All subjects had been practising the Ujjayi pranayama with different ratios of the phase durations of the respiratory cycle. In the typical Ujjayi pranayama 3,4 the respiratory rate is markedly reduced volitionally and each cycle includes successively (i) the phase of inhalation while the glottis is kept partially closed; (ii) the phase of Kumbhak or holding of breath (retention of the inhaled air) during which the glottis is fully closed, and (iii) the phase of a steady exhalation. There may also be a phase of end-expiration Kumbhak or breath-holding in exhaled state, before beginning the next cycle. The cycles were repeated regularly while keeping respective durations of the phases similar in all the cycles of the pranayamic breathing. In typical ratio, the expiration phase is twice that of inspiration while the duration of Kumbhak in end of inspiration is twice that of expiration phase, i.e., 1:4:2 for inspiration: hold: expiration. However, different types of Pranayama differ widely in the ratios of the phase durations. The Kumbhak is to be done in ease and not to be prolonged as in breath-holding for breaking point test. During pranayama, the subject is required to become aware of sensations of passage of air through nasal passages and of filling up of lungs. The entire process of breathing is to be executed without stress and strain, under conscious control, maintaining the ratio of phase durations of each cycle of respiration, carrying on rhythmically, steadily and without jerking movements. In the end-inspiration Kumbhak phase, the perineal muscles are held in contraction, and chin lowered on to the manubrium of sternum (mulabandha, and jalandara bandha). In the end- expiration Kumbhak phase, the abdomen is drawn inwards and backwards with diaphragm in raised position (uddiyan bandha).

Since the duration of the inspiratory Kumbhak is known to be an all-important variable of the Ujjayi Pranayama, we have categorised the ten subjects into two groups of five each, viz., long and short Kumbhak types. In the long Kumbhak group (LK), the Kumbhak (in inspiration) phase duration was 50.4±6.6 per cent of the total duration of respiratory cycle. In the short Kumbhak group (SK) the Kumbhak phase was only about 22.2 ± 10.6 percent of the total cycle duration. The inspiration-Kumbhak-expiration duration’s ratio was about 1:4:2 in the long Kumbhak group, and about 1:1 (or less):1 in the short, Kumbhak group. Three subjects in each group also had the end- expiration Kumbhak. However, there were no differences in other respects, i.e., in the base-line values of the two groups of subjects. Their average ages were not significantly different (Student’s ‘t’ test), the values being 45.2 ± 7.4 years for the SK group and 38.4 ± 13.9 years for the LK group. Besides, the pre-pranayamic base-line values of pulmonary ventilation were not different, the value of the SK group was 15.0±5.8 1/min BTPS and of the LK group was 10.3 ± 2.5 l/min. BTPS (Table 1). The base-line oxygen consumption also, of the two groups was not different (Student’s ‘t’ test), the average values being 269.6 ± 127 ml/min STPD for the SK group and 320.8±96.7 ml/min STPD for the LK group (Table II).