Supplementary Material for: A Randomized Controlled Crossover Trial to Determine the Effects of Three Nostril Regulated Breathing Practices on Attention and Mood

Background: Previous studies on nostril regulated breathing have contrasting findings attributed to lack of controls or not taking into account baseline nostril patency. This randomized crossover study on the effects of three nostril regulated yoga breathing practices and two controls on mood states and attention attempted to address these issues.
Materials and methods: Forty-five participants between 20 and 45 years (group mean age ± SD; 24.3±3.8 years; M;F 23:22) were assessed in five sessions in random order on five separate days. Nostril patency recorded pre-interventions in 225 sessions showed right nostril dominant at rest (RNDR) in 136 and left nostril dominant at rest (LNDR) in 89 sessions. The sessions were: (i) SAV or right uninostril breathing, (ii) CAV or left unnostril breathing, (iii) (AV or alternate nostril yoga breathing, (iv) breath awareness (BAW), and (v) quiet seated rest (QS). The practices were for 15 min each. Nostril patency was recorded pre, Brief mood introspection scale (BMIS), Global Vigor and Affect Scale (GVA) and Six letter cancellation test (SLCT) were recorded pre and post each session. Data analysis used general linear mixed model analysis, with fixed effects of states (pre and post), sessions and baseline nostril dominance (right or left).
Results: A significant interaction of sessions, states and nostril dominance at baseline was observed for total global affect (GA) (F9,396.194=2.871, p=0.003) which increased after SAV, CAV, AV and QS in participants right nostril dominant at rest (NDR) (padj<0.05 in all cases). A significant main effect of states was observed followed by significant post-hoc pair wise comparison in right NDR for (i) pleasant mood after SAV, CAV, AV and QS, (ii) positive mood after SAV and AV, and (iii) global vigor after SAV, CAV, AV and QS, and (iv) a decrease in negative mood after CAV and AV. While the volunteers who had left NDR showed a significant increase in (i) PU after CAV, AV, and QR, (ii) PT after CAV, and (iii) GV after CAV and QS.
Conclusion: Nostril dominance pre intervention appears to influence the effects of nostril regulated yoga breathing practices.