Differential effects of uninostril and alternate nostril pranayamas on cardiovascular parameters and reaction time

BACKGROUND: Recent studies have reported the differential physiological and psychological effects of yogic uninostril breathing (UNB) and alternate nostril breathing (ANB) techniques. This study aims to determine differential effects of these techniques on reaction time (RT), heart rate (HR), and blood pressure (BP). MATERIALS AND METHODS: Twenty yoga-trained subjects came to the lab on six different days and RT, HR, and BP were recorded randomly before and after nine rounds of right UNB (surya nadi [SN]), left UNB (chandra nadi [CN]), right initiated ANB (surya bhedana [SB]), left initiated ANB (chandra bhedana [CB]), nadi shuddhi (NS), and normal breathing (NB). RESULTS: Overall comparison of ∆ % changes showed statistically significant differences between groups for all parameters. There was an overall reduction in HR- and BP-based parameters following CB, CN, and NS with concurrent increases following SB and SN. The differential effects of right nostril initiated (SB and SN) and left nostril initiated (CB, CN, and NS) UNB and ANB techniques were clearly evidenced. Changes following NB were insignificant in all respects. The overall comparison of ∆ % changes for RT showed statistically significant differences between groups that were significantly lowered following both SB and SN. DISCUSSION AND CONCLUSION: Our study provides evidence of sympathomimetic effects of right nostril initiated pranayamas with sympatholytic/parasympathomimetic effect following left nostril initiated pranayamas. We suggest that the main effect of UNB and ANB techniques is determined by the nostril used for inspiration rather than that used for expiration. We conclude that right and left yogic UNB and ANB techniques have differential physiological effects that are in tune with the traditional swara yoga concept that air flow through right nostril (SN and pingala swara) is activatory in nature, whereas the flow through left nostril (CN and ida swara) is relaxatory.