Comparative effect of 12 weeks of slow and fast pranayama training on pulmonary function in young, healthy volunteers: A randomized controlled trial.

CONTEXT: Pranayamas are breathing techniques that exert profound physiological effects on pulmonary, cardiovascular, and mental functions. Previous studies demonstrate that different types of pranayamas produce divergent effects. AIM: The aim was to compare the effect of 12 weeks of slow and fast pranayama training on pulmonary function in young, healthy volunteers. SETTINGS AND
DESIGN: This study was carried out in Departments of Physiology and ACYTER, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry in 2011. SUBJECTS AND METHODS: Ninety one healthy volunteers were randomized into slow pranayama group (SPG), n =29, fast pranayama group (FPG), n = 32 and control groups (CG) (n = 30). Supervised pranayama training (SPG: Nadisodhana, Pranav pranayama and Savitri pranayama; FPG: Kapalabhati, Bhastrika and Kukkriya pranayama) was given for 30 min/day, thrice/week for 12 weeks by certified yoga instructors. Pulmonary function parameters (PFT) such as forced vital capacity (FVC), forced expiratory volume in first second (FEV1), ratio between FEV1 and FVC (FEV1 /FVC), peak expiratory flow rate (PEFR), maximum voluntary ventilation (MVV), and forced expiratory flow25-75 (FEF25-75), were recorded at baseline and after 12 weeks of pranayama training using the computerized spirometer (Micro laboratory V1.32, England).
RESULTS: In SPG, PEFR, and FEF25-75 improved significantly (P < 0.05) while other parameters (FVC, FEV1, FEV1 /FVC, and MVV) showed only marginal improvements. In FPG, FEV1 /FVC, PEFR, and FEF25-75 parameters improved significantly (P < 0.05), while FVC, FEV1, and MVV did not show significant (P > 0.05) change. No significant change was observed in CG.
CONCLUSION: Twelve weeks of pranayama training in young subjects showed improvement in the commonly measured PFT. This indicates that pranayama training improved pulmonary function and that this was more pronounced in the FPG.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

In the recent decades, awareness and interest have increased in yogic techniques that include pranayamas. They are gaining more importance and becoming acceptable to the public as well as scientific community. [1]

As a deep breathing technique, pranayama reduces dead space ventilation and decreases work of breathing. It also refreshes the air throughout the lungs, in contrast with shallow breathing that refreshes the air only at the base of the lungs. [2] Regular practice of pranayama improves cardiovascular and respiratory functions, improves autonomic tone toward the parasympathetic system, decreases the effect of stress and strain on the body and improves physical and mental health. [345] Pulmonary function parameters (PFT) provide important clinical information to identify and quantify the defects and abnormalities in the functioning of the respiratory system. [6] Spirometry is the basic and useful method available for evaluating these PFT. [7] To the best of our knowledge, there has been no study, which compared the effect of slow and fast pranayama training on PFT. In view of the above background, this study was planned to study the effect of 12 weeks of slow and fast pranayama training on PFT in young healthy volunteers.

SUBJECTS AND METHODS

This study was conducted at Puducherry in 2011. The subjects were recruited from the students of various courses conducted in Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry as well as staff, friends, and relatives of them after obtaining approval from JIPMER Scientific Advisory Committee and Ethics Committee (Human Studies). Subjects after meeting the inclusion and exclusion criteria mentioned below were explained the benefits of yoga training and motivated to enroll for the study.

Inclusion criteria

Healthy volunteers of both genders in the age group of 18-30 years.

Exclusion criteria

History of chronic respiratory illness

Subjects on medication

Smokers and alcoholics

Athletes

Any history of previous yoga or bio feedback techniques training in last 1-year.

The purpose of this study, procedures and benefits were briefed to them. The willing participants were randomized into slow pranayama group (SPG) (n = 29), fast pranayama group (FPG) (n = 32), and control group (CG) (n = 30), after getting informed written consent, by simple randomization method using random numbers generated through computer. Average age of the volunteers was 18.58 ± 2.27 (mean ± standard deviation). Among these 91 volunteers, 72 were females and the remaining 19 were males.

The subjects were advised to come at least 2 h after light breakfast and with light clothing. They were instructed to avoid drinking beverages and performing a vigorous exercise 30 min before the recording of parameters. PFT such as forced vital capacity (FVC), forced expiratory volume in first second (FEV1), ratio between FEV1 and FVC (FEV1 /FVC), peak expiratory flow rate (PEFR), maximum voluntary ventilation (MVV), and forced expiratory flow25-75 (FEF25-75) were recorded at baseline and after 12 weeks of pranayama training by using the computerized spirometer (Micro laboratory, V1.32, England).Supervised pranayama training (SPG: Nadisodhana, Pranav pranayama and Savitri pranayama; FPG: Kapalabhati, Bhastrika and Kukkriya pranayama) was given for 30 min/day, thrice/week for the duration of 12 weeks to SPG and FPG by the certified yoga trainer as per the guidelines of Morarji Desai National Institute of Yoga, New Delhi(. Rest of the days, subjects were motivated to practice at their home. CG did not practice any pranayama during the study period. The techniques of fast and slow type of pranayamas were as described in the previous literatures. [89]

RESULTS

The comparison of PFT between baseline and post test is given in Table 1 and Figures 1 and 2. The normality of the continuous data was tested by using Kolmogorov-Smirnov test. After 12 weeks of slow pranayama training PEFR and FEF25-75 were significantly improved (P = 0.02 and P < 0.01, respectively) when compared with the values at baseline. However, other parameters (FVC, FEV1, FEV1 /FVC, and MVV) had shown only a marginal improvement (P > 0.05).

Table 1

Comparison of pulmonary function parameters between baseline and post test among the study groups (mean±SD)

Figure 1

Comparison of peak expiratory flow rate of the study participants after 12 weeks of study period. SPG: Slow pranayama group, FPG: Fast pranayama group, CG: Control group. Analysis done by Student's paired t-test. *P < 0.05, **P < 0.01, ***P < 0.001

Figure 2

Comparison of forced expiratory flow at 25-75% (FEF25-75) of expiratory flow volume (FEF25-75) of the study participants after 12 weeks of study period. SPG: Slow pranayama group, FPG: Fast pranayama group, CG: Control group. Analysis done by Student's paired t-test. *P < 0.05, **P < 0.01, ***P < 0.001

After 12 weeks of fast pranayama training FEV1 /FVC, PEFR, and FEF25-75 were significantly improved (P = 0.02, P < 0.001, and P < 0.001, respectively) compared with the values at baseline. However, other parameters (FVC, FEV1, and MVV) did not show significant (P > 0.05) change. In CG, no significant change was observed in any of the PFT after 12 weeks of the study period.

Comparison of longitudinal changes in PFT is given in Table 2 and Figure 3. The changes in PFT such as MVV and FEF25-75 were found to be statistically significant overall among the three groups (P < 0.05 and P = 0.001, respectively). The value of MVV was increased by 1.85 ± 5.20 on an average in SPG (P = 0.04). However, in FPG and CG, it was decreased by 2.65 ± 7.60 and 3.67 ± 11.92, respectively (P > 0.05).

Table 2

Comparison of the delta changes in pulmonary function parameters among the study groups (mean±SD)

Figure 3

Comparison of Δforced expiratory flow25-75 (difference between posttest and baseline parameters) in the three study groups after 12 weeks of the study period. SPG: Slow pranayama group, FPG: Fast pranayama group, CG: Control group. *With respect to SPG, #with respect to FPG. Analysis done by one-way ANOVA with Tukey post-hoc analysis. *P < 0.05, **P < 0.01, ***P < 0.001. #P < 0.05, ##P < 0.01, ###P < 0.001

Table 2 and Figure 2 demonstrate that on comparing SPG and FPG, significantly higher change was observed only in FEF25-75 parameter in FPG (P = 0.001). Therefore, our results demonstrate that FPG is more effective than SPG on the above-mentioned PFT.

DISCUSSION

Pranayama involves manipulation of breath movement, and the breath is a dynamic bridge between the body and mind. It consists of three phases: Purak (inhalation), Kumbhak (retention), and Rechak (exhalation) that can be practiced in either slow or fast manner. [10] Results of our study demonstrate that there was no significant difference in the baseline values of PFT. Therefore, all the three groups can be considered comparable for this study. Our results indicate that both pranayama practices had beneficial effect on PFT except respiratory pressure parameters, and the effect of fast pranayama was significantly more on FEF25-75, which is in the effort dependent area of a flow-volume curve. Our results are in agreement with previous studies who have reported that yogic practices, including pranayama training produce statistically significant improvement in the commonly measured PFT. [11121314] A study by Joshi et al. has demonstrated that 6 weeks of exclusive pranayama training improves the ventilatory functions in the form of the increase in FVC, FEV1, MVV, and PEFR in healthy subjects. [15] Sivakumar et al. studied the acute effect of deep breathing (2-10 min) and observed an improvement in the PFT parameters in healthy volunteers. [16]

Yadav and Das attributed that improvement in the PFT parameters by yogic practices due to increased respiratory muscle strength, clearing of respiratory secretions and using the diaphragmatic and abdominal muscles for filling the respiratory apparatus more efficiently and completely. Furthermore, the improvement in the PFT parameters may be due to rise in thoracic - pulmonary compliances and broncho dilatation by training in Nadisodhana pranayama. [17] Stimulation of pulmonary stretch receptors by inflation of the lung reflexely relaxes smooth muscles of larynx and tracheo bronchial tree. Probably, this modulates the airway caliber and reduces airway resistance. [13] Previous investigators demonstrated the effect of pranayama on enhancement of the respiratory muscle efficiency and lung compliance due to reduction in elastic and viscous resistance of lung. [18] Furthermore, pranayama acts as stimulus for release of lung surfactant and prostaglandins into alveolar spaces, which increases the lung compliances. [15]

Significantly higher improvement in PFT parameter (FEF25-75) in FPG can be hypothesized to the reason that breathing during fast pranayama requires breath coordination at higher rate and hence, higher rate of respiratory muscle activity. This produces strengthening of the respiratory muscles and therefore, improvement in the effort produced by the subjects.

CONCLUSION

Our results demonstrate that both slow and fast pranayamas are beneficial on most of the tested PFT parameters, and fast pranayama was more effective than slow pranayama. These changes by both pranayama techniques can be attributed to improved autonomic tone toward parasympathodominance resulting in a relaxed state of mind, better subjective well-being and concentration on the task, improved lung ventilation and strength of respiratory muscles. [19]