"Sitting is the new smoking". This phrase has been repeated in news articles, TED talks, and even journal articles in an effort to draw a comparison between the degree to which excessive sitting and smoking negatively impact health, and subsequently persuade people to reduce their sitting time. While evidence detailing the negative effects of sitting is increasing, research on how to persuade people to reduce sitting time is severely lacking. To address this gap, this study investigated whether a match or mismatch between message type (affective/cognitive) and structural and meta-cognitive attitude bases (AB; affective/cognitive) would yield greater change in attitudes towards breaks from sitting at home and at work. Participants' (n=291) overall attitudes towards breaks, and affective and cognitive structural and meta-cognitive AB were assessed before and after participants were randomly assigned to view the cognitive or affective message. Hierarchical regressions that included message type, AB (structural or meta-cognitive), and their interaction as predictors of overall attitudes (home and work) were conducted. Results revealed a relative matching effect for attitudes (home): among participants with affectively-based attitudes, those who saw a matching message showed greater attitude change than those who saw a mismatching message (p<0.05); however, among participants with cognitively-based attitudes, attitude change did not differ by message (p>0.05). For attitudes (work), none of the predictors were significant (p>0.05). These patterns of results were equivalent for structural and meta-cognitive AB. In conclusion, this study partially supports relative matching effects and indicates that matching/mismatching effects may not be uniform across contexts.