Respiration rate, or breaths per minute (brpm), is a vital health metric tracked by modern Garmin smartwatches. Unlike traditional methods that require chest straps to measure torso expansion, Garmin utilizes an advanced optical analysis technique derived from Heart Rate Variability (HRV).
Specifically, Garmin relies on the physiological phenomenon known as Respiratory Sinus Arrhythmia (RSA). When you inhale, your heart rate naturally increases slightly; when you exhale, it decreases. By analyzing the beat-to-beat variability (R-R intervals) detected by the optical heart rate sensor, Firstbeat Analytics algorithms can interpret these cyclic patterns to estimate your breathing rate without any additional equipment.
The Science: Respiratory Sinus Arrhythmia (RSA)
The calculation is based on the correlation between cardiac cycles and respiratory cycles:
Inhalation: Vagus nerve activity is suppressed, causing the Heart Rate (HR) to accelerate and the R-R interval (time between beats) to shorten.
Exhalation: Vagus nerve activity resumes, causing the HR to decelerate and the R-R interval to lengthen.
Garmin's algorithm filters out "noise" (like movement) and identifies the frequency of these high-low heart rate oscillations to produce a breaths-per-minute value.
Respiration Rate Verification Calculator
Use this tool to manually verify the accuracy of your Garmin's respiration data. Since Garmin uses HRV estimation, it can sometimes differ from manual counts, especially during irregular heart rhythms or low HRV periods.
Garmin Respiration Accuracy Checker
Compare manual observations against optical sensor data
Actual Respiration Rate
— brpm
Based on your manual count.
Sensor Accuracy Deviation
–%
Difference between device and reality.
How Garmin Derived This:
Based on your actual rate of 0 brpm, your Garmin optical sensor should detect approximately 0 Heart Rate Acceleration/Deceleration cycles (RSA events) every minute.
Factors Affecting Garmin's Accuracy
Since Garmin calculates respiration rate mathematically via HRV rather than measuring physical airflow, several factors can impact the precision:
1. Low Heart Rate Variability (HRV)
As stress increases, HRV decreases, making the rhythmic changes in heart rate (RSA) harder to detect. If the "signal" of your breath is overwhelmed by the "noise" of a steady, stressed heart beat, the algorithm may struggle.
2. Movement Artifacts
The optical sensor relies on light penetration. Running or high-intensity interval training (HIIT) introduces motion noise that can obscure the subtle R-R interval shifts used to calculate respiration.
3. Cardiac Arrhythmias
Conditions like Atrial Fibrillation (AFib) cause irregular heartbeats that disrupt the predictable pattern of RSA. In these cases, Garmin's respiration data is often unreliable because the heart rate changes are driven by electrical irregularity, not breathing.
Note: Garmin typically provides the most accurate respiration data during sleep or rest, where movement is minimal and RSA is most pronounced due to parasympathetic nervous system dominance.
function calculateRespiration() {
// Get input values
var manualBreaths = parseFloat(document.getElementById("manualBreaths").value);
var observationTime = parseFloat(document.getElementById("observationTime").value);
var garminReading = parseFloat(document.getElementById("garminReading").value);
// Validation
if (isNaN(manualBreaths) || manualBreaths <= 0) {
alert("Please enter a valid number of counted breaths.");
return;
}
if (isNaN(observationTime) || observationTime 0) {
var diff = Math.abs(garminReading – calculatedBRPM);
var deviation = (diff / calculatedBRPM) * 100;
deviation = Math.round(deviation * 10) / 10;
document.getElementById("devResult").innerHTML = deviation + "%";
var devText = "";
if (deviation < 10) {
devText = "Excellent accuracy. The RSA (HRV) detection is working well.";
document.getElementById("devResult").style.color = "#27ae60";
} else if (deviation < 20) {
devText = "Moderate accuracy. Typical for activity or mild stress.";
document.getElementById("devResult").style.color = "#f39c12";
} else {
devText = "High deviation. Low HRV, movement, or sensor fit may be interfering.";
document.getElementById("devResult").style.color = "#c0392b";
}
document.getElementById("devText").innerHTML = devText;
} else {
document.getElementById("devResult").innerHTML = "–";
document.getElementById("devText").innerHTML = "Enter Garmin value to see deviation.";
}
// Show results
document.getElementById("results-area").style.display = "block";
}