Effects of a single message exposure on exercise motivation and behavior among adults aged 30-45

Promoting intrinsic affective exercise benefits may facilitate autonomous motivation and exercise behavior. However, most media messages primarily emphasize extrinsic weight and health-related benefits. This study examined whether altering exercise messages would influence individuals' exercise motivation and behavior. Using a 2 x 2 factorial design, message frames were manipulated on the following dimensions: Intrinsic/Extrinsic exercise goal and Easy/Hard exercise routine. A representative sample of adults aged 30-45 (N = 505) completed measures of leisure-time exercise and motivation and then were randomly assigned to view one of the four messages or a control message. Immediately after viewing the message, participants indicated their primary exercise goal. One week later, they completed the exercise and motivation measures again. An ANCOVA revealed no between-group differences in motivation or exercise behavior. Relative to the extrinsic and control conditions, participants in the intrinsic message conditions were more likely to identify an effective primary exercise goal immediately after viewing the message. Overall, a single message exposure did not significantly affect individuals' exercise motivation or behavior in this sample. Future studies should consider honing optimal message content, assessing message understanding and determining the minimum dose of message exposure needed for a meaningful impact.