function calculateGelishMHR() {
// Get Input
var ageInput = document.getElementById('gelish_age');
var age = parseFloat(ageInput.value);
// Validation
if (isNaN(age) || age 120) {
alert("Please enter a valid age between 1 and 120.");
return;
}
// Gelish Formula Calculation
// Formula: 206.9 – (0.67 x Age)
var mhr = 206.9 – (0.67 * age);
var mhrRounded = Math.round(mhr);
// Calculate Zones
// Zone 1: 50-60%
var z1_min = Math.round(mhr * 0.50);
var z1_max = Math.round(mhr * 0.60);
// Zone 2: 60-70%
var z2_min = Math.round(mhr * 0.60);
var z2_max = Math.round(mhr * 0.70);
// Zone 3: 70-80%
var z3_min = Math.round(mhr * 0.70);
var z3_max = Math.round(mhr * 0.80);
// Zone 4: 80-90%
var z4_min = Math.round(mhr * 0.80);
var z4_max = Math.round(mhr * 0.90);
// Zone 5: 90-100%
var z5_min = Math.round(mhr * 0.90);
var z5_max = mhrRounded;
// Display Main Result
document.getElementById('gelish_mhr_display').innerHTML = mhrRounded + " BPM";
// Build Table HTML
var tableHtml = ";
tableHtml += '
Calculating your Maximum Heart Rate (MHR) is the cornerstone of effective cardiovascular training. While the traditional "220 minus age" formula has been the standard for decades, recent sports science suggests it may not be accurate for everyone. The Gelish Formula (more formally known as the Gellish equation) offers a more precise way to estimate your MHR based on age.
Whether you are a seasoned athlete looking to refine your heart rate zones or a beginner ensuring you are exercising safely, using the correct formula is crucial for setting appropriate training intensities.
What is the Gelish Formula?
The Gelish formula is a non-linear regression equation derived from longitudinal studies on age and heart rate. It is generally considered more accurate than the standard Fox formula (220 – age), particularly for individuals over the age of 30.
MHR = 206.9 – (0.67 × Age)
This formula assumes that maximum heart rate declines at a slightly different rate than simply one beat per year. By using a multiplier of 0.67 against your age, the Gelish equation smooths out the decline, providing a result that often feels more realistic for active adults.
Gelish vs. Traditional Methods
Why switch to the Gelish formula? The traditional "220 – age" calculation is simple math, but human physiology is rarely that linear.
Standard (Fox) Formula: Often underestimates MHR for older adults and overestimates it for younger populations.
Gelish Formula: Provides a tighter correlation to clinical stress test results across a wider age demographic.
For example, for a 50-year-old individual:
Standard: 220 – 50 = 170 BPM
Gelish: 206.9 – (0.67 × 50) = 173.4 BPM
While a difference of 3-4 beats might seem small, it shifts your training zones. This ensures that when you are aiming for "Zone 2" fat burning or "Zone 4" threshold training, you are actually in the correct physiological state.
How to Use Your Results
Once you have calculated your predicted maximum heart rate using the tool above, apply it to the five standard training zones to structure your workouts:
Zone 1 (Warm Up): Ideal for recovery days and warming up. Helps with blood flow without fatigue.
Zone 2 (Fat Burn): The "conversational pace." This builds your aerobic base and teaches the body to utilize fat as fuel.
Zone 3 (Aerobic): Moderate intensity. This improves blood circulation and skeletal muscle efficiency.
Zone 4 (Anaerobic): High intensity. You will breathe hard. This improves lactate threshold and speed endurance.
Zone 5 (Maximum): All-out effort for short bursts. Used primarily for interval training to increase top-end speed and power.
Note: While the Gelish formula is a robust statistical estimate, the only way to determine your true maximum heart rate with 100% accuracy is through a graded exercise stress test supervised by a professional.