Leave blank for standard calculation, or enter for Karvonen precision.
Estimated Max Heart Rate (MHR):–
Calculation Method:–
Vigorous Intensity Zone (70% – 85%)0 – 0 BPM
function calculateVigorousZone() {
// 1. Get Input Values
var ageInput = document.getElementById('vhr_age');
var rhrInput = document.getElementById('vhr_rhr');
var resultsDiv = document.getElementById('vhr_results');
var age = parseFloat(ageInput.value);
var rhr = parseFloat(rhrInput.value);
// 2. Validate Age
if (isNaN(age) || age 120) {
alert("Please enter a valid age between 1 and 120.");
return;
}
// 3. Define Constants (Vigorous = 70% to 85%)
var intensityMin = 0.70;
var intensityMax = 0.85;
// 4. Calculate Max Heart Rate (Standard Formula)
var maxHeartRate = 220 – age;
var targetMin, targetMax, methodText;
// 5. Determine Method (Standard vs Karvonen)
if (!isNaN(rhr) && rhr > 20 && rhr < 200) {
// Karvonen Method: Target HR = ((MHR − RHR) × %Intensity) + RHR
var heartRateReserve = maxHeartRate – rhr;
targetMin = (heartRateReserve * intensityMin) + rhr;
targetMax = (heartRateReserve * intensityMax) + rhr;
methodText = "Karvonen Formula";
} else {
// Standard Method: Target HR = MHR * %Intensity
targetMin = maxHeartRate * intensityMin;
targetMax = maxHeartRate * intensityMax;
methodText = "Standard Age-Based";
}
// 6. Round Results
targetMin = Math.round(targetMin);
targetMax = Math.round(targetMax);
// 7. Update HTML
document.getElementById('vhr_display_mhr').innerHTML = maxHeartRate + " bpm";
document.getElementById('vhr_display_method').innerHTML = methodText;
document.getElementById('vhr_display_zone').innerHTML = targetMin + " – " + targetMax + " BPM";
// 8. Show Results
resultsDiv.style.display = "block";
}
Understanding Vigorous Intensity Exercise
Achieving a vigorous heart rate is a key component of cardiovascular fitness. Unlike moderate activity, vigorous exercise pushes your body to approximately 70% to 85% of its maximum capacity. This calculator helps you define that specific "Vigorous Zone" so you can train effectively and safely.
What is Vigorous Activity?
According to the American Heart Association and the CDC, vigorous activity is defined as physical exertion that significantly increases your heart rate and breathing. A simple test is the "Talk Test": if you are exercising vigorously, you will not be able to say more than a few words without pausing for breath.
Examples of vigorous activities include:
Running or jogging
Swimming laps
Cycling faster than 10 miles per hour
Jumping rope
High-Intensity Interval Training (HIIT)
Competitive sports like soccer or basketball
Why Target the Vigorous Zone?
Training in the vigorous zone (70-85% of your Max Heart Rate) offers distinct physiological benefits compared to lower intensity zones:
Efficiency: Vigorous exercise provides similar health benefits to moderate exercise in roughly half the time. The recommended guideline is 75 minutes of vigorous activity per week, compared to 150 minutes of moderate activity.
Increased VO2 Max: Improves your body's ability to consume and utilize oxygen.
Calorie Burn: Burns more calories per minute and can increase the "afterburn" effect (EPOC).
Heart Health: Strengthens the heart muscle and improves blood vessel elasticity.
Calculation Methods Explained
This calculator utilizes two primary methods depending on the data you provide:
1. Standard Age-Predicted Method
The most common way to estimate heart rate zones. It first calculates your Maximum Heart Rate (MHR) using the formula 220 – Age. It then calculates percentages of that maximum. While simple, it does not account for individual fitness levels.
2. The Karvonen Formula
If you enter your Resting Heart Rate, the calculator switches to the Karvonen formula. This is generally considered more accurate for individuals with varying fitness levels. It calculates your Heart Rate Reserve (Max HR – Resting HR) and applies the intensity percentage to that reserve, then adds the resting rate back in.