Breath Phase Durations, Affect, and Attention: A Pilot Randomized Crossover Trial

Objectives: Previously, yoga volitional breathing with low inspiration to expiration ratios (i/e) (as in bhramari pranayama ) improved cognition and reduced state anxiety. This study compared the effects of low, high and equal i/e ratio breathing on affect and attention. Material and Methods: Affect, vigor and attention were assessed in forty healthy participants (group mean age± SD; 22.58±3.83; M:F= 2.33:1) while breathing with three different i/e regulated by a visual metronome on separate days viz., (i) low i/e (28:72), (ii) equal i/e (50:50), (iii) high i/e (72:28) compared to control, without conscious breath modification. Assessments were: (i) brief mood introspection scale (BMIS), (ii) global vigor and affect scale (GVAS), (iii) Spielberger's state trait anxiety inventory-state (STAI-S) and a six letter cancellation test to assess sustained attention. Data were analyzed with repeated measures analysis of variance with Bonferroni adjusted post-hoc tests. Results: Pleasant feelings increased after low and equal i/e. Low i/e also increased positive feelings whereas equal i/e decreased scores in the cancellation test for sustained attention. All three breathing practices and the control session decreased state anxiety and increased vigor. High i/e breathing alone did not decrease negative feelings. For all the breath ratios the breath frequency cue was set at twelve breaths per minute. Conclusion: In summary, varying breath phase ratios influenced positive and pleasant feelings but did not influence state anxiety or vigor. Understanding the mechanisms underlying the findings would be improved with concurrent physiological assessments.