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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