Prof. J.P.N. Mishra
A gradual and significant improvement in the respiratory functions of the practitioners who practiced yoga for experimental duration was observed in the present study in terms of PIFR, PEFR, VC, FEV and M W. Naturopathy and yoga helps in inducing positive health, alleviating the symptoms of disease by acting at physical and mental levels. Sathyaprabha et al (2001) studied efficacy of naturopathy and yoga in bronchial asthma and showed the significant improvement in PEFR, VC, FVC, FEV1, FEV/ FVC% MW, ESR and absolute eosinophil count. The results of our study are supported by the findings of this study. The changes in the respiratory functions during these practices are of such a nature that they do not lead to any significant disturbance in the body homeostasis (Shrikrishna, 1985). Joshi et al (1992) have reported that pranayama training improves ventilatory functions in the form of increase in FEV, FEV1 and PEFR. Makwana et al (1988) and Yadav and Das (2001) found a significant increase in FEV, FEV1, and PEFR after yoga training. But most of these studies were small and of short term duration including immediate effect of one minute kapalabhati on respiratory function (Gore et al, 1987), significant increase in vital capacity after three weeks of yoga training (Bhole et al, 1970) and positive effect of Buteyko breathing techniques (BBT) in the management of asthma in 39 patients (Bowler et al, 1998). Telles and Desiraju (1991) have studied oxygen consumption during pranayama type of very slow rate breathing and found that the short kumbhaka pranayamic breathing caused a statistically significant increase (52%) in the oxygen consumption (and metabolic rate). In contrast to the above, the long kumbhaka pranayamic breathing caused a statistically significant lowering (19% of the oxygen consumption (and metabolic rate). Singh et al (1990) studied effect of yoga breathing exercises (pranayama) on airway reactivity in subjects with asthma. After baseline assessment over 1 week, 18 patients with mild asthma practiced slow deep breathing for 15 min twice a day for two consecutive week periods. FEV1, PEFR, symptom score, and inhaler use over the last 3 days of each treatment period were assessed in comparison with the baseline assessment period; all improved more with the PCL exerciser than with the placebo device.
Few other studies conducted by, Madanmohan et al (1983), Rai et al (1982), and Copal-et al (1973) have also reported that pranayama improves cardio-respiratory functions. In a study on 287 college students (both men and women), Birkel and Edgren (2000) found that yoga training produced a significant improvement in vital capacity across all categories of subjects that included smokers, asthmatics as well as those with no lungs disease. Chen et al (1989) have reported by studding relationship between respiratory muscle function and age, sex, and other factors, that inspiratory muscle endurance is greater in physically active men than sedentary men. Murthy et al (1984) observed that pranayama practice lowers rate of respiration, increases FEV1/FVC, increases slow VC, MW, PEFR, expansion of chest, ability to hold breath and reduces bronchial hyperactivity Kumar et al (1985) gave similar results by studding pranayama.
Farrow and Herbert (1982) found an even 40% decline in oxygen consumption at a 50% decline in respiration rate.
Recently Upadhyay (2008) studied the responses of Alternate Nostril Breathing (ANB), the Nadisudhi pranayama, on some cardio-respiratory functions in healthy young adults. The subjects performed ANB exercise (15 minutes every day in the morning) for four weeks. Cardio-respiratory parameters were recorded before and after 4-weeks training period. A significant increment in peak expiratory flow rate (PEFR L/min) and pulse pressure (PP) was noted. Results indicated that regular practice of ANB (Nadisudhi) increases parasympathetic activity.
It may be concluded, from the results obtained, that the long term and regular practice of yoga manifests in overall improvement in respiratory functions. The pathway of mechanism of yoga involves the higher neural centers in the brain. The particular remedial action generated in the cerebral cortex, in terms of thought modulation and pranic balance, is being communicated to the concerned system/organ through the relative center in the brain. The changes observed in the present study might be attributed to such mechanism of action. It may be inferred that whatever changes has been observed following the practice of yoga may be the sum total of various neuromuscular control efforts over the respiratory functions of the subject, because practice of yoga includes modulation in both muscular and neural performances.
Fibers from medulla oblongata (I neurons and E neurons) travel down the spinal cord and synapse with lower motor neurons in the cervical to thoracic regions. From here, nerve fibers travel in the phrenic nerve to the diaphragm and intercostal nerve endings to the intercostal muscles. During quiet breathing impulses transmit to the external intercostal muscles via intercostal nerves and to the diaphragm via the phernic nerve (Tortora, 2006). The improvement in the ventilatory functions may be due to neural changes that send impulses, after getting a stimulus from breathing modulation by pranayama practice, to the inspiratory area in the medulla oblongata. The stimulus for these changes in respiratory centers may also be from input from proprioceptors, which monitor the movements of related joints and muscles. Through these routes after getting impulses form brain centers to neuromuscular centers, the respiratory muscles expands and give space to the lungs for their maximum expansion which may cause an improvement in the pulmonary ventilation capacities (Seeley at el, 2003).
