However, hi-frequency HRV is consistently reduced by increases in respiration rate and decreases in depth of breathing. Respiration rate typically increases with the types of stressors you seem to describe (much more specficity is needed to know better what you did and how you measured HRV. Just respect Nyquist, (fsam>2*fmax) but don't go to more than 4*fmax, as doing that will not improve your spectral estimation and will demand an artificially higher model order (and consequently longer processing time). Also beware that AR does not require a sampling frequency which is too high. In my experience an order of around p=16 should produce good results. Fortunately there are several good techniques for finding the 'optimum order' of the AR model. Also AR can only 'see' a maximum of p/2 spectral peaks for a model order p. The 'difficulties' associated with AR are that (I) it requires the choice of a 'model order' p and (ii) it is slower than FFT for the same data set. For the same data length AR has a better spectral resolution than FFT, especially for short data segments. AR assumes that future values can be predicted from a linear combination of previous values (that is, that there will be no discontinuities on the signal and a certain number of derivatives). Their results depend on how close the assumptions built in the 2 different techniques hold. But if you run a within-subject comparison, any significant change in respiration parameters (rate, depth) would affect all HRV indexes.įFT and AR are both estimates of the spectrum. In some studies there has been no clear association between resting breathing frequency and HRV frequency domain indexes in healthy volunteers when they did between-subject comparisons ( ). Pay attention that this effect is more obvious when you look within-subject not between-subject. If breathing frequency concentrate in LF band, you will see a rise in LF power. Therefore, if breathing frequency concentrate at HF you will see a peak in HF band. Effects on frequency domain depend on the breathing frequency BPV and HRV frequency exactly follows the breathing frequency.

The lower breathing frequency the higher RMSSD.

Both breathing frequency and tidal volume affects HRV. These conditions (except baseline) were while subjects breathed through a breathing circuit usually leading to higher tidal volume. SB0,5,10 are various slow breathing techniques. Here NB is uncontrolled breathing and PB is paced breathing at 0.23 Hz (similar to breathing rate at baseline). Look at the attached picture from our study. Respiratory parameters not only affects frequency domain indexes of HRV but also time domain indexes like RMSSD.

Labchart reader mac guide