COMPONENT ANALYSIS OF TASK-RELATED RESPIRATORY PATTERNS

The pattern of breathing, determined by time, volumetric and respirato ry shape parameters was examined in male students subjected to mental arithmetic tasks, sustained attention tasks, a relaxation task and fou r levels of graded exercise. Also, the relationships among the respira tory time parameters were determined by performing a factor analysis o n a pooled matrix containing the parameter correlations across all exp erimental conditions. Relative to baseline, the experimental tasks ind uced rather distinct breathing patterns. During exercise the breathing curves resembled a triangular shape which was caused by a decrease in total breath duration coupled to an increase in both the depth of bre athing and the inspiratory duty cycle time. For both the sustained att ention and mental arithmetic conditions there was a slight decrease in the depth of breathing and a more pronounced decrease in inspiration time. However, during mental arithmetic the decrease in inspiration wa s linked to an increase in expiration duration, exhibiting a breathing curve that resembled a 'saw tooth'. In contrast, the attention tasks induced a slight decrease in expiration duration showing a sinusoidal breathing curve which was more similar to the baseline and relaxation breathing pattern. The factor analysis revealed two respiratory factor s: a time factor reflecting inspiration, expiration and total cycle du ration and a factor related to the inspiratory duty cycle time. We con clude that analysis of breathing patterns with components other than r ate and depth of breathing is a potentially useful research tool.