Natl. J. Physiol. Pharm. Pharmacol. (2025), Vol. 15(3): 224-233

Original Article

10.5455/NJPPP.2025.v15.i3.2

Effect of a 6-week combined protocol of Bhastrika Pranayama and Nadishodhana Pranayama on dynamic lung function indices of young adults

Dipak Kumar Dhar^1*, Abha Shrivastava², Somlata Jha³, Parvinder Kaur Saini⁴ and Shakti Chauhan⁴

¹Associate Professor, Department of Physiology, Faculty, Department of Medical Education, NMC Regional Center for Medical Education Technologies, Himalayan Institute of Medical Sciences, Swami Rama Himalayan University, Jolly Grant, Dehradun, India

²Professor and Head, Department of Physiology, Himalayan Institute of Medical Sciences, Swami Rama Himalayan University, Jolly Grant, Dehradun, India

³Assistant Professor, Yoga Science and Holistic Health, Himalayan School of Yoga Sciences, Swami Rama Himalayan University, Jolly Grant, Dehradun, India

⁴Tutor, Department of Physiology, Himalayan Institute of Medical Sciences, Swami Rama Himalayan University, Jolly Grant, Dehradun, India

*Corresponding Author: Dipak Kumar Dhar. Associate Professor, Department of Physiology, Faculty, Department of Medical Education, NMC Regional Center for Medical Education Technologies, Himalayan Institute of Medical Sciences, Swami Rama Himalayan University, Jolly Grant, Dehradun, India. Email: dhardkd90 [at] gmail.com

Submitted: 20/12/2024 Accepted: 09/02/2025 Published: 31/03/2025

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Abstract

Background: Emerging research shows that yoga has manifold effects on the physiological functioning of various organ systems. “Pranayama” or yogic breathing techniques forms one of the fundamental components of the classical eight-fold path of yoga or “Ashtanga Yoga”. Literature shows that these breathing practices affect the ventilation of the lungs, gaseous exchange, and even chemoreceptor sensitivity. The dynamic lung function indices affected by pranayama vary widely among studies. The regimens of pranayama also show extensive variation. There have been also very few attempts at quantifying the extent of change. All these factors necessitated the present study.

Aim: The aim of the study was to observe the effect of the combined practice of Bhastrika pranayama (fast breathing, vitalizing pranayama) and Nadishodhana pranayama (slow, alternate nostril breathing, and cooling pranayama) on the dynamic lung function indices over 6 weeks in young adults. It also sought to quantify the extent of the change.

Methods: A prospective cohort study was conducted with 21 randomly selected young, healthy volunteers. Their anthropometric parameters and baseline dynamic lung function tests [Forced Vital Capacity (FVC), Forced Expiratory Volume in 1st sec (FEV₁), FEV₁/FVC ratio, Peak Expiratory Flow Rate (PEFR), and forced expiratory flow 25%–75%] were recorded by digital spirometer RMS Helios 401. The subjects then performed Bhastrika pranayama (for 10–15 minutes) and Nadishodhana pranayama (for 5–10 minutes) for 6 days a week for 6 weeks under the guidance of a certified yoga instructor. The spirometric measurements were repeated after 6 weeks. The comparison was done using a paired t-test. The extent of change was also calculated. Multiple linear regression analysis was used to find out predictor variables that could significantly predict the final value. p-value < 0.05 was considered statistically significant.

Results: The mean FVC increased from 88.57% ± 10.53% to 91.86% ± 9.32 % and PEFR increased from 96.95% ± 18.27% to 102.81% ± 19.18 %, respectively. The changes were statistically significant. Other parameters did not show a significant change.

Conclusion: The present study showed that these yogic breathing practices could bring about a small but statistically significant improvement in both the volume as well as ease of airflow in the respiratory system, which indirectly reflects the mechanical properties of the lungs and chest wall. Importantly, this effect was seen by devoting just around 20 minutes per day for 6 weeks making it a doable practice in our fast-paced world.

Keywords: Bhastrika pranayama, Nadishodhana, Dynamic Lung function, spirometric indices, Yoga.

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Introduction

Yoga is an ancient Indian philosophy and science that aims at the holistic well-being of the human body, pertaining to the physical, mental, emotional, and spiritual dimensions of health. Yogic literature describes a variety of practices for a healthy life. “Yoga” means union, and it aims to attain a union of body, mind, and spirit, which in terms of modern medicine would imply a state of synchronization or harmony between the various organ systems of the body, otherwise known as homeostasis (Bijlani and Manjunatha, 2011; Pal et al., 2019). Homeostasis refers to a state of equilibrium or constancy of the “milieu interieur” and is a fundamental premise of human physiology (Sircar, 2014).

Pranayama is one of the elements of the classical eight-fold path of yoga or “Ashtanga Yoga” as described by Maharishi Patanjali in his “Yoga Sutras” or aphorisms. The word pranayama in Sanskrit derives its meaning from “prana” which means vital force or “life energy” and “ayama” means control. Therefore, pranayama means control of vital force or life energy, which is achieved by consciously regulating one’s breath in certain ways (Muktibodhananda, 1998; Swami, 2008). Pranayama or yogic breathing techniques can be broadly classified into balancing, vitalizing, and tranquilizing practices. Balancing practices aim to achieve a balance between the ida and pingala nadir, which translates to sympathovagal balance. Vitalizing practices seek to activate pranic movement or the sympathetic nervous system and hence also generate heat. Tranquilizing practices seek to simultaneously pacify the system and increase awareness. They activate both the parasympathetic nervous system and the central nervous system (Muktibodhananda, 1998). In terms of the mechanics of breathing, the practices are either slow or fast breathing techniques. Common to all breathing techniques as per yogic literature are three phases- “Puraka” (inhalation), “kumbhaka” (retention), and “rechaka” (exhalation) (Muktibodhananda, 1998; Saraswati, 2002).

Studies have shown that slow and fast breathing has different effects on the autonomic nervous system. Slow breathing such as Nadishodhana, Savitri, and Dirgha, increases the tone of the parasympathetic nervous system (Manaspure et al., 2011). On the other hand, fast or high-frequency breathing practices like Bhastrika and Kapalbhatiare proposed to increase the activity of the sympathetic nervous system and enhance overall ventilation of the lungs because it engages the diaphragm, abdominal, and intercostal muscles in strong contractions (Makwana et al., 1988; Raghuraj et al., 1998). Research exploring the effect of alternate nostril breathing found that breathing techniques initiated with the left nostril had parasympathomimetic effects, whereas those initiated with the right nostril had sympathomimetic effects on the body (Bhavanani et al., 2014). Modern scientific research has revealed that pranayama exerts a beneficial effect on cardiopulmonary health, cognitive function, antioxidant levels, stress levels, and the overall autonomic balance of the body (Singh et al., 2010; Bijlani and Manjunatha, 2011; Veerabhadrappa et al., 2011; Yadav, 2015; Hakked et al., 2017).

Although most studies seem to suggest that yoga promotes improvements in various aspects of lung function (Joshi et al., 1992; Abel et al., 2013; Karthik et al., 2014; Chetry et al., 2023), they differ in the dynamic lung function indices that registered an increase. Some authors have reported that pranayama causes improvement only in the Peak Expiratory Flow Rate (PEFR), which denotes the ventilatory mechanics of the larger airways (Reddy et al., 2015), while others have found betterment in all indices like Forced Vital Capacity (FVC), PEFR, and Forced Expiratory Volume in 1st sec (FEV₁) (Makwana et al., 1988; Abel et al., 2013). Although most studies do not report any changes in the smaller or peripheral airways, one study found that pranayama caused improvement in the ventilation of smaller airways measured in terms of forced expiratory flow (FEF) 25%–75% (Shankarappa et al., 2012). The physiological implications and determinants of each dynamic lung function index are different. The reported studies vary in terms of the pranayama employed, the duration of each session, and the duration of the study. Contrary to common perception, a study investigating the effect of three yogic breathing practices—Dirkha (slow), Kapalbhati (fast), and Bhastrika (fast) did not show any statistically significant improvement in dynamic lung function tests (Seltmann et al., 2020). A systematic review concluded that yoga can improve pulmonary function after a minimum duration of 10 weeks of regular practice (Abel et al., 2013). A study comparing the effects of slow and fast breathing techniques found that respiratory pressures and endurance increased with slow pranayama but not the latter (Madanmohan et al., 2005).

It is evident that much variability exists beneath the surface notion that lung function can be improved through yoga. This necessitated further exploration in the form of the present study. A combined regimen of fast (vitalizing, Bhastrika pranayama) and slow (balancing, Nadishodhana pranayama) breathing practice was used to assess whether individual benefits, as described in the literature, could be observed together or not. Very few studies have used this combined approach. The study also aimed to determine whether the practice of approximately 20 minutes per day could bring about a significant change or not because, in today’s fast-paced world, time availability is an important factor. The aim of this study was to quantify the change observed in dynamic lung function capacities after 6 weeks.

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Materials and Methods

A prospective cohort study was carried out on healthy young volunteers in the Department of Physiology over a period of 6 months from October 2023 to March 2024. The sample size was calculated using G-power (version G*Power 3.1.9.2) which is a validated and reliable software used for the computation of sample size (Erdfelder et al., 1996; Kang, 2021). A priori type of power analysis was selected and conventional input parameters for paired t-test (which is the statistical test of choice for the study), were fed into the software. It included α-error probability (0.05), power of the study (0.95), effect size (0.90), and two-tailed analysis, respectively. The effect size was calculated from a previous study which showed a significant increase in spirometric indices after Bhastrika pranayama (Baseline FVC=2.52 ± 0.61 l and Post yoga FVC=3.48 ± 1.22 l) (Budhi et al., 2019). The minimum sample size came out to be 18. However, to compensate for possible dropouts during the study period, we kept a provision of an additional 50% (18 + 9=27). Therefore, the study was conducted with 27 subjects of both genders. There were 11 male and 16 female participants. A convenience sampling technique was used to select the subjects. Prior approval was obtained from the Institutional Ethics Committee (vide letter no HIMS/RC/2023/187). Informed consent was obtained from all subjects prior to study participation.

Selection criteria

The inclusion criteria were young adults, aged between 18 and 25 years who were willing to perform yogic breathing practices for a minimum of 6 weeks. Subjects who had a history of smoking, alcoholism, or any form of substance abuse, any existing disease states like hypertension, diabetes, cardiac diseases or obstructive and restrictive airway disease, deformities of the thoracic cage or spine, or history of medications were excluded from the study. Subjects who were on any form of physical training (aerobic or resistance) or prior yogic training were also excluded as these could have confounding effects. During the duration of the study, subjects who were not compliant or had poor attendance during the sessions were also excluded from the final analysis of data and considered dropouts from the study.

Methodology

Anthropometric parameters and body mass index (BMI):The height of the subjects was measured barefooted in centimeters to the nearest 0.1 cm. The subjects were asked to stand erect with their head in the Frankfurt horizontal plane and back against the wall. Two readings were taken for each subject and their average was recorded as the height. Weight was recorded to the nearest 0.1 kg by standing on a weighing machine (KRUPS, Mfg. by Doctor Beli Ram & Sons) after removing shoes and wearing only light clothes. Gadgets like wrist watch, mobile phone, and so on, were also removed before recording. Two readings were taken, and their average was recorded as the weight of the subject (Marwaha et al., 2011; Keshavachandran et al., 2012). Their BMI was calculated using Quetlet’s index (BMI=Weight in kg/ Height in metres²) (Garrow and Webster, 1985).

Measurement of pulmonary functions: Digital spirometer RMS Helios 401 (ISO 9001:2015, EN ISO 13485: 2016) was used to record the dynamic lung function tests in sitting posture (Miller et al., 2005). The subjects were advised to have adequate overnight sleep and avoid tea, coffee, and so on, before the recording sessions. Subject’s details like age, sex, anthropometric parameters, and so on, were entered into the software. FVC maneuver was used. The subject was made to sit erect, chin slightly elevated and shoulders slightly back, and then asked to inhale rapidly and completely from the functional residual capacity (end-expiratory position) and exhale as hard and fast as possible into the mouthpiece of the device and continue until no more air could be breathed out. This was immediately followed by another deep breath back in, with the mouthpiece still in his/her mouth, until the lungs were full (Graham et al., 2019). The best of three such attempts were saved as the reading of the subject as per the guidelines of the American Thoracic Society. Before recordings, a demonstration of the procedure was given (Miller et al., 2005; Pellegrino et al., 2005). The parameters were recorded once at the start of the study and again after 6 weeks of pranayama. The recordings were made at a fixed time of the day, in the morning hours at around 10 AM. Appropriate hand hygiene and infection control practices were adhered to as per standard protocols of the American Thoracic Society. Subjects were also instructed to avoid smoking, exercise one hour before the recordings, and use clothing that did not restrict chest and abdominal wall expansion. The calibration of the spirometer was also checked regularly as per the manufacturer’s directions. The lung functions were expressed as a percentage of the predicted normal values for a subject’s age, height, weight, and ethnicity to eliminate the confounding effect of variables like height, weight, sex, and ethnic differences as per standard guidelines (Ruppel, 1991). The predicted normal values were derived using regression equations from large population-based surveys conducted as part of the Global Lung Function Initiative Network covering various ethnic groups worldwide (Stanojevic, 2022).

Practice of pranayama: After the baseline recordings were completed, two breathing practices were performed for the participants. Then, they were regularly performed by the subjects under the supervision and instructions of a certified yoga instructor. They were practiced for approximately 20 minutes for 6 days a week for 6 weeks. The yoga sessions were held in the evening at 4:30 p.m. in the Department of Physiology, Himalayan Institute of Medical Sciences.

Bhastrika pranayama: The subjects were seated in a meditative posture with their back, neck, and head straight. It began with a deep inspiration followed by a rapid expulsion of breath, followed by one another in quick succession. After 20 such expulsions, the final expulsion was followed by deep inspiration. After this, the breath was held for as long comfortably, followed by a slow, deep exhalation. This constituted one round of Bhastrika (Muktibodhananda, 1998; Saraswati, 2002). Three such rounds were practiced with a gap of 1–2 minutes in between. The total duration of Bhastrika Pranayama practice was approximately 10–15 minutes.

Nadishodhana pranayama: This breathing technique is slow, relaxing, rhythmic, and alternate nostril breathing. The subjects were seated in Sukhasana, with eyes closed and nasika mudra. The process started with inhalation through the left nostril, closing the right, followed by exhalation through the right. This was followed by repeating the same steps beginning through the other nostril. This comprised one round (Muktibodhananda, 1998; Iyengar, 2005). This was done alternately for approximately 5–10 minutes.

Follow-up: During the period of 6 weeks, 6 students (i.e., around 22% of the enrolled strength of subjects) were lost as drop-outs from the study due to various reasons like non-compliance, irregularity, and unwillingness to continue further. They were not considered in the final statistical analysis. As the minimum required sample size was 18, the attrition of the subjects described above did not affect the statistical robustness of the study.

Statistical analysis

Data were analyzed using SPSS version 17 (Manufactured by SPSS Inc., Chicago), and a p-value < 0.05 was considered statistically significant. The spirometric indices were expressed in terms of mean ± SD after applying descriptive statistics. The values at baseline and follow-up were compared by paired t-test. The variables that showed a significant change were further analyzed using multiple linear regression to determine the strength of the association and quantify the nature of the effect. Model accuracy or “goodness-of-fit” was expressed in terms of adjusted R².

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Results

The study started with twenty-seven subjects (11 male and 16 female), but there was a drop-out of around 22%. Finally, 21 subjects completed the duration of the study. There were 9 male and 12 female subjects. The mean anthropometric parameters of the participants are presented in Table 1. The mean age and BMI were 18.81 ± 1.37 years and 22.89 ± 3.75 kg/m², respectively. The mean BMI was within the normal range. The mean spirometric parameters of the participants before and after 6 weeks of pranayama are presented in Table 2. As shown in Table 3, a marginal increment was observed in FVC and PEFR, and both of these changes were statistically significant. Marginal decrements were observed in FEV₁, FEV₁/FVC ratio, and FEF _25%–75% although none of these changes were statistically significant. The percentage of improvement upon baseline values in the two indices that showed a significant change is shown in Figure 1. Multiple linear regression analysis was used to understand if changes in these two spirometric indices could be predicted significantly by their baseline spirometric indices and BMI. The standardized B coefficients and adjusted R² values of the regression model are shown in Table 4. The regression models obtained are as follows: Final FVC=44.073 + 0.758 * (Baseline FVC) 0.205 * (BMI), Final PEFR=6.372+ 0.895 * (Baseline PEFR) + 0.046 (BMI). The baseline spirometric values appeared to be a significant predictor (p-value < 0.001) for both.

Table 1. Anthropometric parameters of the participants.

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Discussion

The present study showed that a combined regimen of Bhastrika Pranayama for about 10–15 minutes followed byNadishodhana Pranayama for 5–10 minutes done for 6 weeks, produced a small but significant increase in FVC (4%) and PEFR (6%). Other parameters did not show any significant change. The findings align with similar studies by other authors which point towards a general consensus that pranayama improves respiratory functions (Prakash et al., 2007; Chetry et al., 2023). However, there are variations in the spirometric indices that underwent a significant change. Reddy et al. (2015) used a combined regimen of various yogic breathing practices for 9 weeks, some of which were fast (Bhastrika, Kapalbhati, Surya-bhedi) and some of which were slow (Nadishodhana, Anulom-Vilome, Ujjayai, and Chandra-bhedi pranayama). They reported a statistically significant increase in PEFR but not in FVC. Some of the earliest studies on the effect of yogic breathing practices by Udupa et al. (1975) and Gopal et al. (1973) showed greater vital capacity (VC), more tidal volume (TV), and lesser respiratory rate among the subjects. Karthik et al. (2014) in their study also used a combined regimen of fast and slow breathing along with “Surya namaskar” and reported a significant enhancement of VC, TV, expiratory reserve volume (ERV), PEFR, and breath-holding time. Makwana et al. (1988) in a similar study found an improvement in FVC and PEFR. Shankarappa et al. (2012) also reported improvement in FVC, FEV₁, FEF _25%–75%, and PEFR. A similar study reported greater breath-holding time among the participants (Manaspure et al., 2011). A literature review by Abel et al. (2013) concluded that regular practice of yogic breathing resulted in improvements in FVC, FEV₁, and PEFR which slightly differed from our study as we did not observe a significant change in FEV₁. Quite contrary to the present study, a 3-week combined regimen of three yogic breathing practices—Dirgha (slow), Kapalbhati (fast), and Bhastrika (fast) did not show any statistically significant improvement in dynamic lung function tests (Seltmann et al., 2020).

Table 2. Comparison of mean spirometric indices (percent-predicted values) before and after yogic breathing practices.

Table 3. Comparison of spirometric indices at baseline and after 6 weeks of pranayama between males and females.

Studies exploring the effect of only Bhastrikapranayama also have a lot of variability in the findings. Budhi et al (2019) in a comparative study between groups performing Bhastrika pranayama and running found that all dynamic lung function indices were significantly better in the yoga group. However, Santanella et al. (2011) observed an increase in FEV₁ only which differs from our study. A study done on post-COVID patients showed that a 6-week regimen of Bhastrika pranayama resulted in a significant increase in FVC and FEV₁ (Srinivasan et al., 2021). Bal et al. (2015) in a similar study reported a significant increase in static lung volumes like TV, expiratory reserve volume, inspiratory reserve volume, and VC. Studies exploring the effect of Nadishodhana pranayama only show that both VC and PEFR significantly improved (Joshi et al., 1992; Subbalakshmi et al., 2005; Garg and Chandla, 2016). Studies exploring other aspects of pulmonary functions show thatBhastrika pranayama reduced end-tidal O₂ tension and lowered central chemosensitivity (McKay et al., 2016). It also resulted in a betterment in maximal oxygen consumption (Bal, 2015; Shirodkar et al., 2019).

Most of the studies mentioned in the preceding discussion suggest an improvement in lung functions which further validates our study. Although there were variations in the parameters, this could be attributed to numerous factors. The type of pranayama used, length of each session, number of sessions done per day, study duration after which effects were observed, and even characteristics of the participants like age, baseline fitness levels, disease state, and so on, varied from study to study.

Fig. 1. Percentage improvement upon initial values observed in FVC and PEFR.

Table 4. Regression analysis to determine effect of baseline spirometric indices and BMI on the final effect observed after 6 ns of pranayama.

Spirometry is a test of the ventilatory function of the lungs. It measures the rate at which the lung changes volume during defined breathing maneuvers. FVC is the maximal volume of air exhaled with a maximal forceful effort from a maximal inspiration. It is a highly unique, individualized, and reproducible test because, during expiration, there is a limit to the maximal flow that can be achieved at a given lung volume. PEFR is the maximum expiratory flow rate achieved from a maximum forced expiration, starting without hesitation from the point of maximal lung inflation. It is usually reached within the first 10%–15% of forced exhalation and specifically reflects the flow and patency of the larger or central airways (Murray 1981; Miller et al., 2005; Hyatt Robert et al., 2009). The amount of air that can be accommodated within the lung during inspiration affects the amount that is exhaled during the test. This, in turn, is influenced by the strength and performance of the respiratory muscles and the mechanical properties of both the lung and chest wall like compliance, elasticity, size of airways, and resistance to air flow. Airway resistance specifically determines the ease of expiration and hence the expiratory flow rate and volume (Barrett et al, 2012; Sircar 2014). These tests, therefore, reflect the mechanics of ventilation which make them very suitable markers of changes happening in the lung with different yogic breathing practices. In addition, FVC is also considered to be a marker of cardiorespiratory health and quality of life (Burney et al., 2011).

Bhastrika pranayama has been described as a “vitalizing” pranayama, one which increases the flow of “prana” in the pranic body (Muktibodhananda et al., 1998). Yogic philosophy describes the construct of “Panchakoshas” which conceptualizes human beings to have 5 koshas or sheaths—“annamaya” kosha (physical body or food body), “pranamaya” kosha (pranic body), “manomaya” kosha (mental body), “vijnanamaya” (intuitive body), and“anandamaya” (bliss body, a transcendental realm). Breath is considered as the manifestation of this life force or prana (Muktibodhananda et al., 1984; Feuerstein, 2008). In terms of physiology, Bhastrika pranayama is similar to a process of controlled hyperventilation done in a specific pattern. Hyperventilation increases the activity of the sympathetic nervous system (Alexopoulos et al., 1995; Van De Borne et al., 2000). Studies done on experimental models show that the sympathetic nervous system directly affects the skeletal muscles by modulating blood flow, metabolism, muscle repair, proliferation of muscle stem cells, and as well as transmission across the neuromuscular junction (Benarroch, 2024). It also affects the myelin thickness and myofiber subtype composition. Sympathetic activation has also been documented to produce a certain anabolic and neuroprotective effect on the muscles (Rodrigues et al., 2019). In the context of the present study, this could imply that better skeletal muscle mass and performance of the diaphragm, and the accessory muscles of breathing could contribute to an increase in FVC and PEFR. Sympathetic activation also causes relaxation of the bronchial smooth muscle and consequent dilatation of the tracheobronchial tree (Barrett et al., 2012). This could result in reduced airway resistance and higher airflow rates. On spirometry, this could manifest as an increase in flow rates like PEFR, as found in our study. Mechanically too, forceful exhalations in quick succession strengthen the respiratory muscles allowing them to contract more and accommodate a greater volume of air compared to earlier states. Forceful and deep breathing is also found to recruit previously closed alveoli, thereby increasing the volume of air in the lungs and the diffusion of gases (Singh et al., 2012). Bhastrikapranayama also helps in the removal of secretions from the tracheobronchial tree which clears up the respiratory passages and the alveoli making room for more air (Makwana et al., 1988). All of this also could manifest as an increase in both FVC and PEFR as found in our study.

Nadishodhana pranayama is considered as a balancing pranayama, which causes better sympathovagal homeostasis. The emphasis on slow and deep inhalation and exhalation ensures prolonged and efficient use of the diaphragm and the accessory muscles of breathing. This results in greater filling and better emptying which would result in an improvement in FVC (Anand and Chinna, 1961; Makwana et al., 1988). Another plausible mechanism could be the release of surfactants which improves lung compliance. The more the lung expansion, the more is the surfactant expressed by the pneumocytes (Bijlani and Manjunatha, 2011; Navoday et al., 2015; Pal et al., 2019).

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Conclusion

Our study showed that practicing a vitalizing (Bhastrika) and balancing (Nadishodhana) pranayama together produced a small but significant improvement in the ventilatory functions of the lungs. In other words, the mechanical properties of the respiratory system and chest wall, which govern air movement, are improved through these breathing practices. This research adds new evidence to the scientific literature surrounding the ancient Indian yoga tradition. Our study also showed that devoting just 15–20 minutes of time to these breathing practices per day produced a cumulative benefit. In a fast-paced world, this is an important factor.

Limitations and challenges

Ensuring compliance and consistency in the practice is a big challenge. People usually feel self-motivated once they feel a demonstrable change in the physiological parameters, which could take some time to manifest. We confined our study to 6 weeks. Studies of longer duration would provide a clearer picture of the extent of change.

Acknowledgments

The authors express their sincere gratitude to Swami Rama Himalayan University Jolly Grant, Dehradun for supporting the project. The authors acknowledge the help offered by Mr. Navneet and Ms. Ritu, PhD scholars, Himalayan School of Yoga Sciences, Swami Rama Himalayan University.

Fundings

None.

Conflicts of interests

Nil.

Authors’ contributions

All authors have participated in the conception and execution of the study as well as analysis and interpretation of data. The final version has also been read and approved by all.

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