Changes in respiration during emotional stress

In this work, we analyze changes in respiration during emotional stress induced by a modification of the Trier Social Stress Test. The following stages in the test were analyzed: the pre-relaxing stage, the story telling stage, the anticipation of stress and the video exposition stage. Respiration signal is recorded during the whole test using a thoracic band. Power spectral density (PSD) of respiration is computed in running windows using a modification of Welch periodogram in which sufficiently peaked spectra are averaged. Then, respiratory frequency (F_R) is estimated from the “peaked-conditioned” averaged spectra. Results show that respiratory rate is significantly (p <; 0.05 according to the Friedman test) higher, while a measure of spectral peakness and the percentage of PSD used to compute (F_R) is lower during stress stages than during relax. These results suggest that the respiration-related parameters have potential discrimination power for stress level assessment.