HRV Biofeedback requires to breathe at low frequencies (deep breathing), which stimulates parasympathetic activity. Experimental studies have found the highest amplitudes in instantaneous heart rate oscillations when breathing at approximately 0.1 Hz. This means 6 breaths per minute and is the default in the app
However, the frequency at which amplitude is maximal for a person can be slightly different. This is what is called the resonant frequency and can vary by up to 2 breath/minute between people
Your resonant frequency can be established with a protocol that consists of breathing at different frequencies for a few minutes until the frequency that elicits the maximal amplitude is found
In our Pro platform, you can analyze minute by minute data collected while breathing at different frequencies, as well as the power spectrum, as shown below
For each breathing frequency, we report the low frequency power as well as SDNN, a feature that captures the overall oscillations in instantaneous heart rate, so that you can see differences between various rates for your tests and your clients'
The resonant frequency as determined by the app, is also highlighted in red:
Finally, the power spectrum will report the main frequency of the session: