Relative Timing Of Inspiration And Expiration Affects Respiratory Sinus Arrhythmia

Abstract

1. The effect of a variation in inspiration and expiration times on heart rate variability was studied in 12 healthy subjects (mean age 30+/-6 years; five females). 2. Two 2 min trials of controlled breathing, with either short inspiration followed by long expiration or long inspiration followed by short expiration, were compared. Average expiration/inspiration time ratios were 1.0 and 3.4, respectively. The respiration rate in both trials was approximately 10 cycles/min. 3. In trials with short inspiration followed by long expiration, respiratory sinus arrhythmia (RSA; as measured by mean absolute differences and by the high frequency band) was significantly larger than in trials with long inspiration followed by short expiration. This effect could not be accounted for by differences in respiration rate or respiratory amplitude. The higher RSA during fast/slow respiration is primarily due to a more pronounced phasic heart rate increase during inspiration, indicating that inspiratory vagal blockade is sensitive to the steepness of inspiration. 4. Respiration rate and tidal volume are respiratory variables known to modulate RSA. The results of the present study indicate that RSA can also be modulated by a third respiratory variable, the expiratory/inspiratory time ratio.

Favouring emotional processing in improvisational music therapy through resonance frequency breathing: a single-case experimental study with a healthy client

“…Generally speaking, we know that HRV is higher when exhalations last longer than inhalations (Strauss-Blasche et al, 2000). Furthermore, in a study investigating specifically the effect of the i/e ratio when breathing at 6 breaths/min (Diest et al, 2014), participants reported more relaxation, positive energy, stress reduction, and mindfulness with a low i/e ratio (exhales > inhales), compared to a high i/e ratio (inhales > exhales).…”

In vivo cardiac phase response curve elucidates human respiratory heart rate variability

“…It is well known [23][24][25][45][46][47][48]51,52 that the phase of respiration influences the peripheral autonomic nervous system's outflow to the heart. However, till now it has never been shown when exactly this happens inside the cardiac cycle.…”

“…Description of cardiorespiratory interaction in terms of coupling functions yields a new technique for the quantification of respiratory-related HRV. HRV is one of the central tools of psychophysiology and behavioural medicine 44 , and the respiratory component is a significant part of it [23][24][25][45][46][47][48] , representing mainly the vagal or parasympathetic part of the autonomic nervous system influences. Having introduced the time-continuous phase of the ECG, we obtain a continuous description of the HRV via the instantaneous frequency _ j e ðtÞ, instead of the commonly used discontinuous beat-to-beat description.…”

Initial evaluation of a four‐dimensional computed tomography system, using a programmable motor

“…This is consistent with physiologic observations. Indeed, during free breathing, E/I has been measured at 1.8 (24) . For a t varying between ‐ c and 0, this equation describes a realistic breathing cycle.…”