Effect of uninostril yoga breathing on brain hemodynamics: A functional near-infrared spectroscopy study

OBJECTIVES: To measure the effect of the right and left nostril yoga breathing on frontal hemodynamic responses in 32 right handed healthy male subjects within the age range of 18–35 years (23.75 ± 4.14 years). MATERIALS AND METHODS: Each subject practiced right nostril yoga breathing (RNYB), left nostril yoga breathing (LNYB) or breath awareness (BA) (as control) for 10 min at the same time of the day for three consecutive days, respectively. The sequence of intervention was assigned randomly. The frontal hemodynamic response in terms of changes in the oxygenated hemoglobin (oxyHb), deoxygenated hemoglobin (deoxyHb), and total hemoglobin (totalHb or blood volume) concentration was tapped for 5 min before (pre) and 10 min during the breathing practices using a 16 channel functional near-infrared system (FNIR100-ACK-W, BIOPAC Systems, Inc., U.S.A.). Average of the eight channels on each side (right and left frontals) was obtained for the two sessions (pre and during). Data was analyzed using SPSS version 10.0 through paired and independent samples t-test. RESULTS: Within group comparison showed that during RNYB, oxyHb levels increased significantly in the left prefrontal cortex (PFC) as compared to the baseline (P = 0.026). LNYB showed a trend towards significance for reduction in oxyHb in the right hemisphere (P = 0.057). Whereas BA caused significant reduction in deoxyHb (P = 0.023) in the left hemisphere. Between groups comparison revealed that oxyHb and blood volume in the left PFC increased significantly during RNYB as compared to BA (oxyHb: P =0.012; TotalHb: P =0.017) and LNYB (oxyHb: P =0.024; totalHb: P =0.034). CONCLUSION: RNYB increased oxygenation and blood volume in the left PFC as compared to BA and LNYB. This supports the relationship between nasal cycle and ultradian rhythm of cerebral dominance and suggests a possible application of uninostril yoga breathing in the management of psychopathological states which show lateralized cerebral dysfunctions.