DISCUSSION In the present study school children belonging to the alternate nostril breathing (nds), right nostril breathing (sav), and left nostril breathing (cav) groups showed a significant increase in the hand grip strength of both hands at the end of the ten day yoga training camp. The breath awareness (baw) and hand gesture / mudra (mdr) groups showed no significant change. There was no clear lateralization effect, i.e. neither ipsilateral nor contralateral to the nostril of breathing. Both SAV and CAV groups showed a marginally greater increase in left hand scores compared to the right hand (6.5% versus 4.4% and 5.3% versus 4.1%, respectively for sav and cav groups). The nds group showed marginally greater scores for the right hand (6.3 versus 5.0%). The absence of change in the mdr group suggests that practice of the mudras alone did not change the hand grip strength. Also, breath awareness alone did not produce any change. This suggests that the practice of pranayama has a significant effect in increasing hand grip strength, bilaterally, irrespective of (i) the nostril through which the subjects breathe. (ii) maintaining breath awareness, or (iii) the practice of mudras. Previous studies have shown that twelve weeks practice of selected asanas (30 min a day) cause a 21 percent increase in the hand grip strength in normal volunteers (6). The practice of
Table 1: Hand grip strength in kg in five groups at the start (S) and end (E) of the 10-day camp for right (RH) and left (LH) hands. Values are group mean + SEM. pranayama (48 min a day) in addition to physical workouts caused an increase in work rate on a treadmill and reduction in oxygen consumption per unit work, compared to a group which had physical workouts alone (8). Work did not increase blood lactate levels in the 'pranayama' group, which also had significantly lower values at rest. Hence the practice of pranayama made the significant difference, even though both groups were already doing physical workouts. This is similar to the results of the present study, in which the practice of pranayama four times a day in three groups (sav, cav, nds) made a significant difference to hand grip scores, compared to two other groups (baw, mdr), even though all five groups practised yogasanas, pranayama practices excluding the group-specific practices, kriyas, lectures and meditation. The availability of energy and oxidation of glucose is believed to influence the hand grip strength proportionately (9). Hence the pranayama practice may increase hand grip strength by reducing the oxygen requirement. The other important issue is whether any pranayama would cause the change, or whether the result was specific for sav, cav and nds practices. In the study cited above (8), the pranayama practice was not described. In the present study, since all five group practiced non-specific pranayamas and breathing techniques, i.e. sectional breathing, yoga breathing, nadisuddhi, brahmari, sitali, sitkari, sadanta and ujjayi, it appears as though the group specific practices (sav, cav, nds) made the difference. In the traditional texts pranayama practices involving manipulating the nostrils, are supposed to balance and awaken the life energy (10). This may be an explanation for the improved grip strength following sav, cav or nds. However, there is no scientific validation for this. It is also possible that the time spent in specific pranayama practices (27 rounds, four times a day), in addition to an hour a day for the non-specific practices (common to all five groups) was responsible, during the 10 day period. In the earlier cited study (8), subjects practised pranayama for 48 minutes a day, but they were followed up after one and two years. In order to be able to decide whether the effect observed in the present study is related to the duration or type of pranayama practice further comparative studies are required. |