Impact of prolonged video viewing on physical and mental stress: An analysis of autonomic nervous system activity and salivary stress markers.

In recent years, online lectures and conferences have become widespread, but problems such as stress and adjustment disorders caused by watching long videos have become a problem. Few studies have objectively evaluated the minute changes in stress associated with such prolonged viewing. This study aimed to determine the effects of prolonged video viewing on physical and mental stress. Twenty-six students (10 males and 16 females, aged 21-24) from University A participated in this study. The subjects watched both a high-interest and a low-interest video for 90 minutes each and then subjectively evaluated the video content. Heart rate variability analysis was used to assess heart rate and autonomic nervous system changes during video viewing and saliva samples were collected before, during, and after viewing the videos to measure the concentration of stress markers in the saliva. This study was approved by the Gunma University Medical Ethics Review Committee for Human Subjects. The results of the subjective evaluation showed that scores for concentration, comprehension, and interest were significantly higher, while the fatigue score was lower for the high-interest video than for the low-interest video. Both videos caused a decrease in heart rate and low sympathetic nerve activity, and an increase in parasympathetic nerve activity; however, the changes were more pronounced with the high-interest video. In addition, the differences in subjective scores between the high- and low-interest videos were more pronounced in women, with salivary chromogranin A also showing opposite trends for the two videos. This study demonstrates that watching two different types of videos for extended periods affects autonomic nervous system activity, heart rate, and stress hormones in saliva. Since trends differ depending on the type of video and the participants sex, attention should be paid to the video content and the individual subject when examining stress during video viewing.