Inhalation/Exhalation Ratio Modulates the Effect of Slow Breathing on Heart Rate Variability and Relaxation

Abstract

Slow breathing is widely applied to improve symptoms of hyperarousal, but it is unknown whether its beneficial effects relate to the reduction in respiration rate per se, or, to a lower inhalation/exhalation (i/e) ratio. The present study examined the effects of four ventilatory patterns on heart rate variability and self-reported dimensions of relaxation. Thirty participants were instructed to breathe at 6 or 12 breaths/min, and with an i/e ratio of 0.42 or 2.33. Participants reported increased relaxation, stress reduction, mindfulness and positive energy when breathing with the low compared to the high i/e ratio. A lower compared to a higher respiration rate was associated only with an increased score on positive energy. A low i/e ratio was also associated with more power in the high frequency component of heart rate variability, but only for the slow breathing pattern. Our results show that i/e ratio is an important modulator for the autonomic and subjective effects of instructed ventilatory patterns.

The effect of continuous positive airway pressure on heart rate variability during the night in patients with chronic heart failure and central sleep apnoea

“…Our findings of a significant decrease in SDNN, RMSSD, LF and HF with CPAP therapy in patients with CSA may be attributed to the normalized breathing pattern during the night in those patients, since these parameters are strongly dependent on respiration frequency and depth . In concordance with that explanation is the presence of a significant strong correlation between the decrease in AHI and in lnHF (influenced strongly by breathing pattern) with the application of CPAP. Similar results with a decrease in HRV parameters after CPAP application were found by Kufoy et al.…”

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 the present study, the i/e ratio was set to 40/60, meaning that inhalation lasted 3.7 s and exhalation 5.5 s.…”

The effects of breathing at a frequency of 0.1 Hz on affective state, the cardiovascular system, and adequacy of ventilation

“…Regarding adequacy of ventilation, we expected that paced breathing will decrease PetCO 2 . On the basis of previous studies, we did not expect that breathing at 0.1 Hz would affect mean heart rate (Cappo & Holmes, ; McCaul et al, ; van Diest et al, ). In line with the well‐established effects of breathing frequency on RSA, we expected increased RSA during breathing at 0.1 Hz.…”

“…Cappo and Holmes () measured the effects of breathing at 0.1 Hz before the eliciting of negative emotions and reported null findings. Van Diest et al () reported that participants had lower affective arousal after breathing at 0.1 Hz in comparison to 0.2 Hz. Recently, Steffen, Austin, DeBarros, and Brown () reported no effect on anxious arousal but increased positive mood.…”