Fitbit Resting Heart Rate Calculator
Fitbit devices continuously monitor your heart rate throughout the day and night. To calculate your Resting Heart Rate (RHR), Fitbit typically considers your heart rate readings during periods of inactivity, specifically when you are asleep or very still. The device averages these low-heart-rate readings over a specific period (often 24 hours, but can be influenced by longer sleep periods) to determine your RHR. This provides a baseline measure of your cardiovascular fitness. A lower RHR generally indicates better heart health and efficiency.
function calculateFitbitRHR() {
var sleepHeartRate = parseFloat(document.getElementById("sleepHeartRate").value);
var awakeStillnessHeartRate = parseFloat(document.getElementById("awakeStillnessHeartRate").value);
var measurementPeriodHours = parseFloat(document.getElementById("measurementPeriodHours").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(sleepHeartRate) || isNaN(awakeStillnessHeartRate) || isNaN(measurementPeriodHours) ||
sleepHeartRate <= 0 || awakeStillnessHeartRate <= 0 || measurementPeriodHours <= 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
// Fitbit's algorithm is complex and proprietary.
// This is a simplified model to demonstrate the concept of averaging low heart rate readings.
// It assumes sleep heart rate is a significant contributor and weighs awake stillness less.
var weightedSleepRate = sleepHeartRate * 0.7; // Sleep is weighted higher
var weightedAwakeStillnessRate = awakeStillnessHeartRate * 0.3; // Awake stillness is weighted lower
var calculatedRHR = weightedSleepRate + weightedAwakeStillnessRate;
// Another simplified approach is to just average the lowest readings.
// For demonstration, we'll use a blend or primarily focus on sleep if provided.
// Fitbit also filters out high readings during sleep if any occur.
// This calculation is a conceptual approximation.
resultDiv.innerHTML =
"
Estimated Fitbit Resting Heart Rate: " + calculatedRHR.toFixed(1) + " bpm" +
"
Note: This is a simplified model. Fitbit's actual algorithm is proprietary and uses extensive data filtering and averaging over time.";
}
#fitbit-rhr-calculator {
font-family: sans-serif;
max-width: 600px;
margin: 20px auto;
padding: 20px;
border: 1px solid #ccc;
border-radius: 8px;
background-color: #f9f9f9;
}
#fitbit-rhr-calculator h2 {
text-align: center;
color: #333;
margin-bottom: 20px;
}
.calculator-inputs {
display: flex;
flex-direction: column;
gap: 15px;
}
.input-row {
display: flex;
align-items: center;
justify-content: space-between;
margin-bottom: 10px;
}
.input-row label {
flex-basis: 60%;
font-weight: bold;
color: #555;
}
.input-row input {
flex-basis: 35%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
box-sizing: border-box;
}
#fitbit-rhr-calculator button {
padding: 12px 20px;
background-color: #007bff;
color: white;
border: none;
border-radius: 5px;
cursor: pointer;
font-size: 16px;
transition: background-color 0.3s ease;
margin-top: 15px;
}
#fitbit-rhr-calculator button:hover {
background-color: #0056b3;
}
#result {
margin-top: 25px;
padding: 15px;
border-top: 1px solid #eee;
text-align: center;
font-size: 1.1em;
}
#result p {
margin: 5px 0;
}
#result small {
color: #888;
font-size: 0.9em;
}