This study analyzed the predictor variables of participants’ intentions to exercise, subjective perception of exercise, and objective exercise behavior. For that it was adopted a cross-sectional design with follow-up measures of exercise behavior that was evaluated for a period of three months. The study included 304 participants (female = 198, 65%) aged between 14 to 73 years (M = 36.11; SD = 13.17) exercising in private fitness centers. We evaluated three sets of variables: personal (age and gender), physical activity (past exercise behavior), and psychological characteristics of participants (including variables from the Theory of Planned Behavior, the Transtheoretical Model, Self-determination Theory, and Emotional and Affective States Theory). The combination of independent variables most strongly predicted intention to exercise (71% of the variance), followed by subjective perceptions of exercise (38%), and last, by exercise behavior (16%). Results implicate the need to accommodate new variables and theoretical approaches to explain exercise behavior.info:eu-repo/semantics/publishedVersio