Relationships between trait and respiratory parameters during quiet breathing in normal subjects.

Respiratory patterns are influenced and altered by various emotional changes. In the present study, we investigated how respiratory patterns differ from individual to individual during quiet breathing. We examined the State-Trait Anxiety Inventory and various respiratory parameters in 16 healthy male subjects. Tidal volume was significantly larger and respiratory rate (RR) was significantly higher in both the higher trait (HT) and higher state (HS) anxiety groups compared to the lower trait and lower state anxiety groups. Inspiratory (T I ) and expiratory time (T E ) was significantly shorter in both the HT and HS anxiety groups. There was no significant difference in minute ventilation between these two groups. End-tidal CO2 %, heart rate, and oxygen uptake ([Formula: see text]) also showed no significant differences. V T showed a negative correlation and RR showed a positive correlation with trait scores. T I and T E showed a negative correlation with trait anxiety scores. However, no other respiratory parameter showed any correlation. These results suggest that the respiratory rhythm reflected by RR is affected by the activity generated in the higher center in accordance with the level of trait anxiety during quiet breathing in awake humans.