PHYSIOLOGICAL SCIENCES IN INDIA: FOUNDATIONS AND FRONTIERS
Edited by K.N. Sharma, FNA
RESEARCH ON YOGA
Shirley Tells 1 and R. Nagarathna 2
Vivekananda Kendra Yoga Research Foundation, Bangalore, India
In recent years there has been considerable interest in scientific research on yoga in India and in the West. However, it is heartening as well as interesting that the earliest research on this ancient Indian science began in Lonavala (Maharashtra). The meticulous work which also involved X-ray studies was carried out by Swami Kuvalayananda (Kuvalayananda 1925a,b), who demonstrated intra-visceral pressure changes as well as shifts in the relative positions of the viscera during Kriyas or cleansing procedures. After this, for a while yoga research was focused on investigating physiological potentials and some unusual claims of yogis being able to lower their metabolism (Anand et al. 1961a), to shut off sensory stimuli while meditating (Anand et al. 1961b), and their ability to alter their cardiovascular functions at will (Anand et al. 1961 c, Wenger et al. 1961, Kothari et al. 1973).
In the early 1970s, a new dimension was given to research on yoga when the epoch- making study by Wallace (1970) showed that the practice of Transcendental Meditation brings about a "unique hypo-metabolic physiologic wakeful state" with overall signs of psycho-physiological relaxation. The seventies also witnessed a spate of research work conducted in various laboratories of India primarily directed to study the variety of physiological changes occurring in common man during yogic practices. Detailed experiments on the physiologic effects of diverse practices (e.g. asanas) have been conducted in Lonavala (Bhole 1970). A study from DIPAS (Delhi) showed that six months training in asanas (physical postures), Pranayama (breathing practices), and meditation brought about definite physiological changes in normal volunteers, viz. an increase in ortho-static tolerance and an overall shift in the autonomic equilibrium towards prasyampatho dominance, as was shown during Transcendental Meditation (Selvamurthy et al. 1983). However, more recently, work done at the Department of Neuro-physiology, NIMHANS (Bangalore) has revealed that descriptions of overall effects of yoga practice such as a reduction of sympathetic activity are not to be expected. Different variables such as the pulse, skin resistance and heart rate can be expected to change differently when the same subject practices yoga (Telles & Desiraju 1993). These findings are in accordance with known views of autonomic response and individual specificity (Engel 1960).
Most of the other research on the physiological changes during yogic practices have been confined to specific parameters. The cardiac recovery index (CRI) assessed by the Harvard step test was shown to increase after 2 ½ months of yoga training (Muralidhara & Ranganathan 1982). Six months of yogic asanas were also shown to increase hip and shoulder flexibility in the middle-aged men whereas physical exercises had no such effect (Ray et al. 1983). Nayar et al. (1975) demonstrated improvement in cardio-respiratory functions in NDA cadets trained in yogic practice as compared to those undergoing physical training. The body flexibility and the muscular efficiency improved after six months of yoga training (Ray et al. 1986). The improvement in muscular efficiency was reflected as an increase in endurance time probably due to alternate recruitment of motor units. Besides, yogic practice could result in a significant improvement in physiological responses to acute cold exposure by facilitating the process of non-shivering thermo genesis (Selvamurthy et al 1988). Yogic practices have also been found useful in improving biological markers of ageing. Aroor and co-workers (Aroor et al 1990) reported significant increase in cardiac efficiency index, vital capacity, Creatinine Clearance, decrease in blood glucose and urinary excretion of catecholamines after one month of yogic practices. Reports of energy expenditure and ventilator responses to siddhasana have shown greater minute ventilation, larger tidal volume, higher 02 consumption, greater C02 elimination, and higher heart rate in sitting posture as compared to horizontal-supine and chair-sitting postures (Rai et al. 1994). The results suggest that siddhasana is a mild type of exercise and may have its applications in conditions of low cardio-respiratory reserves particularly in individuals in whom heavy exercises are contra-indicated.
1. Assistant Director of Research, Vivekananda Kendra Yoga Research Foundation,
2. Chief Yoga Therapy Consultant, Vivekananda Kendra Yoga Research Foundation.
No.9, 1st main Appajappa Agrahara, Chamarajpet, Bangalore 560 018.