of cardiovascular efficiency and aerobic fitness.
- BMI (Body Mass Index): A general screen for weight categories relative to height.
Why Muscle Mass Matters for Women
The single most effective way for a woman to lower her metabolic age is to increase lean muscle tissue. Muscle is metabolically active, meaning it burns calories even when you are sleeping. As women age, natural muscle loss (sarcopenia) slows down BMR. Strength training counteracts this, effectively "reversing" metabolic aging.
Interpreting Your Results
Result: Lower than Chronological Age
This is the goal. It indicates high metabolic efficiency, likely driven by good muscle tone and low visceral fat.
Result: Higher than Chronological Age
This serves as a wake-up call. It suggests your metabolism is sluggish. To reverse this, focus on:
- Increasing protein intake to support muscle repair.
- Incorporating resistance training 2-3 times per week.
- Improving sleep quality (cortisol regulation).
- Managing stress levels, which can negatively impact female metabolic hormones.
Frequently Asked Questions
Does metabolic age change during menopause?
Yes. Due to the drop in estrogen, women often experience a reduction in muscle mass and a redistribution of fat to the abdominal area, which can increase metabolic age. Targeted exercise is crucial during this phase.
How accurate is this calculator?
This tool provides an estimate based on statistical averages of health markers. For a medical-grade diagnosis, consult a professional for a metabolic ward study or DEXA scan.