Yoga breathing through a particular nostril is associated with contralateral event-related potential changes

EEG signatures change during unilateral Yogi nasal breathing

Airflow through the left-and-right nostrils is said to be entrained by an endogenous nasal cycle paced by both poles of the hypothalamus. Yogic practices suggest, and scientific evidence demonstrates, that right-nostril breathing is involved with relatively higher sympathetic activity (arousal states), while left-nostril breathing is associated with a relatively more parasympathetic activity (stress alleviating state). The objective of this study was to further explore this laterality by controlling nasal airflow and observing patterns of cortical activity through encephalographic (EEG) recordings. Thirty subjects participated in this crossover study. The experimental session consisted of a resting phase (baseline), then a period of unilateral nostril breathing (UNB) using the dominant nasal airway, followed by UNB using the non-dominant nasal airway. A 64-channel EEG was recorded throughout the whole session. The effects of nostril-dominance, and nostril-lateralization were assessed using the power spectral density of the neural activity. The differences in power-spectra and source localization were calculated between EEG recorded during UNB and baseline for delta, theta, alpha, beta and gamma bands. Cluster-based permutation tests showed that compared to baseline, EEG spectral power was significantly (1) decreased in all frequency bands for non-dominant nostril UNB, (2) decreased in alpha, beta and gamma bands for dominant nostril UNB, (3) decreased in all bands for left nostril UNB, and (4) decreased in all bands except delta for right nostril UNB. The beta band showed the most widely distributed changes across the scalp. our source localisation results show that breathing with the dominant nostril breathing increases EEG power in the left inferior frontal (alpha band) and left parietal lobule (beta band), whereas non-dominant nostril breathing is related to more diffuse and bilateral effects in posterior areas of the brain.These preliminary findings may stimulate further research in the area, with potential applications to tailored treatment of brain disorders associated with disruption of sympathetic and parasympathetic activity.

Enhancing Executive Control: Attention to Balance, Breath, and the Speed Versus Accuracy Tradeoff

Malleability of executive control and its enhancement through yoga training is unclear. In Study 1, participants (yoga group; n = 27, mean = 23.27 years) were tested on executive control tasks pre- and post-8 weeks of yoga training. The training focused on attention to postural control during yoga asanas and respiratory control during pranayama-breathing (30 min each of postural and breath control training, biweekly). Yoga training was assessed via performance ratings as to how well a posture was executed and by examining errors that reflected inattention/failures in postural and breath control. We also explored whether attentional demands on motor and respiratory control were associated with three components of executive control (working memory, cognitive flexibility, and inhibition) during nine executive control tasks. Partial correlation results revealed that the three components of executive control might be differentially impacted by postural and breath control and selectively associated with either speed or accuracy (except for cognitive flexibility). Attentional demands influenced the link between postural, breath, and cognitive control. In Study 2, comparisons between a yoga group and a gender-matched control group (control group; n = 27, mean = 23.33 years) pointed toward higher working memory accuracy and a better speed-accuracy tradeoff in inhibitory control in the yoga group. A ceiling-practice effect was addressed by examining yoga practice learning (i.e., practice-induced change in postural and breath control reflected in ratings and errors) on executive control performance across two sets of tasks: repeatedly tested (pre- and post-8 weeks) and non-repeatedly tested (post-8 weeks). Attention to motor and respiratory control during yoga might be considered as a potential mechanism through which specific components of executive control in young adults might be enhanced potentially via altering of speed-accuracy tradeoff.

Effect of hot arm and foot bath on heart rate variability and blood pressure in healthy volunteers

Background Though hot arm and foot bath (HAFB) is widely used, a precise physiological response is not reported. Hence, the present study was conducted to evaluate the effect of HAFB on heart rate variability (HRV) and blood pressure (BP) in healthy volunteers. Materials and Methods Sixteen healthy male volunteers' aged 23.81 ± 5.27 (mean ± standard deviation) years were recruited. All the subjects underwent only one session of HAFB (104-degree Fahrenheit) for the duration of 20 min. Assessments such as Electrocardiography and BP were taken before and after the intervention. Results Results of this study showed a significant reduction in systolic-BP (SBP), diastolic-BP (DBP), mean arterial pressure (MAP), the mean of the intervals between adjacent QRS complexes or the instantaneous heart rate (RR interval), the number of interval differences of successive NN intervals greater than 50 ms (NN50), the proportion derived by dividing NN50 by the total number of NN intervals (pNN50), and high frequency (HF) band of HRV along with a significant increase in heart rate (HR), low-frequency (LF) band of HRV and LF/HF ratio compared to its baseline. Conclusions Results of this study suggest that 20 min of HAFB produce a significant increase in HR and a significant reduction in SBP, DBP, and MAP while producing parasympathetic withdrawal.

Effects of 8 weeks of modified hatha yoga training on resting-state brain activity and the p300 ERP in patients with physical disability-related stress

[Purpose] We examined the effects of Hatha yoga on EEG and ERP in patients with physical disability-related stress. [Participants and Methods] Eighteen male and female injured workers with high stress levels, aged between 18 to 55 years, were evenly divided into two groups: untrained (CG) and trained (TG) modified hatha yoga groups. A modified Hatha yoga protocol was designed for this population by two certified yoga instructors, approved by a physical therapist, and conducted for one hour, three times weekly for 8 weeks. [Results] The results indicated a significant increase in alpha EEG activity over the frontal, central, and parietal electrodes and the delta EEG activity over the centroparietal electrode from pre- to post-training in TG. In addition, significantly faster auditory reaction time for target stimuli, as well as lower P300 peak latency of ERP in auditory oddball paradigm were obtained in TG after 8 weeks of yoga training compare to CG. [Conclusion] Changes in brain activity and ERP components following yoga training would support the psychophysiological effects of hatha yoga as an adjunct to routine rehabilitation.

Changes in Reaction Time after Yoga Bellows-type Breathing in Healthy Female Volunteers

Background

Previously, yoga bellows-type breathing (bhastrika pranayama) reduced reaction time (RT) or reduced anticipatory responses in male participants or a mixed group of male and female participants.

Aims

The present study as a control trial aimed to assess the effects of yoga bellows-type breathing on RT in females exclusively.

Methods

The sample consisted of 25 healthy females, aged between 19 and 32 years (group mean ± standard deviation, 22.8 ± 3.5 years). All of them had prior minimum experience of yoga including yoga bellows-type breathing of 12 months. The RT was assessed in each participant before and after three randomized sessions differed in the intervention given held on three separate days. The sessions were (i) YOGA bellows-type breathing or bhastrika pranayama(BHK), (ii) Breath awareness (BAW), and (iii) Sitting quietly (CTL) as a control session. The duration of the intervention was 18 min, and the participants were assessed for RT before and after the intervention.

Results

Repeated measures ANOVA, post hoc tests with Bonferroni adjusted showed that the time taken to obtain a correct response reduced significantly after 18 min of BAW (P < 0.05) and CTL (P < 0.05). However, no changes were seen in the RT after BHK.

Conclusions

The results suggest that different interventions may optimize performance in tasks requiring attention in females compared to males.

Effect of respiratory pattern on automated clinical blood pressure measurement: an observational study with normotensive subjects

BACKGROUND

It has been reported that deep breathing could reduce blood pressures (BP) in general. It is also known that BP is decreased during inhalation and increased during exhalation. Therefore, the measured BPs could be potentially different during deep breathing with different lengths of inhalation and exhalation. This study aimed to quantitatively investigate the effect of different respiratory patterns on BPs.

METHODS

Forty healthy subjects (20 males and 20 females, aged from 18 to 60 years) were recruited. Systolic and diastolic BPs (SBP and DBP) were measured using a clinically validated automated BP device. There were two repeated measurement sessions for each subject. Within each session, eight BP measurements were performed, including 4 measurements during deep breathing with different respiratory patterns (Pattern 1: 4.5 s vs 4.5 s; Patter 2: 6 s vs 2 s; Pattern 3: 2 s vs 6 s; and Pattern 4: 1.5 s vs 1.5 s, respectively for the durations of inhalation and exhalation) and additional 4 measurements from 1 min after the four different respiratory patterns. At the beginning and end of the two repeated measurement sessions, there were two baseline BP measurements under resting condition.

RESULTS

The key experimental results showed that overall automated SBP significantly decreased by 3.7 ± 5.7 mmHg, 3.9 ± 5.2 mmHg, 1.7 ± 5.9 mmHg and 3.3 ± 5.3 mmHg during deep breathing, respectively for Patterns 1, 2, 3 and 4 (all p < 0.001 except p < 0.05 for Pattern 3). Similarly, the automated DBPs during deep breathing in pattern 1, 2 and 4 decreased by 3.7 ± 5.0 mmHg, 3.7 ± 4.9 mmHg and 4.6 ± 3.9 mmHg respectively (all p < 0.001, except in Pattern 3 with a decrease of 1.0 ± 4.3 mmHg, p = 0.14). Correspondingly, after deep breathing, automated BPs recovered back to normal with no significant difference in comparison with baseline BP (all p > 0.05, except for SBP in Pattern 4).

CONCLUSIONS

In summary, this study has quantitatively demonstrated that the measured automated BPs decreased by different amounts with all the four deep breathing patterns, which recovered back quickly after these single short-term interventions, providing evidence of short-term BP decrease with deep breathing and that BP measurements should be performed under normal breathing condition.

Nasal airflow and brain activity: is there a link?

BACKGROUND

Over the past few decades, evidence has emerged suggesting that nasal airflow asymmetry and brain asymmetry are linked. The nose exhibits asymmetrical airflow, with the dominant airflow alternating from one nasal passage to the other over a period of hours. Some authors have suggested a correlation between cerebral hemisphere dominance and nostril dominance. Others have proposed an association between rhythmic fluctuations in nasal airflow and corresponding fluctuations in cerebral hemisphere activity. Based on ancient yoga breathing techniques, newer evidence suggests that altering nasal airflow can influence brain activity, with reports of improved cognitive function caused by unilateral forced nostril breathing. It seems that a nasal airflow stimulus may have an activating effect on the brain, as it has also been shown to trigger seizure activity in epileptic patients.

OBJECTIVES

This article explores these theories in detail, reviews the evidence, and presents new models linking nasal airflow and brain activity.

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.

Mind-Body Practices and the Adolescent Brain: Clinical Neuroimaging Studies

BACKGROUND

Mind-Body practices constitute a large and diverse group of practices that can substantially affect neurophysiology in both healthy individuals and those with various psychiatric disorders. In spite of the growing literature on the clinical and physiological effects of mind-body practices, very little is known about their impact on central nervous system (CNS) structure and function in adolescents with psychiatric disorders.

METHOD

This overview highlights findings in a select group of mind-body practices including yoga postures, yoga breathing techniques and meditation practices.

RESULTS

Mind-body practices offer novel therapeutic approaches for adolescents with psychiatric disorders. Findings from these studies provide insights into the design and implementation of neuroimaging studies for adolescents with psychiatric disorders.

CONCLUSIONS

Clinical neuroimaging studies will be critical in understanding how different practices affect disease pathogenesis and symptomatology in adolescents. Neuroimaging of mind-body practices on adolescents with psychiatric disorders will certainly be an open and exciting area of investigation.

Yoga for correction of lymphedema's impairment of gait as an adjunct to lymphatic drainage: A pilot observational study

INTRODUCTION

Yoga used as a major component of integrative treatment protocol in 14 Indian village camps improved quality-of-life in 425 lymphatic filariasis patients. They experienced better mobility and reduced disability. This paper documents the gait abnormalities observed in lower limb lymphedema patients and the locomotor changes following integrative treatment.

MATERIALS AND METHODS

Yoga postures were performed as explained by traditional yoga practice in two sessions: Before ayurvedic oil massage without compression bandages and after the massage with compression bandages. Each yoga posture lasted for 5 min and the whole session ended in 45 min. Throughout each session, we advised patients to do long, diaphragmatic breathing, concentrating on each breath. The flexion of joints was coordinated with exhalation and extension with inhalation. We educated the patients to do longer expiration than inspiration.

RESULTS AND DISCUSSION

A total of 98 patients (133 limbs) attending the 6(th) month follow-up were evaluated. The most common gait abnormality was antalgic gait. Structural and functional abnormalities were observed in hip, knee and ankle joints. We found that yoga as an adjunct to other components in integrative treatment improved the gait problems. Long standing lymphedema caused altered gait and joint deformities. This was mostly due to inactivity causing muscle weakness and edema within and around the muscles. Both large and small limbs have shown significant volume reduction (P < 0.01) during follow-up after 6 months.

CONCLUSION

There can be a mixed etiology for gait related problems in lymphedema patients. Further studies are recommended to understand the causes of deformities in lymphedema patients and an exact role of yoga.

Characteristics of randomized controlled trials of yoga: a bibliometric analysis

Background

A growing number of randomized controlled trials (RCTs) have investigated the therapeutic value of yoga interventions. This bibliometric analysis aimed to provide a comprehensive review of the characteristics of the totality of available randomized yoga trials.

Methods

All RCTs of yoga were eligible. Medline/PubMed, Scopus, the Cochrane Library, IndMED, and the tables of content of yoga specialty journals not listed in medical databases were screened through February 2014. Bibliometric data, data on participants, and intervention were extracted and analyzed descriptively.

Results

Published between 1975 and 2014, a total of 366 papers were included, reporting 312 RCTs from 23 different countries with 22,548 participants. The median study sample size was 59 (range 8–410, interquartile range = 31, 93). Two hundred sixty-four RCTs (84.6%) were conducted with adults, 105 (33.7%) with older adults and 31 (9.9%) with children. Eighty-four RCTs (26.9%) were conducted with healthy participants. Other trials enrolled patients with one of 63 varied medical conditions; the most common being breast cancer (17 RCTs, 5.4%), depression (14 RCTs, 4.5%), asthma (14 RCTs, 4.5%) and type 2 diabetes mellitus (13 RCTs, 4.2%). Whilst 119 RCTs (38.1%) did not define the style of yoga used, 35 RCTs (11.2%) used Hatha yoga and 30 RCTs (9.6%) yoga breathing. The remaining 128 RCTs (41.0%) used 46 varied yoga styles, with a median intervention length of 9 weeks (range 1 day to 1 year; interquartile range = 5, 12). Two hundred and forty-four RCTs (78.2%) used yoga postures, 232 RCTs (74.4%) used breath control, 153 RCTs (49.0%) used meditation and 32 RCTs (10.3%) used philosophy lectures. One hundred and seventy-four RCTs (55.6%) compared yoga with no specific treatment; 21 varied control interventions were used in the remaining RCTs.

Conclusions

This bibliometric analysis presents the most complete up-to-date overview on published randomized yoga trials. While the available research evidence is sparse for most conditions, there was a marked increase in published RCTs in recent years.

Electronic supplementary material

The online version of this article (doi:10.1186/1472-6882-14-328) contains supplementary material, which is available to authorized users.

Slow yogic breathing through right and left nostril influences sympathovagal balance, heart rate variability, and cardiovascular risks in young adults

Background:

Specific nostril breathing is known to influence autonomic functions.

Aim:

The study was to assess the effects of right nostril breathing (RNB) and left nostril breathing (LNB) on heart rate variability (HRV) and cardiovascular functions.

Material and Methods:

Eighty-five student volunteers were divided into three groups: RNB group (n = 30), LNB group (n = 30), and control group (n = 25). RNB and LNB group subjects practiced right and left nostril breathing, respectively, every day 1 h for 6 weeks. The control group did not practice nostril breathing. Cardiovascular parameters and spectral indices of HRV were recorded before and after 6-week practice of nostril breathing. In RNB and LNB groups, prediction of rate-pressure product (RPP) by low-frequency to high-frequency ratio (LF-HF) of HRV was assessed by bivariate logistic regression.

Results:

HRV indices representing sympathetic activity were increased in the RNB group and indices representing parasympathetic activity were increased in LNB group following 6-week nostril breathing. Prediction of LF-HF to RPP, the marker of cardiovascular risks, was more significant (OR 2.65, P = 0.005) in the LNB group compared to the RNB group (OR 1.452, P = 0.016).

Conclusions:

Short-term practice of LNB improves vagal tone, increases HRV, and promotes cardiovascular health of medical students. Practice of RNB increases sympathetic tone and could jeopardize cardiovascular health.

Exploring the benefits of unilateral nostril breathing practice post-stroke: attention, language, spatial abilities, depression, and anxiety

OBJECTIVE

Unilateral nostril breathing (UNB) is a yogic pranayama technique that has been shown to improve verbal and spatial cognition in neurologically intact individuals. Early study of UNB in healthy individuals has shown benefits for attention and memory. This preliminary study explored whether UNB influenced various measures of attention, language, spatial abilities, depression, and anxiety in post-stroke individuals, both with and without aphasia.

DESIGN

A within-subjects repeated-measures design was used to determine whether UNB improved cognitive, linguistic, and affect variables in post-stroke individuals. Within-subjects comparisons determined UNB's effects over time, and between-subjects comparison was used to determine whether changes in these variables differed between post-stroke individuals with and without aphasia.

SETTING

Athens and Atlanta, Georgia.

PARTICIPANTS

Eleven post-stroke individuals participated in a 10-week UNB program. Five individuals had stroke-induced left hemisphere damage with no diagnosis of aphasia (left hemisphere damage control group; LHD), and six individuals experienced left hemisphere damage with a diagnosis of aphasia (individuals with aphasia group; IWA).

MEASURES

Individuals were assessed on measures of attention, language, spatial abilities, depression, and anxiety before, during, and after UNB treatment.

RESULTS

UNB significantly decreased levels of anxiety for individuals in both groups. Performance on language measures increased for the individuals with aphasia.

CONCLUSIONS

Significant findings for language and affect measures indicate that further investigation regarding duration of UNB treatment and use of UNB treatment alongside traditional speech-language therapy in post-stroke individuals is warranted.

Assessment of the effects of pranayama/alternate nostril breathing on the parasympathetic nervous system in young adults

BACKGROUND AND AIM

Pranayama, the art of breath control, is considered to be the heart of yogic exercises. The present study was performed with the aim of evaluating the effect of Pranayama/Alternate Nostril Breathing (A.N.B.) on the parasympathetic nervous system in healthy young adult males.

METHODS

A comparative account of the expiratioin: inspiration ratio (E:I ratio) and the orthostatic tolerance test (30:15 ratio) at the basal level, at the start of the study and after the practice of A.N.B for 5 minutes and following a training period of 6 weeks.

RESULT AND CONCLUSION

This study showed that the parasympathetic tone was enhanced appreciably in the participants. The observations of this study suggest that the yogic exercise of A.N.B. influences the parasympathetic nervous system significantly.

Science of the mind: ancient yoga texts and modern studies

The practice of yoga is gaining in popularity with a wide range of practices. Recent research and descriptions from the ancient texts are often concurrent with regard to the effects of the practice, taking into account expected differences between modern scientific terms and those used in the original texts. Voluntarily regulated yoga breathing practices form a bridge between physical and mental changes. The voluntarily regulated yoga breathing has distinct effects on metabolism, the autonomic nervous system, higher brain functions, and mental state. The effects of meditation on the nervous system and mental state are even clearer.