Respiratory characteristics and the effects of regulated breathing on resting psychophysiology

The present study investigated the influence of sex and body position on respiratory characteristics and the effects of thoracic, abdominal and paced breathing, and relaxation training on psychological and physiological indices of arousal. Two separate experiments were conducted, each using equal numbers of male and female subjects. The psychological measures of arousal used were: the Taylor Manifest Anxiety Scale, a self-report measure of arousal, and Time Estimation. Physiological data collected included: Skin Conductance, Heart Rate, Respiratory Rate, thoracic-abdominal index and the inspiration/expiration ratio. Respiratory characteristics were measured using mercury-in-rubber strain gauges. In Experiment 1 the respiratory patterns of 28 subjects were assessed in two body positions: sitting and supine. Subjects were divided according to sex, and allocated randomly to either the sitting-supine order, or the supine-sitting order. In this way four experimental groups were formed. The differences in respiratory patterns, psychological measures, and physiological indices could, therefore, be attributed to either: sex, body position, or the order in which assessment occurred. Experiment 1 revealed that in the sitting position female subjects breathe relatively more thoracically than do male subjects. In the supine position both sexes breathe predominantly abdominally. Thoracic I/E ratios were found to be higher in male subjects than in female subjects and both thoracic and abdominal I/E ratios were effected by •body position and order of position. In the supine position subjects displayed longer inspiratory times than in the sitting position. Similarly, in the sitting-supine order subjects displayed longer inspiratory times than in the supine-sitting order. It was shown that predominantly abdominal breathing was associated with longer thoracic and abdominal inspirations than was thoracic breathing. • Experiment 2 used 48 subjects who were also divided according to sex and randomly allocated to one of four treatment conditions: thoracic, abdominal or paced breathing, or relaxation training. In this experiment subjects were assessed only in the sitting position. Thoracic and abdominal training was accomplished with the aid of visual and auditory feedback procedures. Subjects in the paced breathing treatment were required to inhale and exhale as indicated by the sweep of an analogue meter indicator. Relaxation training required subjects to perform tape-recorded relaxation exercises. Subjects in the paced breathing condition served as attention controls, whilst the subjects in the relaxation training condition served as an arousal control group. Experiment 2 revealed that training subjects to breathe thoracically or abdominally failed to produce consistent changes in the indices of arousal. Both male and female subjects reported feeling less aroused following relaxation training. Time Estimation and the physiological indices failed to parallel the self-report data. The present results are discussed in respect to current respiratory literature and major methodological issues were identified for future research.