Inducing incentive sensitization of exercise reinforcement among adults who do not regularly exercise-A randomized controlled trial

Authors: Flack, Kyle; Ufholz, Kelsey; JOHNSON, LUANN - University Of North Dakota; Roemmich, James

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/17/2019
Publication Date: 5/7/2019
Citation: Flack, K.D., Ufholz, K.E., Johnson, L., Roemmich, J.N. 2019. Inducing incentive sensitization of exercise reinforcement among adults who do not regularly exercise-A randomized controlled trial. PLoS One. https://doi.org/10.1371/journal.pone.0216355.
DOI: https://doi.org/10.1371/journal.pone.0216355

Interpretive Summary: Most people do not get the recommended amount of physical activity and find it difficult to establish physical activity as a habit. The motivating value of exercise predicts how much physical activity people usually do. Repeatedly engaging in exercise may be one way to increase the motivating value of exercise. This study determined whether repeated exposures to exercise increases exercise motivation and found that the motivating value of exercise increased when expending150 kcal/day in exercise, 3 days/week for 10 weeks. This study also found that those people who increased their tolerance for exercise discomfort were the people who increased their motivating value of exercise. This study provides initial evidence that exercise motivation can increase in sedentary adults and that developing tolerance to exercise discomfort may promote increases in exercise motivation.

Technical Abstract: Introduction: The majority of Americans do not meet physical activity recommendations and find it difficult to establish physical activity as a habit. The reinforcing value of exercise predicts usual exercise participation. Repeated exposures to exercise may be one way of increasing the reinforcing value of exercise (incentive sensitization), but it is not yet known whether incentive sensitization occurs for exercise reinforcement or what factors may be associated with incentive sensitization of exercise reinforcement. Thus, the purpose was to determine whether repeated exposures to exercise increases exercise reinforcement, predictors of reinforcement change, and whether incentive sensitization of exercise reinforcement results in greater usual physical activity. Methods: 104 sedentary men and women were randomized into exercise training groups expending either 150 or 300 kcal per exercise session 3 sessions/week, for 6 weeks or a non-exercise control group. The reinforcing value of exercise and the preference and tolerance for exercise intensity discomfort, and usual physical activity were determined pre- and-post training and after a 4-week follow-up where participants were not required to exercise. Results: The reinforcing value of exercise increased from baseline to post 4-week follow-up in the 150 kcal group and increases in the tolerance for exercise intensity discomfort was associated with the incentive sensitization of exercise reinforcement. Sedentary time decreased from baseline to post-training while light activity increased from baseline to post-training and baseline to follow-up. Conclusion: This study provides initial evidence that incentive sensitization of exercise reinforcement can occur in sedentary adults. Developing tolerance to exercise discomfort may promote incentive sensitization of exercise reinforcement.