Best measured in the morning right after waking up.
Leave blank to estimate using (220 – Age).
Your Results
Estimated VO2 Max: — ml/kg/min
Fitness Level: —
*Estimation based on the Uth-Sørensen-Overgaard-Pedersen formula.
Understanding VO2 Max and Heart Rate
VO2 Max (Maximum Oxygen Volume) is widely considered the gold standard for measuring cardiovascular fitness and aerobic endurance. It represents the maximum amount of oxygen your body can utilize during intense exercise. While precise measurement requires a lab test with a mask and treadmill, you can estimate your VO2 Max effectively using your heart rate data.
The Heart Rate Ratio Formula
This calculator utilizes the Uth-Sørensen-Overgaard-Pedersen estimation method. This research established a direct correlation between the ratio of maximum heart rate to resting heart rate and VO2 Max capacity.
Resting Heart Rate (RHR): The number of times your heart beats per minute while you are at complete rest. The most accurate reading is taken immediately after waking up, before getting out of bed. Lower resting heart rates generally indicate better cardiovascular efficiency.
Maximum Heart Rate (HRmax): The highest number of beats per minute your heart can achieve during maximum physical exertion. If you do not know your exact HRmax from a stress test, it is commonly estimated using the formula 220 – Age.
Interpreting Your VO2 Max Score
Your VO2 Max score is measured in milliliters of oxygen used in one minute per kilogram of body weight (ml/kg/min). Higher scores indicate a greater ability to perform sustained aerobic physical activity.
General Reference Ranges (Men)
Excellent: > 50 ml/kg/min (varies by age)
Average: 35 – 45 ml/kg/min
Poor: < 30 ml/kg/min
General Reference Ranges (Women)
Excellent: > 45 ml/kg/min (varies by age)
Average: 30 – 40 ml/kg/min
Poor: < 25 ml/kg/min
Improving Your VO2 Max
To increase your VO2 Max, you must push your cardiovascular system to adapt. High-Intensity Interval Training (HIIT) is particularly effective. By alternating between short bursts of near-maximum effort (reaching 90-95% of your Max Heart Rate) and recovery periods, you can improve both your maximum oxygen uptake and your resting heart rate over time.
function calculateVo2Max() {
var gender = document.getElementById('vo2_gender').value;
var ageInput = document.getElementById('vo2_age').value;
var rhrInput = document.getElementById('vo2_resting_hr').value;
var mhrInput = document.getElementById('vo2_max_hr').value;
// Basic Validation
if (!ageInput || !rhrInput) {
alert("Please provide at least your Age and Resting Heart Rate.");
return;
}
var age = parseFloat(ageInput);
var rhr = parseFloat(rhrInput);
var mhr = 0;
// Determine Max Heart Rate
if (mhrInput) {
mhr = parseFloat(mhrInput);
} else {
// Estimate MHR if not provided
mhr = 220 – age;
// Fill the input for visibility (optional UX enhancement)
document.getElementById('vo2_max_hr').value = mhr;
}
if (isNaN(rhr) || isNaN(mhr) || isNaN(age)) {
alert("Please enter valid numbers.");
return;
}
if (rhr <= 0 || mhr <= 0 || age = mhr) {
alert("Resting Heart Rate cannot be higher than or equal to Maximum Heart Rate.");
return;
}
// Calculation: Uth-Sørensen-Overgaard-Pedersen estimation
// Formula: VO2max = 15 * (HRmax / HRrest)
var vo2Result = 15 * (mhr / rhr);
// Round to 1 decimal place
vo2Result = Math.round(vo2Result * 10) / 10;
// Display Number
document.getElementById('vo2_final_value').innerHTML = vo2Result;
// Determine Fitness Level
var rating = getFitnessRating(gender, age, vo2Result);
var ratingEl = document.getElementById('vo2_fitness_level');
ratingEl.innerHTML = rating.label;
ratingEl.className = 'vo2-category ' + rating.cssClass;
// Show Result Container
document.getElementById('vo2_result_container').style.display = 'block';
}
function getFitnessRating(gender, age, vo2) {
// Simplified Cooper Institute / ACSM normative data structure
// Returns object { label: string, cssClass: string }
var level = "Average";
var css = "cat-average";
if (gender === 'male') {
// Male Logic
if (age = 50) { level = "Excellent"; css = "cat-excellent"; }
else if (vo2 >= 40) { level = "Good"; css = "cat-good"; }
else if (vo2 >= 30) { level = "Average"; css = "cat-average"; }
else { level = "Poor"; css = "cat-poor"; }
} else if (age = 45) { level = "Excellent"; css = "cat-excellent"; }
else if (vo2 >= 35) { level = "Good"; css = "cat-good"; }
else if (vo2 >= 25) { level = "Average"; css = "cat-average"; }
else { level = "Poor"; css = "cat-poor"; }
} else {
if (vo2 >= 40) { level = "Excellent"; css = "cat-excellent"; }
else if (vo2 >= 30) { level = "Good"; css = "cat-good"; }
else if (vo2 >= 20) { level = "Average"; css = "cat-average"; }
else { level = "Poor"; css = "cat-poor"; }
}
} else {
// Female Logic
if (age = 45) { level = "Excellent"; css = "cat-excellent"; }
else if (vo2 >= 35) { level = "Good"; css = "cat-good"; }
else if (vo2 >= 25) { level = "Average"; css = "cat-average"; }
else { level = "Poor"; css = "cat-poor"; }
} else if (age = 40) { level = "Excellent"; css = "cat-excellent"; }
else if (vo2 >= 30) { level = "Good"; css = "cat-good"; }
else if (vo2 >= 20) { level = "Average"; css = "cat-average"; }
else { level = "Poor"; css = "cat-poor"; }
} else {
if (vo2 >= 35) { level = "Excellent"; css = "cat-excellent"; }
else if (vo2 >= 25) { level = "Good"; css = "cat-good"; }
else if (vo2 >= 17) { level = "Average"; css = "cat-average"; }
else { level = "Poor"; css = "cat-poor"; }
}
}
return { label: level, cssClass: css };
}