A comparison of somatic relaxation and EEG activity in classical progressive relaxation and transcendental meditation.

Oxygen consumption, electroencephalogram (EEG), and four other measures of somatic relaxation were monitored in groups of long-term practitioners of classical Jacobson's progressive relaxation (PR) and Transcendental Meditation (TM) and also in a group of novice PR trainees. All subjects (1) practiced relaxation or meditation (treatment), (2) sat with eyes closed (EC control), and (3) read from a travel book during two identical sessions on different days. EEG findings indicated that all three groups remained primarily awake during treatment and EC control and that several subjects in each group displayed rare theta (5-7 Hz) waveforms. All three groups demonstrated similar decrements in somatic activity during treatment and EC control which were generally of small magnitude (e. g., 2-5% in oxygen consumption). These results supported the "relaxation response" model for state changes in somatic relaxation for techniques practiced under low levels of stress but not the claim that the relaxation response produced a hypometabolic state. Despite similar state effects, the long-term PR group manifested lower levels of somatic activity across all conditions compared to both novice PR and long-term TM groups. We concluded that PR causes a generalized trait of somatic relaxation which is manifested in a variety of settings and situations. Two likely explanations for this trait were discussed: (1) PR practitioners are taught to generalize relaxation to daily activities, and/or (2) according to a "multiprocess model," PR is a "somatic technique," which should produce greater somatic relaxation than does TM, a "cognitive technique." Further research is required to elucidate these possibilities.