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.

Key words: Bhastrika pranayama, Nadishodhana, Dynamic Lung function, spirometric indices, Yoga