Oxygen consumption (VO2) represents the amount of oxygen your body uses per minute to produce energy. This is a critical metric in physiology and sports science used to determine aerobic fitness and metabolic health. While VO2 max measures peak capacity, the VO2 rate (ml/min) tells you exactly how much fuel your cells are burning during specific tasks.
The Calculation Formula
The standard formula to calculate absolute VO2 in milliliters per minute (ml/min) is:
VO2 (ml/min) = MET Value × 3.5 × Body Weight (kg)
MET (Metabolic Equivalent): A unit that represents the energy cost of physical activities. 1 MET is the energy expended while sitting quietly.
3.5: This is the constant representing the average resting oxygen consumption (3.5 ml of oxygen per kilogram of body weight per minute).
Body Weight: Oxygen demand increases proportionally with the size of the active tissue (muscle mass).
Example Calculation
If a person weighs 80 kg and is jogging (approx. 8 METs):
VO2 = 8 METs × 3.5 × 80 kg = 2,240 ml/min.
This means the individual's body is processing 2.24 liters of oxygen every minute to sustain that level of effort.
Why Calculate VO2 in ml/min?
Calculating your oxygen consumption rate helps in several areas:
Caloric Expenditure: For every liter (1000 ml) of oxygen consumed, your body burns approximately 5 calories.
Training Intensity: Athletes use these metrics to stay within specific aerobic or anaerobic zones.
Health Monitoring: Lower-than-expected VO2 rates during exercise can indicate cardiovascular or respiratory inefficiencies.
var activitySelect = document.getElementById('activityMETs');
var customMETInput = document.getElementById('customMET');
activitySelect.onchange = function() {
if (activitySelect.value === 'custom') {
customMETInput.style.display = 'block';
} else {
customMETInput.style.display = 'none';
}
};
function calculateVO2() {
var weight = parseFloat(document.getElementById('bodyWeight').value);
var unit = document.getElementById('weightUnit').value;
var metValue = activitySelect.value === 'custom' ? parseFloat(customMETInput.value) : parseFloat(activitySelect.value);
var resultBox = document.getElementById('vo2-result-box');
var valueDisplay = document.getElementById('vo2-value');
var interpretation = document.getElementById('vo2-interpretation');
if (isNaN(weight) || weight <= 0) {
alert("Please enter a valid body weight.");
return;
}
if (isNaN(metValue) || metValue <= 0) {
alert("Please enter or select a valid MET value.");
return;
}
// Convert lbs to kg if necessary
var weightInKg = weight;
if (unit === 'lbs') {
weightInKg = weight * 0.453592;
}
// Formula: VO2 (ml/min) = MET * 3.5 * weight (kg)
var absoluteVO2 = metValue * 3.5 * weightInKg;
var roundedVO2 = Math.round(absoluteVO2);
var litersPerMin = (absoluteVO2 / 1000).toFixed(2);
var caloriesPerMin = (absoluteVO2 / 1000) * 5;
valueDisplay.innerHTML = roundedVO2.toLocaleString() + " ml/min";
interpretation.innerHTML = "At this intensity, your body consumes approximately " + litersPerMin + " liters of oxygen per minute. " +
"This metabolic rate results in burning roughly " + caloriesPerMin.toFixed(1) + " calories per minute.";
resultBox.style.display = 'block';
resultBox.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}