Supplementary Material for: Volitional Yoga Breathing Influences Attention and Anxiety: An Exploratory Randomized Crossover Study

<b><i>Background:</i></b> Previous studies assessed yoga breathing practices individually. This exploratory, randomized crossover study assessed attention and anxiety following four yoga breathing practices, breath awareness, and quiet seated rest. <b><i>Materials and Methods:</i></b> Thirty-eight male volunteers between 20 and 37 years (group mean age ± SD; 24.08 ± 4.01 years) were assessed in six sessions in random order (www.randomizer.org) on separate days. The sessions were: (i) alternate nostril yoga breathing, (ii) bellows yoga breathing, (iii) bumblebee yoga breathing, (iv) high-frequency yoga breathing, (v) breath awareness, and (vi) quiet seated rest. The sessions were for 18 min each. Six letter cancellation test (SLCT) and Spielberger’s State Trait Anxiety Inventory-state (STAI-s) were administered pre and post each session. Data analysis used general linear mixed model analysis, with fixed effect of states (pre and post) and sessions. <b><i>Results:</i></b> A significant main effect of states was observed on total attempted (<i>F</i>_1,407 = 5.374, <i>p</i> = 0.021) and net attempted scores (<i>F</i>_1,407 = 6.178, <i>p</i> = 0.013) of the SLCT, with a significant increase in scores following high-frequency yoga breathing (<i>p</i>_<i>adj</i> = 0.031 for total attempted scores; <i>p</i>_<i>adj</i> = 0.029 for net attempted scores). Also, a significant main effect of states on STAI-s scores was observed (<i>F</i>_1,407 = 33.979, <i>p</i> &lt; 0.001), with a significant decrease in scores following alternate nostril yoga breathing (<i>p</i>_<i>adj</i> = 0.001), bellows yoga breathing (<i>p</i>_<i>adj</i> = 0.008), bumblebee yoga breathing (<i>p</i>_<i>adj</i> = 0.002), and high-frequency yoga breathing (<i>p</i>_<i>adj</i> = 0.042) compared to the corresponding pre state. There was a significant main effect of sessions (<i>F</i>_5,407 = 3.043, <i>p</i> = 0.010) on STAI-s scores, with scores post alternate nostril yoga breathing significantly lower than post breath awareness (<i>p</i>_<i>adj</i> = 0.037). <b><i>Conclusion:</i></b> Following high-frequency yoga breathing sustained attention was better than before while state anxiety decreased in post-pre comparisons of alternate nostril yoga breathing, bellows yoga breathing, bumblebee yoga breathing, and high-frequency yoga breathing. The differences between breathing practices may be due to differences in degree of volitional regulation of breathing and in the breath patterns modified volitionally. The generalizability of the findings was limited by including an all male, yoga experienced sample. Future research should include participants of both genders and could include different levels of yoga experience, with assessments including objective measures of attention and anxiety.