Researchers have been slow to acknowledge the salient role communication can play in motivating people to adopt more healthy lifestyles. Because persuasive messages increase awareness and can increase health promoting behaviors, it is important to determine the most effective health promoting messages in various health contexts. Thus, the primary goal of this study was to test a method of developing messages that enhance health behaviors, specifically exercise. An experimental design was used to test two research questions and one hypothesis. Data were collected at three time periods; subjects were college students in an introductory communications studies course. Results indicated the importance of communication in health promotion. Messages geared to subjects' stage of exercise were effective. In particular, the contemplation message and the relapse message significantly improved contemplators' and relapsers' stage of exercise, respectively. Messages should be developed that are framed toward peoples' stage of behavior change. The Stages of Change Model (Proshaska and DiClemente, 1983, 1986) was an effective audience analysis tool in this health promotion study. (Contains six tables of data and 58 references; sample questionnaires and forms are appended.) (Author/CR)