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

Abstract

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. 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. 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. 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.