Anxiety and respiratory patterns: their relationship during mental stress and physical load.

In the present study we investigated the effect of mental stress on respiration using unpleasant sounds. To compare the center output of each stimuli, subjects took part in one session divided into two phases: a mental stress test and a physical loading test. The purpose of this study was not only to investigate ventilatory response in emotions caused by mental stress and physical load, but also to determine the relationship between respiratory pattern and personality. Ten normal subjects were measured for VE (minute ventilation), VT (tidal volume), RR (respiratory rate), Vo2 (O2 consumption), Vco2 (CO2 production) and FETco2 (end-tidal CO2 concentration) on a breath-by-breath basis; the subjects were given Spielberger's State Trait Anxiety Inventory (STAI) before beginning this experiment. Unpleasant emotions caused by mental stress altered the breathing pattern. VE increase was achieved by the combination of VT and RR disregarding the subjects' personality. However, subjects with high anxiety RR increased more than VT resulting in a positive correlation between the trait anxiety score and RR. We found that a dominant RR increase was observed not only in the mental stress test but also in the physical loading test. In the physical load, there was a positive correlation between the state anxiety score and RR. These results indicate that respiratory patterns are related to personality anxiety. These findings may provide important evidence relating respiratory function to psychological aspects.