function calculateBreathingRate() {
var peaksInput = document.getElementById('br_peaks');
var durationInput = document.getElementById('br_duration');
var unitInput = document.getElementById('br_unit');
var resultBox = document.getElementById('br_result');
var bpmDisplay = document.getElementById('br_bpm_display');
var interpretationSpan = document.getElementById('br_interpretation');
var peaks = parseFloat(peaksInput.value);
var duration = parseFloat(durationInput.value);
var unit = unitInput.value;
// Input Validation
if (isNaN(peaks) || peaks <= 0) {
alert("Please enter a valid number of breaths (peaks).");
return;
}
if (isNaN(duration) || duration <= 0) {
alert("Please enter a valid time duration.");
return;
}
// Logic: Convert to Minutes based on unit
var timeInMinutes = 0;
if (unit === 'seconds') {
timeInMinutes = duration / 60;
} else {
timeInMinutes = duration;
}
// Calculate BPM
var bpm = peaks / timeInMinutes;
// Round to 1 decimal place
bpm = Math.round(bpm * 10) / 10;
// Determine clinical status (Adult standards)
var statusText = "";
var statusClass = "";
if (bpm = 12 && bpm <= 20) {
statusText = "Normal Range";
statusClass = "status-normal";
} else {
statusText = "High (Tachypnea)";
statusClass = "status-high";
}
// Update Output
bpmDisplay.innerHTML = bpm + " BPM";
interpretationSpan.innerHTML = "" + statusText + "";
resultBox.style.display = "block";
}
How to Calculate Breathing Rate from a Graph
Calculating breathing rate (respiratory rate) from a graph—typically a spirometry trace or a respiratory waveform—is a fundamental skill in physiology and healthcare. These graphs visualize the volume of air moving in and out of the lungs over time.
1. Understanding the Axes
Before calculating, you must understand what the graph represents:
Y-Axis (Vertical): Represents the Volume of air (usually in Liters or Milliliters). Upward movement typically indicates inspiration (breathing in), and downward movement indicates expiration (breathing out).
X-Axis (Horizontal): Represents Time (usually in seconds).
2. Identifying a Breath Cycle
To calculate the rate, you must first count the number of breath cycles within a specific timeframe. A single breath cycle consists of one inhalation and one exhalation.
The Peak Method: Count the number of highest points (peaks) on the wave. Each peak represents the end of an inhalation.
The Trough Method: Count the lowest points (troughs). Each trough represents the end of an exhalation.
Ensure you are consistent. Do not count both peaks and troughs; choose one feature to represent one full breath.
3. The Calculation Formula
Once you have the number of breaths (peaks) and the time duration of the graph section you analyzed, use the following formula to determine Breaths Per Minute (BPM):
Formula (if time is in seconds):
BPM = (Number of Breaths / Time in Seconds) × 60
Example:
If you count 5 peaks (breaths) over a period of 15 seconds on the X-axis:
5 / 15 = 0.333 breaths per second
0.333 × 60 = 20 BPM
4. Interpreting the Results
For a resting adult, the normal respiratory rate differs from that of children or infants. Understanding these ranges helps in clinical assessment.
Normal (Eupnea): 12–20 breaths per minute.
Low (Bradypnea): Below 12 breaths per minute. Can be caused by sedation, sleep, or head injury.
High (Tachypnea): Above 20 breaths per minute. Can be caused by exertion, anxiety, fever, or respiratory distress.
Use the calculator above to quickly convert your counts from a graph trace into a clinical Breaths Per Minute value.