Leo is a digital companion who stands by our side while we bring our dreams to life.
Every evening, Leo guides us through a simple two-minute slow breathing exercise. This is assumed to enable REM sleep - the dreaming phase of our sleep - which is essential for vitality and creativity purposes.
We make sure we breathe gently and softly and breathe in as the ball becomes bigger and breathe out as the ball fades away.
We know in real-time how well we are doing by looking at the HRV score.
How can we get our HRV score?
In order to know our HRV score, we need to apply our finger on the backfacing camera of our smartphone.
Which finger should we apply on the camera?
We look at the back of our phone in order to know which finger to apply.
If the camera is located on the left of the flash, we apply our left index finger.
Otherwise, we apply our right index finger.
How can we minimise a potential sensation of heat?
The contact between our finger and the flash may cause us a sensation of heat. If this happens, we must adapt the position of our finger immediately.
The best and safest way to apply our finger is to apply it 100% on the camera however keep a slight distance between our finger and the flash.
How is the score calculated?
When we breathe at our resonance frequency, our heart rate accelerates when we breathe in and decelerates when we breathe out.
The greater the amplitude of this oscillation, the more flexible our autonomic nervous system.
The current version of the score is based on the amplitude of deceleration in heart rate over two consecutive exhalations (IBI trough-to-peak differences to be specific).
This scoring methodology is a first proxy for the coherence of our autonomic nervous system and it will be further improved in the coming weeks and months.
Based on preliminary testing, Leo’s current HRV signal acquisition includes an average error of c.13 ms vs. the reference HRV acquisition mobile application (Camera HRV) whose accuracy has been demonstrated through the following scientific publication: https://www.researchgate.net/publication/315059917_Comparison_of_Heart_Rate_Variability_Recording_With_Smart_Phone_Photoplethysmographic_Polar_H7_Chest_Strap_and_Electrocardiogram_Methods.
Given the currently used scoring methodology, this error has little impact on the overall accuracy of the score.
This being said, Leo is on good track to bring the accuracy of its HRV signal acquisition to a 180Hz level over the next few weeks and months.