Effect of Bhrāmarī Prāṇāyāma Practice on Pulmonary Function in Healthy Adolescents: A Randomized Control Study.

CONTEXT: Prāṇāyāma, the fourth limb of ancient aṣṭāṅga yoga consists of breathing techniques which produce various physiological and psychological effects. Though various types of prāṇāyāma and their effects have been scientifically established, Bhrāmarī prāṇāyāma (Bhr.P) is the one whose effects still remain understated. AIMS: The present study was conducted to find the effects of Bhrāmarī prāṇāyāma practice on pulmonary function in healthy adolescents. STUDY
DESIGN: Randomized control trial. SUBJECTS AND METHODS: 90 healthy adolescents including 32 females and 58 males participated in the study. They were randomly divided into Bhr.P group (n = 45) and Control group (n = 45) by a simple lottery method. Pulmonary function test was done at baseline and at end of 12th week using RMS Helios spirometry. Prāṇāyāma group students were trained to do Bhr.P as 3 to 4 breaths/min for 5 min followed by 2 min rest. This was one cycle and in this way, they were instructed to do five cycles each time for 45 minutes five days in a week. Control group students were not allowed to practice any kind of exercise throughout the study period. STATISTICAL ANALYSIS: Student paired and unpaired T tests were used to analyse the intra group and intergroup differences using R statistical software.
RESULTS: A significant (P < 0.05) improvement in all pulmonary function parameters; FVC, FEV1, FEV1/FVC ratio, FEF 25%-75% and PEFR was seen in the Bhr.P group than the control group adolescents. Slow vital capacity (SVC) and Maximum Voluntary Volume (MVV) also showed significant improvement in the prāṇāyāma group.
CONCLUSIONS: Bhrāmarī Prāṇāyāma practice is effective in improving the pulmonary function among the adolescents which could be utilized for further clinical studies.

Introduction

Yoga originated in ancient India and denotes union between the individual self and the transcendental self. Prāṇāyāma is an important aspect of yoga that mainly deals with the relationship between breathing pattern and emotional states.[1] As the fourth limb of Aṣṭāṅga yoga, it is very effective and important component of yoga training. It can assume more complex forms of breathing, but the essence of its practice remains slow and fast breathing.[2] Nāḍi śodhana, Kapālabhāti, Bhastrikā, Śītalī and Bhrāmarī are the important and most practiced types of prāṇāyāma among practitioners. Regular practice of prāṇāyāma improves cardiovascular and respiratory functions, improves cognitive function, decreases the effect of stress and strain on the body and hence improves the physical and mental health of an individual.[345] The Bhrāmarī Prāṇāyāma (Bhr.P), in specific, is one such ancient yogic breathing practice that not only includes a unique breathing technique but also is associated with concurrent generation of a constant humming sound during the phase of expiration thus placing the body in the state of relaxation. Studies done by Jain et al. and Rampalliwar et al. have concluded that regular practice of Bhr.P reduces the cardiovascular reactivity to stress (cold pressor test) by inducing parasympathetic predominance and cortico-hypothalamo medullary inhibition.[67] Immediately after the practice of Bhr.P, there is a reduction in heart rate, blood pressure[8] and improvement in the cognition in healthy subjects.[9] On the other hand, increased theta activity[10] and Paroxysmal Gamma wave[11] following the Bhr.P has been noted to induce positive thoughts and feeling of happiness. It can be used for managing tinnitus as a self-induced sound therapy.[12] Though studies have been done on some of the beneficial effects of Bhr.P, its several other effects still remain unexplored. As a deep breathing technique, this Prāṇāyāma practice reduces the physiological dead space ventilation and decreases the work of breathing. It makes efficient use of the diaphragm and abdominal muscles which improve the pulmonary function.[13] This could be assessed using the pulmonary function test (PFT) that provides important clinical information to identify and quantify the defects and abnormalities in the functioning of the respiratory system.[14] Spirometry is one basic, simple and non invasive method available for evaluating pulmonary function.[15] Individual and combined beneficial effect of different prāṇāyāmas has been studied both in healthy as well as diseased people and well reported with sound scientific basis.[161718192021] However, from our knowledge there are no randomized control trails available on effects of Bhr.P on pulmonary function. The present study was planned to study the effects of Bhr.P on pulmonary function in healthy adolescents.

Subjects and Methods

Subjects

90 apparently healthy adolescents of both sex (52 males and 38 females with mean age 15 ± 2.4 yrs, height 156.24 ± 25.33 cm and weight 51.25 ± 4.56 kg participated in this study. Institutional ethical clearance (IEC-NI/14/JAN/38/07) was obtained before commencement of the experiment. Permission from the principal of the concerned school was also obtained. Written informed consent was obtained from the parents after explaining the procedure clearly and completely. Separate assent was obtained from the students for their voluntary participation in the study. Personal history (name, age, gender) followed by general, clinical and respiratory system examination was done. Students were excluded based on the exclusion criteria that included wheezing, congenital cardiac disorders, history of any acute illness three months prior to study, surgeries in the recent past, smoking, any form of regular exercise, active sports person/athletes and previous exposure to yoga training.

Following the inclusion and exclusion criteria, students were recruited for the study. After inclusion, they were randomly divided into control group (n = 45) and Bhr.P group (n = 45) by a simple lottery method. Control group students did not receive any form of exercise and Bhr.P group students practiced Bhr.P as per the protocol.

Intervention protocol

Bhr.P practice was taught to the subjects by qualified yoga doctors as per standard method.[22] They were allowed to sit in any comfortable sitting posture and with closed eyes. Each subject was directed to inhale slowly up to their maximum through both the nostrils and then to exhale through both the nostrils slowly up to the maximum. During exhalation, the subject was asked to pronounce the word “OM” with a humming nasal sound mimicking the sound of a wasp, and to mildly vibrate the laryngeal walls and the inner walls of the nostril. These steps complete one cycle of Bhr.P (respiratory rate 3-4/min followed with one min rest).In this way, the subjects were made to do the prāṇāyāma for five days in a week up to 12 weeks in the evening between 3 pm to 4 pm. Each time they did the prāṇāyāma, they had to do 3-6 breaths/min for 5 minutes followed by 2-minute rest. This was considered as one cycle and it was repeated 5 times (5 cycles).

Assessments

Anthropometrical variables, standing height, weight were recorded and BMI was calculated. Pulmonary function tests (PFT) were performed using RMS Helios 401. Calibration was done on the site before each testing session. All subjects performed spirometry in standing position with their nose closed by nose clips. Minimum of three trials were performed by each subject and best of the three was selected for the use.[23] The spirometry parameters measured were: forced vital capacity (FVC), forced expired volume in 1 sec (FEV1), FEV1 to FVC ratio (FEV1/FVC), peak expiratory flow (PEF), mean forced expiratory flow during the middle half of FVC (FEF 25–75%), Slow vital capacity (SVC) and Maximum Voluntary Volume (MVV).

Statistical analysis

Data was expressed as Mean ± SD. Unpaired and paired t-test was done to compare the intergroup and intra group comparison of the spirometry parameters using R statistical software. P < 0.05 was set as significant.

Results

Table 1 shows the anthropometric and resting cardiovascular parameters in Bhr.P group and control group. In both the groups, all parameters were not significantly differing and were comparable. Baseline lung function parameters [Table 2] in the both groups did not show any significant difference. The independent t-test was used to find the changes in between the groups. It showed significant (P < 0.05) improvement in all the lung function parameters like FVC (P = 0.021), FEV1 (P = 0.0319), FEV1/FVC ratio (P = 0.008), FEF 25%-75% (P = 0.029), PEFR (P = 0.0142), SVC (P = 0.0198) and MVV (P = 0.0368) in Bhr.P group after 12 weeks of practice. Effect size (Cohen’s d) was found to be in between medium to large (>0.40) in Bhr.P group after 12 weeks of practice.

Table 1

Anthropometric and cardiovascular parameters of Bhrāmarī prāṇāyāma group and control group

Table 2

Comparison of effect of 12 weeks Bhrāmarī prāṇāyāma on lung function parameters

Discussion

The present study was conducted to find the efficiency of Bhr.P practice on pulmonary function among the healthy adolescents. There was a significant improvement in pulmonary function parameters such as FVC, FEV1, FEV1/FVC ratio, FEV 25-75%, PEFR, MVV and SVC after 12 weeks of prāṇāyāma practice in the study group compared to the controls. When the lungs inflate nearer to total lung capacity by deep yogic breathing, it releases surfactants and prostaglandins into the alveolar space. This will, in turn, increase the lung compliance and decrease bronchial smooth muscle tone, thereby increasing total lung capacity and volume.[24] In addition, this inflation of the lungs stimulates the pulmonary stretch receptors which reflexively relax the smooth muscles of the larynx and tracheobronchial tree. This, in turn, modulates the airway caliber and reduces airway resistance and probably this could be one of the possible reasons for the improvement in PEFR after prāṇāyāma practice.[25] The strengthening of inspiration and expiration respiratory musculature among regular prāṇāyāma practitioners could result in improving the FVC significantly.[26] The increased MVV may be attributed to the involvement of voluntary prolongation of inspiration and expiration during prāṇāyāma that stretches the respiratory muscles to their full extent thus enabling the respiratory apparatus to work to their maximum capacity.[27] Improvement of respiratory muscle function lowers the relative load on the muscles and increases the maximum sustained Ventilatory capacity.[28] All the alveoli of both the lungs open out evenly and this even expansion of all the alveoli enhances the total vital capacity (VC) in the adolescents by the vertical breathing which is the main advantage of the yogic breathing.

Prāṇāyāma is essentially a breathing exercise against resistance and their positive effects on lung functions are well documented.[2930] A study conducted by Mandanmohan et al., suggests that 6 months of yoga training has a favourable effect on the respiratory muscle strength and pulmonary function in an adolescent subject that supports our findings as well.[31] The possible reason for the present observation could be that during prāṇāyāma, the compliance of the lung thoracic system increases and the airway resistance decreases and the efficient movement of the diaphragm in deep breathing leads to improvement in FEVs and FVC capacities.[32] Similar studies were done previously on various prāṇāyāma practices individually in healthy and diseased conditions but the present study is the first one documenting the efficiency of Bhr.P in lung function in adolescents. In today’s modern industrial societies most of the children and adolescents do not have proper physical activity and this leads to an increased risk of cardio-respiratory and other lifestyle-related diseases later in their adulthood.[33] Since in this study, Bhr.P practice has shown significant improvement in pulmonary function among adolescents, it could be utilized for further clinical studies.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Conclusions

This study illustrates that the practice of Bhr.P on a regular basis improves the lung function in healthy adolescents. However further studies on larger number of individuals with a long duration follow-up is required to substantiate the findings.

Financial support and sponsorship

Grant in aid from Sri Ramachandra University under N.P.V Ramasamy Udayar Research fellowship.

Conflicts of interest

There are no conflicts of interest.