Comparison of four yogic breathing techniques regarding their impact on heart-rate variability and breathing frequency

Abstract

Background: The manner of breathing affects the autonomic nervous system (ANS) and corresponding processes in the body. Most studies focus on techniques prolonging breathing. Nevertheless, there are also techniques aimed at accelerating or changing other aspects of the breath. The variety of concepts suggests that different breathing techniques could have different effects on the ANS. This study intended to investigate differential effects of four yogic breathing techniques on heart-rate variability: (1) Ujjayi—relaxation through slowing down the breath; (2) Paced Breathing—enhancement of concentration by following a precise protocol of slowdown breathing; (3) Kapalabhati—raising wakefulness by mild hyperventilation; and (4) Alternate Nostril Breathing—balancing the autonomic nervous system by alternating breath between the nostrils. We hypothesized that there would be (1) differences in the impact on baseline measures after the training weeks, (2) differences between baseline and practice, (3) higher impact with longer performance of the breathing technique, and (4) differences between techniques. Methods: This study was conducted with 36 participants who learned each technique in group sessions and practiced them daily for two weeks of an eight-week program. After practicing each technique, participants performed the breathing technique while HRV, breathing frequency and other psychological variables were recorded; rMSSD was calculated for to interpret the HRV. Results: We found significant differences between calming and accelerating breathing techniques on HRV and breathing frequency, and different effects of the four breathing techniques compared to their baseline and over practice time. Conclusions: Because breathing is such an easily accessible tool for regulation, it seems important to see which breathing technique helps people regulate quickly and effectively in everyday life.