Response of the autonomic nervous system to emotional email on a smartphone

The objective of this research was to evaluate autonomic nervous function by photoplethysmography (PS) during emotional stimuli delivered via a smartphone. The mental and physical status of 24 healthy subjects were assessed using The Cornell Medical Index (CMI), The State Trait Anxiety Inventory (STAI), and The Stress Check Inventory (SCI). The subjects were divided into two groups, those who were psychosomatically stable and unstable. PS was measured during emotional (relaxed, pleasant, and unpleasant) audio-visual stimuli and in response to emotional written stimuli (pleasant and unpleasant stimuli) on a smartphone. PS pulse wave amplitude and length were evaluated. The mean pulse wave amplitudes among stimuli, between “task” (during stimuli) and “recall” (after stimuli), and between groups were compared. Parasympathetic nerve activity in peripheral and central areas was higher during recall than during task of emotional audio-visual stimuli in both groups. In the psychosomatically stable group, peripheral sympathetic nerve activity during recall of emotional written stimuli was higher than during task. In both groups, there were no differences between task and recall in central areas of the body. These events suggest that receiving an email message could activate the sympathetic nerve even after replying to the message and while waiting for a response.