Prior research has demonstrated that inducing positive expectations of exercise (e.g., that exercise can make people feel better mentally or improve mood) can lead to greater self-reported exercise intentions and behavior. We expanded upon these findings by making a distinction between affect that is experienced mentally (e.g., feel better mentally) versus physically (e.g., bodies feel better) and affect high (e.g., energized) versus low (e.g., calm) in arousal. We examined whether messages that described different types of affective benefits led to greater intentions to exercise, compared to information about health benefits (the control conditions), and further hypothesized that affect experienced mentally versus physically would lead to higher intentions. Participants were 323 adults recruited online through Amazon’s Mechanical Turk. Participants were randomly assigned to one of six conditions in a 3 (expectation: positive affect low arousal vs. positive affect high arousal vs. health benefits) x 2 (type of benefit: mental vs. physical) design. Contrary to our hypotheses, we did not find any differences in intentions to exercise across groups. We did find that participants in the physical benefit conditions reported lower expected fatigue after exercising than the mental benefit conditions. The main effects and interactions on other outcomes of interest were nonsignificant. The null results may have occurred if our manipulation was not strong enough and participants were not sufficiently engaged due to the online nature of the study. It is also possible that these distinctions between affect do not actually influence intentions to exercise.