The purpose of this study was to investigate how stress affects cortisol levels and memory performance, and whether it affects them differently for those who exercise more. Participants first learned a list of items. The next day, they were placed in two groups: The control group (recognition memory test given before the Trier Social Stress Test) and Stressor Group (recognition memory test given after the Trier Social Stress Test). The impact of the stressor was measured via samples of cortisol levels taken during various points during the course of the study. I am most interested in analyzing the change in concentration from sample 1 to sample 2, as sample 2 was taken after the exposure to the stressor. This analysis will help us determine if participants were convincingly stressed. Regarding memory performance, it was hypothesized that participants who exercised more would respond better to the stressor, and therefore perform better on the memory test compared to those who didn’t exercise as much. The results and their relevance to the general college student population will be discussed.