Tuesday, August 25, 2020

HRV biofeedback

 Meditation and bio-feedback.

HRV - heart rate variability

On an ECG - electrocardiogram - you get the letters P Q R S T.
The time between two R, noted as R-R is HRV.

Initially researched by HearthMath institute it has been now accepted and implmented by many.

During relaxation the parasympathetic nervous system dominates, heart bpm drops and HRV increases
During stress the sympathetic nervous system dominates, heart bpm increases and HRV decreases

If you are chronically stressed or injured etc the body will stay in a sympathetic mode to sustain recovery even while resting. This is consuming for the body and you should not do any stressful activities like training, tough decisions etc. that like overcome the body's ability to compensate and it will trow you out of balance and in a bad state of health.
Hence the need to read your morning HRV so you know how your body is doing and how you continue your day.

Sensors:

- HearthMath Inner Balance sensor: many reviews on amazon say the sensor's quality is not reflected by its price which is around 160$ + shipping
- Polar H7/H9 or H10 - H10 being the best for accuracy - most easy to find and buy locally ~ 100$
- CorSense from the maker of the app https://elitehrv.com/ - 165$ - but expensive outside of the US ( around 200$ in europe with added vat) - the most convenient one to use

Polar H7 and H9 vs Poalr H10

You can see in the above image, the H10 has the same metal rounded electrode that is crimped to the connector, but also another rectangular metal band behind it that acts as a shield connected to ground to prevent exterior interference.  

Note: i bought an spare chest strap from aliexpress that it is rated as a replacement for the H10 but it only has the main electrode and no shielding - so it is an equivalent to the H7/H9 soft strap.

“The extra interference-preventing electrodes on the strap make it extremely sensitive to your heart’s electrical signals, providing maximum precision for heart rate readings and eliminating interference.”