Heart Rate Variation on Android

Question

How can I get the Heart Rate Variability using the Heart Sensor on Android?

I managed to code an activity to measure the heart rate, but it seems that there is no way to do so for HRV. Any help would be greatly appreciated.

What I tried:

SensorManager manager=(SensorManager)getSystemService(Context.SENSOR_SERVICE);
        Sensor heart=manager.getDefaultSensor(Sensor.TYPE_HEART_RATE);
        manager.registerListener(new SensorEventListener() {
            @Override
            public void onSensorChanged(SensorEvent event) {

            }

            @Override
            public void onAccuracyChanged(Sensor sensor, int accuracy) {
                
            }
        },heart,SensorManager.SENSOR_DELAY_FASTEST);

The above code measures Heart Rate and not Heart Rate Variability.

Definition of Heart Rate Variability: HRV is the physiological phenomenon of the variation in the time interval between consecutive heartbeats in milliseconds.

I'm wondering if it is achievable knowing that I have the heart rate sensor on my Android device.