The influence of body position on autonomic nervous system function.

Five physiological measurements were recorded while 20 males Ss listened to a series of tones in two body positions (horizontal and vertical). Half the Ss were tested in the horizontal position, then raised to a vertical position. The other half were tested vertically first. The results showed body position significantly influenced basal levels for heart rate (HR), finger volume (FV), skin resistance (SR) and blood pressure (BP). In the vertical position, sympathetic arousal was higher than in the horizontal position. In addition, the sequence in which a S was tested influenced physiological activity in the two body positions. It was concluded that both resting levels and pretest activity levels are important variables to consider in research on physiological differences in psychiatric populations.