Applying virtual reality to exercise has revealed mood- and performance-enhancing properties of immersive media. Social–cognitive theory and the Proteus effect suggest that avatar appearance contributes to this relation by eliciting behavioral changes. Attempting to influence exercise parameters without modifying the virtual avatar, the present study investigated the effects of differing visual flow speeds on physiological and perceived effort during aerobic exercise. Eighty-two university students participated in three separate experimental trials. During each trial, a virtual cycling track was presented at one of three velocities (16, 20, 24 km/h) in counterbalanced order, while participants cycled at a moderate intensity for 20 min. Objective and subjective measures of effort and affective states were recorded every five minutes. With increasing visual flow speed, a linear decrease of heart rate, perceived effort, and arousal and a linear increase of valence were expected. Mixed linear model analyses revealed no significant main effect of visual flow speed on any dependent variable. A nonlinear relation between visual flow speed and heart rate was identified through pairwise comparisons between visual flow conditions.