Objectives: This study determined whether a moderate- or high-dose exercise program increases exercise reinforcement. Increasing the relative reinforcing value of exercise (RRVexercise; i.e., incentive sensitization of exercise) may increase the usual physical activity (PA) participation. Preference and/or tolerance for the intensity of exercise was also assessed.
Design: Sedentary men and women (body mass index, BMI: 25–35 kg/m2) were randomized into parallel exercise training groups expending either 300 (n = 18) or 600 (n = 18) kcal/exercise session, five sessions/week, for 12 weeks.
Methods: The RRVexercise was determined by how much work was performed for exercise relative to a sedentary alternative in a progressive ratio schedule task. Preference and tolerance for exercise intensity were determined by questionnaire.
Results: RRVexercise increased (P \u3c 0.05) in both groups. Exercise reinforcement, defined as the amount of work completed for exercise without taking sedentary activity into account, increased (P \u3c 0.01) in the 600 kcal group only. Preference and tolerance for exercise intensity increased (P \u3c 0.01) in both groups, which predicted increases in RRVexercise.
Conclusion: Expending 300 or 600 kcal, 5 days/week increases RRVexercise, while 600 kcal, 5 days/week may be needed to increase exercise reinforcement
