In this paper, I sought to understand how gratitude activities could improve the biological health and well-being of students and decrease the students’ stress-level. Previous research has found that gratitude increases oxytocin, sleep quality, and activity in the medial prefrontal cortex and anterior cingulate cortex. In my correlational study, I tested the strength of these relationships by examining naturalistic daily changes in their variables longitudinally over a two-week period. I inferred the oxytocin level by measuring my average blood pressure and the frequency of feelings of caring/sympathy each day, rated sleep quality by the sleep score recorded in Fitbit after monitoring the sleep each night, determined prefrontal cortex activity by the score in the PEBL Bivalent Shape Task, and measured gratitude activity by the frequency of the gratitude feelings each day. Data gathered in my correlational study showed no significant correlations of gratitude activity with oxytocin level, prefrontal cortex activity, or sleep quality. The result of this study will serve as guidelines on which substitute methodologies are not effective in correlating the gratitude activity to the well-being of the students.