Experimentally induced emotions, facial muscle activity, and respiratory resistance in asthmatic and non-asthmatic individuals

We studied the effects of emotion induction on total respiratory resistance , and their relationship with cardiac vagal activity and facial muscle acti vity in asthma. Groups of 20 asthmatic and 20 non-asthmatic participants we re exposed to series of happy and depressing pictures or self-referent: Vel ten statements. Facial electromyographic activity over corrugator supercili i, orbicularis oculi, and zygomaticus major regions was recorded during per iods of presentation and imagery of each stimulus. Following each stimulus series, mood, respiratory resistance, ventilation, and cardiac activity inc luding respiratory sinus arrhythmia (RSA) were recorded. Significant increa ses of respiratory resistance were observed in asthmatic patients following depressing stimulation. Resistance increases were positively correlated wi th RSA and heart period. No substantial group differences were found in fac ial response to emotional stimuli. Changes in facial target muscle sites du ring positive stimulation were inversely correlated with RSA following stim ulation. We conclude that respiratory resistance increases in asthmatics fo llowing depressing stimulation are dependent on vagal activity. Greater fac ial muscle activation during emotional stimulation can reduce vagal activat ion, which is consistent with claims in the clinical literature of the bene fits of emotional expression in asthma.