function calculateVO2Max() {
// 1. Get Inputs
var gender = document.getElementById('vo2_gender').value;
var age = parseFloat(document.getElementById('vo2_age').value);
var rhr = parseFloat(document.getElementById('vo2_rhr').value);
// 2. Validation
if (isNaN(age) || age 110) {
alert("Please enter a valid age between 10 and 110.");
return;
}
if (isNaN(rhr) || rhr 200) {
alert("Please enter a valid Resting Heart Rate (30-200 bpm).");
return;
}
// 3. Calculation Logic
// Formula: Uth-Sørensen-Overgaard-Pedersen estimation
// VO2max = 15.3 * (MHR / RHR)
// Calculate Max Heart Rate using Tanaka Formula (more accurate than 220-age)
// MHR = 208 – (0.7 * age)
var mhr = 208 – (0.7 * age);
// Calculate VO2 Max
var ratio = mhr / rhr;
var vo2Max = 15.3 * ratio;
// 4. Fitness Categorization (Generalized Cooper Institute data)
var fitnessLevel = "";
if (gender === 'male') {
if (age < 30) {
if (vo2Max < 35) fitnessLevel = "Poor";
else if (vo2Max < 43) fitnessLevel = "Fair";
else if (vo2Max < 50) fitnessLevel = "Good";
else if (vo2Max < 55) fitnessLevel = "Excellent";
else fitnessLevel = "Superior";
} else if (age < 40) {
if (vo2Max < 33) fitnessLevel = "Poor";
else if (vo2Max < 40) fitnessLevel = "Fair";
else if (vo2Max < 47) fitnessLevel = "Good";
else if (vo2Max < 52) fitnessLevel = "Excellent";
else fitnessLevel = "Superior";
} else if (age < 50) {
if (vo2Max < 30) fitnessLevel = "Poor";
else if (vo2Max < 36) fitnessLevel = "Fair";
else if (vo2Max < 43) fitnessLevel = "Good";
else if (vo2Max < 48) fitnessLevel = "Excellent";
else fitnessLevel = "Superior";
} else if (age < 60) {
if (vo2Max < 26) fitnessLevel = "Poor";
else if (vo2Max < 33) fitnessLevel = "Fair";
else if (vo2Max < 39) fitnessLevel = "Good";
else if (vo2Max < 44) fitnessLevel = "Excellent";
else fitnessLevel = "Superior";
} else {
if (vo2Max < 24) fitnessLevel = "Poor";
else if (vo2Max < 30) fitnessLevel = "Fair";
else if (vo2Max < 36) fitnessLevel = "Good";
else if (vo2Max < 40) fitnessLevel = "Excellent";
else fitnessLevel = "Superior";
}
} else { // Female
if (age < 30) {
if (vo2Max < 27) fitnessLevel = "Poor";
else if (vo2Max < 33) fitnessLevel = "Fair";
else if (vo2Max < 38) fitnessLevel = "Good";
else if (vo2Max < 43) fitnessLevel = "Excellent";
else fitnessLevel = "Superior";
} else if (age < 40) {
if (vo2Max < 26) fitnessLevel = "Poor";
else if (vo2Max < 31) fitnessLevel = "Fair";
else if (vo2Max < 36) fitnessLevel = "Good";
else if (vo2Max < 41) fitnessLevel = "Excellent";
else fitnessLevel = "Superior";
} else if (age < 50) {
if (vo2Max < 24) fitnessLevel = "Poor";
else if (vo2Max < 29) fitnessLevel = "Fair";
else if (vo2Max < 33) fitnessLevel = "Good";
else if (vo2Max < 37) fitnessLevel = "Excellent";
else fitnessLevel = "Superior";
} else if (age < 60) {
if (vo2Max < 22) fitnessLevel = "Poor";
else if (vo2Max < 27) fitnessLevel = "Fair";
else if (vo2Max < 31) fitnessLevel = "Good";
else if (vo2Max < 35) fitnessLevel = "Excellent";
else fitnessLevel = "Superior";
} else {
if (vo2Max < 20) fitnessLevel = "Poor";
else if (vo2Max < 24) fitnessLevel = "Fair";
else if (vo2Max < 28) fitnessLevel = "Good";
else if (vo2Max < 32) fitnessLevel = "Excellent";
else fitnessLevel = "Superior";
}
}
// 5. Display Results
document.getElementById('vo2_result').style.display = 'block';
document.getElementById('vo2_final_value').innerText = vo2Max.toFixed(1) + " mL/kg/min";
document.getElementById('vo2_category').innerText = "Fitness Level: " + fitnessLevel;
document.getElementById('vo2_mhr_val').innerText = Math.round(mhr) + " bpm";
document.getElementById('vo2_ratio_val').innerText = ratio.toFixed(2);
}
How to Calculate VO2 Max from Resting Heart Rate
Your VO2 Max is considered the gold standard for measuring cardiovascular fitness. It represents the maximum amount of oxygen your body can utilize during intense exercise. While a clinical lab test involving a mask and treadmill is the most accurate method, researchers have developed reliable formulas to estimate VO2 Max using simple metrics like your Resting Heart Rate (RHR).
This calculator uses the Uth-Sørensen-Overgaard-Pedersen estimation method, which compares your maximum heart rate to your resting heart rate. The underlying physiology implies that individuals with better cardiovascular conditioning typically have a lower resting heart rate and a larger "reserve" between their resting and maximum rates.
The Formula Used
The calculation performed by this tool is based on the following equation:
VO2 Max ≈ 15.3 × (MHR / RHR)
Where:
MHR (Maximum Heart Rate): Estimated using the Tanaka formula: 208 – (0.7 × Age).
RHR (Resting Heart Rate): Your heart rate measured while completely at rest.
How to Measure Resting Heart Rate Accurately
To ensure the results of this VO2 Max calculator are accurate, your input for Resting Heart Rate must be precise. Follow these steps:
Timing: The best time to measure is immediately after waking up in the morning, before getting out of bed or drinking coffee.
Position: Remain lying down or sit quietly in a chair for at least 5 minutes before measuring.
Technique: Place two fingers on your wrist (radial artery) or neck (carotid artery). Count the beats for 60 seconds, or count for 30 seconds and multiply by 2.
Interpreting Your Results
Superior / Excellent: Indicates a highly efficient cardiovascular system, typical of endurance athletes.
Good / Fair: Represents average to slightly above-average fitness. You have a solid foundation but room for improvement.
Poor: Suggests the cardiovascular system may be deconditioned. Consult a healthcare provider before starting a rigorous exercise program.
Improving Your VO2 Max
Increasing your VO2 Max requires consistent aerobic exercise. High-Intensity Interval Training (HIIT) is often cited as one of the most effective ways to boost VO2 Max quickly. Activities like running, cycling, rowing, and swimming, performed at varying intensities, force the heart to pump more efficiently and muscles to utilize oxygen more effectively.