Objectives: Choice has been linked to both motivation and psychological responses to exercise. This paper investigates participants' psychological responses when they completed an exercise session where there was a high-preference exercise mode as opposed to a low-preference exercise mode. High- and low-preference were established by participants indicating their preferred choice of exercise from three standard modes used for aerobic work.Method: Participants were 20 low-active adults who exercised for 20 min on each mode of exercise (high-preference versus low-preference). Affect, ratings of perceived exertion (RPE) and heart rate (HR) were recorded every 5 min during exercise, and affect and HR were assessed pre-exercise and 5 min post-exercise.Results: Repeated measures analysis of variance revealed condition and time main effects for affect sub-scales and RPE and a time main effect for HR. Affect sub-scales, RPE and HR generally increased over time. RPE, Fatigue and Psychological Distress were higher in the low-preference condition and positive well-being was higher in the high-preference condition.Conclusions: Affect and RPE were influenced by the preferred choice manipulation. Affect was more positive, and RPE lower, in the high-preference versus low-preference condition while work rate remained constant across conditions.