Social pressures focusing on health and physical attractiveness have been used to promote exercise among women (Prichard & Tiggemann, 2008). However, research has shown that motives driven by external sources result in decreased exercise participation (Deci & Ryan, 1985). The current study examined differences in motivation, self-efficacy, and mood between 64 exercise adherent and non-adherent women over four weeks. Women who were non-adherent to their exercise goals were more likely to report external motives, specifically body and health related motives. At the initial measurement, adherents reported significantly lower self-efficacy, positive affect, and life satisfaction compared to non-adherents. However, after the four weeks, adherents’ self-reports indicated a significant increase in these variables compared to no change in non-adherents’ self-reports.