hrv-time-domain-analysis

Computes time domain metrics of heart rate variability based on a series of RR intervals.

Currently supported metrics:

RMSSD (root mean square of successive interval differences)
SDNN (standard deviation of successive rr intervals)
PNN50 (percentage of successive interval differences larger than 50ms)

Scientific accuracy is not guaranteed.

How to use:

Create a new instance and configure it using the available options.

// import
var HRVAnalysis = require('hrv-time-domain-analysis');

// create and configure HRV Analysis instance (default values below)
var hrv = new HRVAnalysis({
  windowSize: 40, // size of moving analysis timeframe in seconds
  rrTimeFormat: 's', // time format of rr intervals: 's' (seconds) or 'ms' (milliseconds)
  rmssdLog: true, // apply natural logarithm to rmssd 
  rmssdFactor: 20 // multiply rmssd value by this factor
});

Upon receiving rr intervals from a heart rate monitoring device, add them to the analysis window.

hrv.addRRs(rrs) // where rrs is an array of (usually 1 or 2) rr intervals

Listen for analysis results. Once there is enough value (depends on size of analysis window) a 'data' event is emitted including the available hrv time domain metrics.

hrv.on('data', ({ rmssd, sdnn, pnn50 }) => {
  // do things with the metrics, e.g. display in graph, create recording etc.
})

That's it, enjoy!

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