Effect of Daily Stress on Heart-Rate Variability during Stroop Color Word Task

It is important to care and manage daily stress, even for young healthy individuals. Conventional approach to investigate the effect of mental stress on our body usually utilizes a cognitive task as an induced stressor and compares the response with a resting state. During the process, the effects of daily stress are ignored. We hypothesized that the response to mental stress may differ depending on the daily stress level. As far as our knowledge, the effect of daily stress on cognitive ability and electrophysiological response has not yet been widely investigated. We designed and conducted an experiment to record ECGs while performing a Stroop color word task for 42 young healthy female subjects. We repeated the experiment for two different days with different levels of stress measured by self-report. As a result, we could find significant differences on behavior and heart-rate variability depending on the stress level. These findings may provide a new insight on how to understand the trend of heart-rate variability according to subject's daily stress.