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

Effect of Right Nostril Breathing on Cardiorespiratory Parameters and Reaction Time in Young, Healthy Humans: An Interventional Study

Background and Objective

Yogic breathing helps in reduction of stress and strain in the body. Right and left nostril breathings (RNB and LNB, respectively) have different effects on cardiorespiratory parameters. The study was performed to examine the effect of RNB exercise on cardiorespiratory parameters and reaction time in young, healthy human volunteers.

Materials and Methods

In this prospective, interventional study, 110 young healthy volunteers underwent systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse rate (PR), respiratory rate (RR), vital capacity (VC), peak expiratory flow rate (PEFR), and reaction time (RT) examination before and after 2 weeks of performing 45 min of RNB exercise daily.

Results

There was notable increment in SBP (113.39 ± 17.72 vs. 117.74 ± 10.83 mmHg, P = 0.002) and DBP (67.64 ± 10.32 vs. 71.27 ± 8.68 mmHg, P = 0.002). PR increased nonsignificantly (86.44 ± 12.65/min vs. 87.32 ± 13.43/min, P = 0.476). Significant decrease in RR (14.40 ± 2.48/min vs. 12.31 ± 2.23/min, P < 0.0001) was observed. VC (3.57 ± 0.57 vs. 3.82 ± 0.55 L/min, P < 0.0001) and PEFR (441.36 ± 50.22 vs. 468.91 ± 53.66 L/min, P < 0.0001) also increased significantly. Substantial reduction in auditory reaction time (ART) (165.58 ± 32.18 vs. 147.42 ± 23.39 ms, P < 0.0001) and visual reaction time (VRT) (191.04 ± 37.94 vs. 165.86 ± 28.74 ms, P < 0.0001) was seen. After engaging in cardiorespiratory exercise, the maximal heart rate (MHR) remained unchanged (P = 0.929).

Conclusion

RNB results in increase in blood pressure, heart rate, VC, and PEFR and decrease in ART and VRT. Further studies in patients with cardiorespiratory diseases are necessary to understand its clinical utility.

The Effect of Pranayama Applied to Hemodialysis Patients on Fatigue: A Randomized Controlled Trial

The present study was conducted to examine the effects of Pranayama applied to hemodialysis patients on fatigue. The study was completed with 91 patients, including Pranayama (n = 30), Relaxation (n = 30), and Control groups (n = 31). The patients in the Pranayama group applied the interventions 15 to 20 minutes every day, once a day, for a total of 3 months, and the patients in the relaxation practice group applied the interventions 15 to 20 minutes every day, once a day, for a total of 3 months. Before the study commenced, permission was obtained from health care institutions, the ethics committee, and the patients. The data were collected with a Questionnaire, Piper Fatigue Scale (PFS), visual analog scale, and Vital Findings Form. Piper Fatigue Scale consists of 4 subdimensions, the total score obtained from the scale varies between 0 and 10, and as the score increases, the level of fatigue also increases. It was found that the patients in the Pranayama Group had decreased PFS total and subdimension mean scores after the procedure (P < .05); however, no significant changes were detected in the PFS total and subdimension mean scores of the patients in the Relaxation and Control groups (P > .05). Although the decrease in the daily fatigue severity of the patients in the Pranayama group was at a statistically significant level (P < .05), no statistically significant changes were detected in the fatigue severity of the patients in the Relaxation and Control groups (P > .05). It was also found that the blood pressure values of the patients in the Pranayama and Relaxation groups decreased (P < .05). It was found in the present study that Pranayama reduced the fatigue levels of hemodialysis patients. In this respect, it is recommended to teach and apply Pranayama techniques to patients with the support of nurses.

Effects of Nadishodhana and Bhramari Pranayama on heart rate variability, auditory reaction time, and blood pressure: A randomized clinical trial in hypertensive patients

BACKGROUND

Hypertension (HTN) is a chronic elevation of arterial blood pressure (BP) due to environmental and lifestyle factors. The lifelong treatment protocol causes poor adherence to anti-hypertensive drugs. Nadi Shodhana and Bhramari pranayama are the most effective yogic treatment for the management of HTN.

OBJECTIVES

This study was done to assess and compare the immediate effect of Nadi Shodhana and Bhramari Pranayama on HRV and ART in hypertensive individuals. Thus, to understand the effectiveness of specific pranayama on hypertension.

METHODOLOGY

This study is a randomized, comparative study design. The hundred participants were recruited into two groups 1 (n = 50) and 2 (n = 50). The study was conducted on pre-diagnosed patients with HTN, from the inpatient department of SDM Nature Cure Hospital, Shanthivana. Group 1 was asked to practice Nadi Shodhana Pranayama and Group-2 was asked to practice Bhramari Pranayama for 20 min. The patients were assessed for Heart Rate Variability & Auditory Reaction Time before and immediately after the intervention.

RESULTS

Nadi Shodhana Pranayama showed a significant decrease in ART (p = 0.01) and Bhramari Pranayama showed a highly significant decrease in ART (p < 0.00001). Whereas there was no statistically significant difference in both the groups in HRV parameters.

CONCLUSION

The study showed that both Nadi Shodhana and Bhramari Pranayama can be effective in balancing the sympathovagal tone. Thus, Nadi Shodhana and Bhramari Pranayama can be practised for the management of essential hypertension.

The Effect of Specific Techniques of Nasal Breathing [Pranayama] on Intra-Ocular Pressure in Normal Individuals, a Randomized Trial

PURPOSE

Glaucoma is an optic neuropathy where intraocular pressure is the only modifiable risk factor. Yoga is thought to adversely affect intra-ocular pressure (IOP) but we do not know if yogic breathing exercises can influence IOP. With this study, we aimed to determine the effect of specific nasal breathing techniques on intra-ocular pressure in normal individuals.

PATIENTS AND METHODS

One hundred and sixty-four normal subjects were randomly assigned to one of four specific breathing groups - right nostril breathing (RNB), left nostril breathing (LNB), alternate nostril breathing (ANB), normal breathing (NB). The IOP was measured in both eyes at baseline and following the breathing exercise; and the change was analyzed.

RESULTS

Eighty-five women and 79 men participated and there was no significant difference in baseline age or IOP between the groups. In RNB, IOP reduced significantly in both right and left eyes, from 14.3 ± 3.0mmHg to 13.9 ± 2.6mmHg, (p=0.022) and from 14.7 ± 3.2mmHg to 14.2 ± 3mmHg (p=0.016) respectively. In LNB, there was no significant IOP change in the right eye, whereas in the left eye, there was a significant reduction from 14.2 ± 2.7mmHg to 13.3 ± 2.5mmHg (p< 0.0001). There was no significant IOP change in ANB and NB.

CONCLUSION

Specific breathing techniques like right and left nostril breathing, alternate nostril breathing are safe and do not raise IOP in normal subjects. Additionally, right and left nostril breathing techniques have a beneficial effect of lowering IOP.

Effect of alternate nostril breathing on evoked potentials among internet addicts

Increased availability of smartphones and easy access to the internet among adolescents has resulted in Internet Addiction (IA). Effects of IA and Pranayama on evoked potential are available but studies on the comparison of immediate and 6-week effects of alternate nostril breathing on evoked potentials among medicos with internet addiction are not available as per our search in PubMed, hence the study was chosen. In this comparative study 100 male and female medical students aged between 18-25 years, with internet addiction scores ≥ 50 were included as study participants. P300 auditory event-related potential and pattern reversal visual evoked potential (VEP) were recorded before, immediately, and 6 weeks after practicing pranayama. Repeated measure ANOVA shows statistically significant change (P<0.05) in P300 amplitude, P100 latency, N145 latency, and VEP amplitude. The post hoc Bonferroni test shows that P100 latency and N145 latency significantly reduced immediately after 15 minutes of pranayama. P300 amplitude and VEP amplitude significantly increased only after practicing pranayama for 6 weeks. Pranayama has an immediate effect on latency, but it takes 6 weeks of practice to significantly change amplitude.

Slow yoga breathing improves mental load in working memory performance and cardiac activity among yoga practitioners

This study investigated the immediate effect of slow yoga breathing (SYB) at 6 breaths per minute (bpm) simultaneously on working memory performance and heart rate variability (HRV) in yoga practitioners. A total of 40 healthy male volunteers performed a working memory task, ‘n-back’, consisting of three levels of difficulty, 0-back, 1-back, and 2-back, separately, before and after three SYB sessions on different days. The SYB sessions included alternate nostril breathing (ANB), right nostril breathing (RNB), and breath awareness (BAW). Repeated measures analysis of variance showed a significant reduction in reaction time (ms) in 2-back condition immediately after ANB (−8%), RNB (−8%) and BAW (−5%) practices. Similarly, the accuracy was improved in the 0-back condition after RNB (4%), and in the 2-back condition after ANB (6%) and RNB (6%) practices. These results suggest that SYB practice enhances cognitive abilities (8–9%) related to memory load and improves the functioning of cardiac autonomic activity, which is required for the successful completion of mental tasks.Trial registered in the Clinical Trials Registry of India (CTRI/2018/01/011132).

Immediate autonomic changes during right nostril breathing and left nostril breathing in regular yoga practitioners

BACKGROUND

The ancient Indian science of Yoga makes use of voluntary regulation of breathing to make respiration rhythmic and calm the mind. This practice is called pranayama. Nadisuddhi pranayama means "purification of subtle energy paths," inhalation and exhalation are through alternative nostrils for successive respiratory cycles. Surya Anuloma-Viloma pranayama means "heat generating breathing particle" when the respiratory cycle of inhalation and exhalation is completed through the right nostril exclusively. When completed through the left nostril alone, the practice is called "Chandra Anuloma-Viloma pranayama," which means a heat-dissipating or cooling liberating practice. We compared the effect of right nostril breathing (RNA) and left nostril breathing (LNB) pranayama on heart rate variability.

MATERIALS AND METHODS

The study was conducted at the Department of Physiology at an institute of national importance, after obtaining necessary ethical approvals from the Institutional Ethics Committee. Twenty healthy kriya yogi volunteers (mean age: 44 years), who are regular practitioners for the last 10-20 years, were inducted into the study. RNB pranayama starts with closing the right nostril with the thumb of the left hand followed by exhalation through the right nostril and inhaling slowly through the same nostril. This forms one round of RNB pranayama. In contrast, inhalation through the left nostril and exhalation through the right nostril exclusively is called chandrabhedana pranayama (chandrabhedana means moon-piercing breath in Sanskrit) with a similar variation called Chandra Anuloma-Viloma pranayama in which inhalation, as well as exhalation, is performed through the left nostril exclusively. The recording of electrocardiogram (ECG) for heart rate variability (HRV) analysis was taken by heart rate variability (Dinamika HRV-Advanced Heart Rate Variability Test System, Moscow, Russia). The resting and during readings of heart rate variability parameters were compared and post hoc analysis was done using Bonferroni and Holm multiple comparisons for repeated measures.

RESULTS

Time domain parameters: Standard deviation of normal to normal RR intervals (SDNN) and root mean square of successive NN interval differences (RMSSD) were increased at a high level of statistical significance during both pranayama maneuvres. Frequency domain parameters: LF, LF/HF ratio increased significantly. Parasympathetic activity is represented by LF when the respiration rate is lower than 7 breaths per min or during taking a deep breath. Thus, when the subject is in a state of relaxation with slow and even breathing in both RNB-right nostril and Chandra-LNB, the LF values can be very high, indicating an increase in parasympathetic activity rather than an increase in sympathetic regulation.

CONCLUSION

Our study is an acute study, where changes in HRV were seen after 5 min of RNB and LNB. However, statistically, there is not much difference in the immediate effects of the two pranayamas on heart rate variability in regular yoga practitioners.

Evaluation of the Effect of Left Nostril Breathing on Cardiorespiratory Parameters and Reaction Time in Young Healthy Individuals

Background: Pranayama, a yogic breathing practice, produces several physiological responses in healthy individuals. Hypertension is a critical and booming public health challenge all over the world. Yoga is one of the effective methods to reduce blood pressure (BP) and pulse rate (PR).

Objective: To evaluate the effect of left nostril breathing (LNB) exercise on cardiorespiratory parameters and reaction time (RT) in young healthy individuals.

Materials and methods: In this study, 106 young healthy individuals between 18 and 25 years of age were included. The systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse rate (PR), respiratory rate (RR), vital capacity (VC), peak expiratory flow rate (PEFR), and reaction time (RT) of volunteers were recorded at baseline (before exercise) and after two weeks of left nostril breathing exercise performed 45 minutes daily.

Results: There was a significant reduction in SBP (126.64 ± 15.51 mmHg versus 116.29 ± 11.91 mmHg; Cohen’s d (effect size): 0.87; p < 0.0001)), DBP (76.57 ± 14.87 mmHg versus 71.07 ± 11.39 mmHg; Cohen’s d: 0.48; p < 0.0001), PR (85.32 ± 15.44/minute versus 81.77 ± 13.02/minute; Cohen’s d: 0.27; p < 0.0001), and RR (14.26 ± 2.15/minute to 13.17 ± 2.03/minute; Cohen’s d: 0.54; p < 0.0001). A significant increase was observed in VC (3.42 ± 0.62 versus 3.67 ± 0.65; Cohen’s d: 0.39; p < 0.0001) and PEFR (467.81 ± 46.66 versus 498.29 ± 51.50; Cohen’s d: 0.59; p < 0.0001). There was a significant decrement in auditory reaction time (ART) (164.36 ± 27.20 ms versus 143.84 ± 20.32 ms; Cohen’s d: 0.85; p < 0.0001) and visual reaction time (VRT) (190.25 ± 31.48 ms versus 163.75 ± 21.72 ms; Cohen’s d: 0.98; p < 0.0001). There was no significant change in maximum heart rate (MHR) after cardiorespiratory activity (CRA) (p > 0.434).

Conclusion: Left nostril breathing is associated with a decrease in cardiovascular parameters and an increase in VC and PEFR. This technique may be useful for putting up a fight against the stress and strain of daily life. This simple exercise may also be a beneficial adjuvant to pharmacological therapy in hypertensive patients.

Effect of slow breathing on autonomic tone & baroreflex sensitivity in yoga practitioners

Background & objectives:

Slow breathing increases parasympathetic activity and baroreflex sensitivity (BRS) in healthy individuals, also similarly observed in yoga practitioners. Pranayama which is an important component of yoga when practiced at a slow pace was at a respiratory frequency of around 0.1 Hz (6 breaths/min). Therefore, it was hypothesized that yoga practitioners might have adapted to slow breathing. This study was aimed to decipher the role of yoga on cardiovascular variability during slow breathing (0.1 Hz) in yoga practitioners.

Methods:

A cross-sectional study was undertaken in naïve-to-yoga individuals (n=40) and yoga practitioners (n=40) with an average age of 31.08 ± 7.31 and 29.93 ± 7.57 yr, respectively. The analysis of heart rate variability, blood pressure variability (BPV) and BRS during spontaneous and slow breathing was compared between the two groups.

Results:

During slow breathing, the heart rate (P<0.01) was lower, respiratory rate interval (P<0.05) and pNN50 per cent (P=0.01) were higher, mean systolic BP (SBP) (P<0.05) and SDSD (Standard deviation of successive beat to beat systolic blood pressure differences) (P<0.01) of SBP variability were lower with sequence BRS (P<0.001) and α low frequency (P<0.01) and α high frequency (P<0.001) of spectral BRS were higher in yoga practitioners.

Interpretation & conclusions:

The present study indicated higher parasympathetic activity and BRS with lower SBP variability at rest and during slow breathing in yoga practitioners compared to naive group. Findings indicate that the short-term practice of slow breathing complements the augmented parasympathetic activity and BRS in the yoga group.

Autonomic Tone and Baroreflex Sensitivity during 70° Head-up Tilt in Yoga Practitioners

Introduction:

The intervention of yoga was shown to improve the autonomic conditioning in humans evident from the enhancement of parasympathetic activity and baroreflex sensitivity (BRS). From the documented health benefits of yoga, we hypothesized that the experience of yoga may result in adaptation to the orthostatic stress due to enhanced BRS.

Aim:

To decipher the effects of yoga in the modulation of autonomic function during orthostatic challenge.

Materials and Methods:

This was a comparative study design conducted in autonomic function test lab, of the Department of Physiology, All India Institute of Medical Sciences, New Delhi, India. Heart rate variability (HRV), blood pressure variability, and BRS were analyzed on forty naïve to yoga (NY) subjects and forty yoga practitioners with an average age of 31.08 ± 7.31 years and 29.93 ± 7.57 years, respectively. All participants were healthy. Seventy degrees head up tilt (HUT) was used as an intervention to evaluate the cardiovascular variability during orthostatic challenge.

Results:

During HUT, the R-R interval (P = 0.042), root mean square of succesive R-R interval differences (RMSSD) (P = 0.039), standard deviation of instantaneous beat-to-beat R-R interval variability (SD1) (P = 0.039) of HRV, and sequence BRS (P = 0.017) and α low frequency of spectral BRS (P = 0.002) were higher in the yoga group. The delta decrease in RRI (P = 0.033) and BRS (P < 0.01) was higher in the yoga group than the NY group.

Conclusion:

The efferent vagal activity and BRS were higher in yoga practitioners. The delta change (decrease) in parasympathetic activity and BRS was higher, with relatively stable systolic blood pressure indicating an adaptive response to orthostatic challenge by the yoga practitioners compared to the NY group.

Effect of Bhramari pranayama practice on simple reaction time in healthy adolescents - a randomized control trial

Objectives The improvement in the/reaction time is important, as it is an indicator of cognitive function. Therefore, there is a need, especially for adolescents in the form of techniques or courses that can improve the reaction time. Yoga was found to cause a better improvement in the health of the individuals. The present study intended to show the effects of Bhramari pranayama (Bhr.P) on reaction time in the healthy adolescents. Methods Of the 730 potential subjects screened, 520 apparently healthy adolescents randomly assigned to either the Bhr.P group (n-260) or control group (n-260). Bhr.P group practiced the bhramari pranayama for 3 days in a week for 6 months. The Auditory Reaction Time (ART) and the Visual Reaction Time (VRT) were assessed before and after Bhr.P pranayama practice. Results Bhr.P group shows significant shortening of response time in both VRT (from 267.13 ± 52.65 to 249.87 ± 39.41 ms) and ART (from 237.42 ± 48.12 to 227.91 ± 34.60 ms) after 6 months of Bhr.P practice. In control group subjects, no such significant changes were found (p > 0.05). Conclusions Shortening of RT implies an improvement in the information processing and reflexes. This beneficial effect of Bhr.P on reaction time can be used for improving cognitive function in the adolescents for their academic performances.

Effect of Unilateral Left Nostril Breathing (Chandra Anga Pranayama) on Cognitive Function in Healthy Yoga-Naïve Individuals: A Randomized, Controlled, Pilot Study

INTRODUCTION

Breathing modulates cortical neuronal activity. Various breathing exercises are purported to have specific effects on emotional and cognitive functions.

OBJECTIVE

To determine the effect of unilateral left nostril breathing (ULNB) on nonlateralized, overall cognitive functions using computerized psychometric tests.

METHODS

A randomized, controlled, pilot study was conducted among 20 healthy yoga-naïve medical students. ULNB was performed for 15 min by the test group (n = 10) and breath awareness by the control group (n = 10). Attention and processing speed, memory, and executive function were assessed using the Letter-Digit Substitution Test, Sternberg Memory Task, and Victoria Stroop Test, respectively. Baseline, pre- and postintervention scores were recorded.

RESULTS

There was no significant difference between the groups in baseline scores. In the Sternberg Memory Task, a statistically significant decrease in response time was seen in the test (t(9) = 3.855, p = 0.004) as well as the control group (t(9) = 3.120, p = 0.012); there was no significant difference between the groups. No significant effect of UNLB was seen in the Letter-Digit Substitution Test and Stroop Test.

CONCLUSIONS

Our study showed no difference in the effects of 15-min practice of ULNB and breath awareness on cognitive functions; both improved memory but not attention or executive function.

What Is Meditation? Proposing an Empirically Derived Classification System

Meditation is an umbrella term, which subsumes a huge number of diverse practices. It is still unclear how these practices can be classified in a reasonable way. Earlier proposals have struggled to do justice to the diversity of meditation techniques. To help in solving this issue, we used a novel bottom-up procedure to develop a comprehensive classification system for meditation techniques. In previous studies, we reduced 309 initially identified techniques to the 20 most popular ones. In the present study, 100 experienced meditators were asked to rate the similarity of the selected 20 techniques. Using multidimensional scaling, we found two orthogonal dimensions along which meditation techniques could be classified: activation and amount of body orientation. These dimensions emphasize the role of embodied cognition in meditation. Within these two dimensions, seven main clusters emerged: mindful observation, body-centered meditation, visual concentration, contemplation, affect-centered meditation, mantra meditation, and meditation with movement. We conclude there is no "meditation" as such, but there are rather different groups of techniques that might exert diverse effects. These groups call into question the common division into "focused attention" and "open-monitoring" practices. We propose a new embodied classification system and encourage researchers to evaluate this classification system through comparative studies.

Development of a yoga module targeting cardiovascular health for patients with post-myocardial left ventricular dysfunction in India

BACKGROUND

Yoga is known to contribute towards cardiovascular health. This paper describes the development of a need-based yoga program which is suitable to be integrated into the cardiac rehabilitation of post-myocardial infarction patients with left ventricular dysfunction.

MATERIALS AND METHODS

Based on the assessment of the need of the patients, literature review, and expert opinion, a yoga module was developed using the qualitative method of inquiry. The program included warm-up exercises, yogic asanas, pranayama, meditation and counseling sessions. A structured questionnaire eliciting comments on the contents was given independently to ten experts working in the field of health and yoga for validation. The final module was derived after incorporating the suggestions of the experts.

RESULTS

Using the raters' expertise in cardiology and yoga practice, the practices which constitute the module were optimized. Majority of the experts (raters) agreed with the duration of 1 h training for 1month under supervision as adequate for subsequent practice at home. There was a 0.786 inter-rater reliability estimated using the interclass coefficient (ICC) and 0.789 internal consistency of the questions, measured using Cronbach's alpha. Both values indicate "good" reliability and consistency of the yoga module.

CONCLUSION

The developed yoga module was found to be acceptable. Future randomized control trials will be necessary to validate the effectiveness of this module and if the module demonstrates to be effective by clinical studies, it may add a therapeutic option in the rehabilitation of patients with heart failure following myocardial infarction, which can be applied in the hospitals and community level.

Acute effects on cardiovascular oscillations during controlled slow yogic breathing

Background & objectives:

Breathing exercises are believed to modulate the cardiovascular oscillations in the body. To assess the validity of the assumption and understand the underlying mechanism, the key autonomic regulatory parameters such as heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) were recorded during controlled slow yogic breathing. Alternate nostril breathing (ANB) was selected as the yogic manoeuvre.

Methods:

Twelve healthy volunteers (age 30±3.8 yr) participated in the study. ANB was performed at a breathing frequency of 5 breaths per minute (bpm). In each participant, the electrocardiogram, respiratory movements, beat-to-beat BP and end-tidal carbon dioxide were recorded for five minutes each: before, during and after ANB. The records were analyzed for HRV, BPV and BRS.

Results:

During ANB, HRV analysis showed significant increase in the standard deviation of all NN intervals, low-frequency (LF) component, LF/HF (low frequency/high frequency) ratio and significant decrease in the HF component. BPV analysis showed a significant increase in total power in systolic BPV (SBPV), diastolic BPV (DBPV) and mean BPV. BRS analysis showed a significant increase in the total number of sequences in SBPV and DBPV and significant augmentation of α-LF and reduction in α-HF. The power spectrum showed a dominant peak in HRV at 0.08 Hz (LF component) similar to the respiratory frequency. The acute short-term change in circulatory control system declined immediately after the cessation of slow yogic breathing (ANB) and remained elevated in post-ANB stage as compared to the pre-ANB.

Interpretation & conclusions:

Significant increase in cardiovascular oscillations and baroreflex recruitments during-ANB suggested a dynamic interaction between respiratory and cardiovascular system. Enhanced phasic relationship with some delay indicated the complexity of the system. It indicated that respiratory and cardiovascular oscillations were coupled through multiple regulatory mechanisms, such as mechanical coupling, baroreflex and central cardiovascular control.

Effects of yogic breath regulation: A narrative review of scientific evidence

Pranayama or breath regulation is considered as an essential component of Yoga, which is said to influence the physiological systems. We present a comprehensive overview of scientific literature in the field of yogic breathing. We searched PubMed, PubMed Central and IndMed for citations for keywords “Pranayama” and “Yogic Breathing”. The search yielded a total of 1400 references. Experimental papers, case studies and case series in English, revealing the effects of yogic breathing were included in the review. The preponderance of literature points to beneficial effects of yogic breathing techniques in both physiological and clinical setups. Advantageous effects of yogic breathing on the neurocognitive, psychophysiological, respiratory, biochemical and metabolic functions in healthy individuals were elicited. They were also found useful in management of various clinical conditions. Overall, yogic breathing could be considered safe, when practiced under guidance of a trained teacher. Considering the positive effects of yogic breathing, further large scale studies with rigorous designs to understand the mechanisms involved with yogic breathing are warranted.

The hypotensive effect of Yoga's breathing exercises: A systematic review

The aim of this review was to evaluate the effect of pranayama (Yoga's breathing exercises) on BP and its applicability in the treatment of hypertension. Thirteen trials, assessing acute (eight studies) and chronic (five studies) BP response to pranayama were included. Significant BP reductions after pranayama were found in both acute (2-10 mmHg mean SBP reduction, N = 5 studies; 1 mmHg mean DBP reduction, N = 1 study) and chronic studies (4-21 mmHg mean SBP reduction, N = 3 studies; 4-7 mmHg mean DBP reduction, N = 2 studies). The pranayama's effect on BP were not robust against selection bias due to the low quality of studies. But, the lowering BP effect of pranayama is encouraging. The pranayama with slower rhythms and manipulation of the nostrils, mainly with breaths by the left, present better results when compared with the other types and should be the main pranayama applied when the goal is to reduce blood pressure especially in hypertensive patients.

Effects of Various Prāṇāyāma on Cardiovascular and Autonomic Variables

Cardiovascular functions are controlled by neural factors, temperature, hormones, etc., Of these, neural factors primarily concern the autonomic nervous system, which plays a major role in maintaining and regulating cardiac functions, e.g., blood pressure and heart rate. Prāṇāyāma is one of the most important yogic practices. There are various review articles on Yoga and its effects but, though Prāṇāyāma is a part of yoga, there is lack of review articles. To the best of our knowledge there is no known review article on effect of various Prāṇāyāma on cardiovascular and autonomic variables. To provide a general overview about the effect of various prāṇāyāma (breathing techniques) on cardiovascular and autonomic variables. A narrative review was performed based on the available scientific literature. An electronic data search was performed in Medline/PubMed database to review relevant articles, using keywords such as "Prāṇāyāma, Yogic breathing techniques, Unilateral nostril breathing, Alternate nostril breathing, Kapalbhati, Bhastrika and Bhramari Pranayama". All the relevant articles published from 1988 to 06-04-2016 were included in this review. Slow type of yogic breathing technique was reported to produce beneficial effect on cardiovascular and autonomic variables while fast breathing techniques do not produce such effects. There is lack of consistency in the results of specific nostril yogic breathing techniques and the mechanisms behind the effects of various prāṇāyāma. This review suggests that different types of Prāṇāyāma techniques produce different effects and the mechanisms behind these effects are not fully understood.

A brief qualitative survey on the utilization of Yoga research resources by Yoga teachers

Introduction:

Yoga has become popular worldwide with increasing research done on its therapeutic potential. However, it remains to be determined whether such findings actually percolate down into teaching and practice of Yoga teachers/therapists.

Materials and Methods:

The aim of this survey was to document awareness of Yoga research findings in the Yoga community and find out how these were utilized. It was undertaken with a select group of 34 international Yoga teachers and therapists utilizing email and social media between August and December 2015. Majority of responders had well-established reputation in Yoga and were from diverse lineages with 30 of them having more than 5 years of experience in the field. A set of eight questions were sent to them related to essentiality of Yoga research, how they updated themselves on research findings and whether such studies influenced their teaching and practice. Responses were compiled and appropriate statistics determined for quantitative aspects while feedback, comments and suggestions were noted in detail.

Results and Discussion:

About 89% agreed that it was essential to be up-to-date on Yoga research but only 70% updated themselves regularly with average papers read fully per year being <10. Most accessed information through general news reports, emails from contacts, and articles on internet sites whereas only 7% were through PubMed. About 60% felt these studies helped them in general teaching whereas 20% said that such studies had not really influenced it in any way.

Conclusion:

This survey provides a basic picture of a general lack of awareness of Yoga research amongst practicing Yoga teachers and therapists. Though a majority agree research is important, few seriously update themselves on this through scientific channels. With regard to future studies, most wanted “proof” that could be used to convince potential clients and felt that more qualitative methods should be applied.

Blood pressure and heart rate variability during yoga-based alternate nostril breathing practice and breath awareness

BACKGROUND

Previous research has shown a reduction in blood pressure (BP) immediately after the practice of alternate nostril yoga breathing (ANYB) in normal healthy male volunteers and in hypertensive patients of both sexes. The BP during ANYB has not been recorded.

MATERIAL/METHODS

Participants were 26 male volunteers (group mean age ±SD, 23.8±3.5 years). We assessed (1) heart rate variability, (2) non-invasive arterial BP, and (3) respiration rate, during (a) ANYB and (b) breath awareness (BAW) sessions. Each session was 25 minutes. We performed assessments at 3 time points: Pre (5 minutes), during (15 minutes; for ANYB or BAW) and Post (5 minutes). A naïve-to-yoga control group (n=15 males, mean age ±SD 26.1±4.0 years) were assessed while seated quietly for 25 minutes.

RESULTS

During ANYB there was a significant decrease (repeated measures ANOVA) in systolic BP and respiration rate; while RMSSD (the square root of the mean of the sum of squares of differences between adjacent NN intervals) and NN50 (the number of interval differences of successive normal to normal intervals greater than 50 ms) significantly increased. During BAW respiration rate decreased. In contrast, respiration rate increased during the control state. ANYB and BAW were significantly different (2-factor ANOVA) in RMSSD and respiration rate. BAW and control were different with respect to respiration rate.

CONCLUSIONS

The results suggest that vagal activity increased during and after ANYB, which could have contributed to the decrease in BP and changes in the HRV.