Target Heart Rate Calculator (On Beta Blockers)
Beta blockers are medications that reduce heart rate and blood pressure. When exercising, it's important to understand your target heart rate zone, which will be lower when you are taking beta blockers. This calculator helps you estimate your target heart rate zone while accounting for the effects of beta blockers.
Age (years):
Estimated Maximum Heart Rate (bpm):
Typically estimated as 220 minus your age. If you have a physician-determined MHR, use that value.
Beta Blocker Reduction Factor (0-100%):
This is the percentage by which your beta blocker typically reduces your heart rate. Consult your doctor if unsure.
Exercise Intensity Level (%):
50% (Light Intensity)
60% (Light to Moderate Intensity)
70% (Moderate Intensity)
80% (Vigorous Intensity)
85% (Very Vigorous Intensity)
Calculate Target Heart Rate
.calculator-container {
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max-width: 500px;
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.calculator-container button:hover {
background-color: #0056b3;
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#result {
margin-top: 20px;
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border-radius: 5px;
text-align: center;
font-size: 1.1em;
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function calculateTargetHeartRate() {
var age = parseFloat(document.getElementById("age").value);
var maxHeartRateEstimate = parseFloat(document.getElementById("maxHeartRateEstimate").value);
var betaBlockerFactor = parseFloat(document.getElementById("betaBlockerFactor").value);
var intensityLevel = parseFloat(document.getElementById("intensityLevel").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(age) || age <= 0) {
resultDiv.innerHTML = "Please enter a valid age.";
return;
}
if (isNaN(maxHeartRateEstimate) || maxHeartRateEstimate <= 0) {
resultDiv.innerHTML = "Please enter a valid estimated maximum heart rate.";
return;
}
if (isNaN(betaBlockerFactor) || betaBlockerFactor 100) {
resultDiv.innerHTML = "Please enter a valid beta blocker reduction factor between 0 and 100.";
return;
}
if (isNaN(intensityLevel) || intensityLevel 100) {
resultDiv.innerHTML = "Please select a valid exercise intensity level.";
return;
}
// Calculate heart rate reduced by beta blockers
var betaReducedMHR = maxHeartRateEstimate * (1 – (betaBlockerFactor / 100));
// Calculate target heart rate zone
var lowerBound = betaReducedMHR * (intensityLevel / 100);
var upperBound = betaReducedMHR * ((intensityLevel + 10) / 100); // Using a typical 10% range for the upper bound
// Ensure lower bound isn't negative
if (lowerBound < 0) {
lowerBound = 0;
}
// Ensure upper bound isn't negative or lower than lower bound
if (upperBound < 0 || upperBound < lowerBound) {
upperBound = lowerBound;
}
resultDiv.innerHTML = "Your estimated target heart rate zone on beta blockers is:
" +
Math.round(lowerBound) + " – " + Math.round(upperBound) + " bpm ";
}