DISCUSSION
The most important finding of this study on the effects of Brahmakumaris Raja yoga meditation was a small (but consistent) increase in the heart rate during meditation, compared to the preceding period, as well as compared to the non-rneditation period. In contrast, changes in respiratory rate, finger plethysmogram amplitude and SR were fewer and often in opposite directions for the subjects practising the same meditation. However, they were consistent during repeat sessions of a subject. These individual differences did not seem to be correlated with differences in age, duration of meditation experience, or commitment to meditation. Individual differences in autonomic response specificity have been known for a long time. Detailed descriptions have shown that autonomic responses are a function of both the evoking stimulus (stimulus-response specificity) and of the responding individual (individual response specifity (Engel, 1960). It is interesting to speculate that the contradictory reports on Transcendental Meditation (TM), Zen, and Tantric yoga, described in the Introduction as either "activating" or "relaxing", may in fact be due to differences in the individual response patterns.

Table II : Changes in heart rate, paimar GSR, finger plethysmogram amplitude and respiratory rate based on individual level analysis I, increase; D, decrease; M, Meditation period; Pre-M, period preceding meditation; NM, nonmeditation period; pre-NM, period preceding non-mediation period.
 

Holmes (1984) commented that no studies showed consistent differences between resting and meditating subjects in heart rate, electrodermal activity, respiratory rate and other similar variables. However, he stated that in 4 out of 16 experiments, meditating subjects showed greater increases in heart rate than did resting subjects, and none showed decreases. In this study also, the most consistent change was an increase in heart rate during the practice of Brahmakumaris Raja yoga meditation which was suggestive of cardiosympathetic activation, and a possible sign of psychophysiological arousal. This finding can be correlated with the fact that BK meditation requires intense involvement and concentration. The changes in the other variables (though often consistent for an individual) did not reveal any group pattern.

These results suggest that use of some autonomic and respiratory variables (e.g., heart rate) may reveal group effects of meditation, whereas other variables can alter in an individualistic way. Hence, a single model of meditation producing either overall relaxation or overall activation is probably inadequate.