A Comparison of Practice Guidelines for Yoga Breathing from the Traditional Texts and PubMed-Indexed Research.

Volitional yoga breathing techniques influence several physiological functions depending on the changes made in depth of breathing, relative duration of exhalation to inhalation, and breath frequency. The practice guidelines for three routinely practiced and researched yoga breathing practices (bhastrika pranayama [bellows breath], bhramari pranayama [bee breath], and kapalabhati pranayama [breath of fire]) were compared between the traditional written texts (i.e., Hatha Yoga Pradipika, Gheranda Samhita) and published research indexed in PubMed (a total of 73 studies; 25 on bhastrika pranayama, 17 on bhramari pranayama, and 31 on kapalabhati pranayama). We compared the specifications for posture, time of day, location, and duration of practice; frequency, depth, and holding (kumbhaka) of the breath; speed and/or force and right or left nostril use for inhalation and exhalation; duration of inhalation relative to exhalation; thoracic or diaphragmatic breathing (or comparable terms in the traditional texts); mental state; physiological locks (bandhas) ; and hand gestures (mudras). Differences between the practice guidelines in the traditional texts and published research with respect to the depth of b reathing (bhastrika pranayama), relative breath phase duration (bhramari pranayama), and breath frequency (kapalabhati pranayama) are presented despite the findings being restricted to published studies from a single bibliographic database. Differences in the way yoga breathing is practiced could influence the physiological effects obtained, and differences between methods reported in published studies could make it difficult to summarize the effects of yoga breathing practice across studies.