Location: Healthy Body Weight ResearchTitle: Genetic Variations in the Dopamine Reward System Influence Exercise Reinforcement and Tolerance for Exercise Intensity
|FLACK, KYLE - University Of Kentucky|
|PANKEY, CHRISTOPHER - Former ARS Employee|
Submitted to: Behavioural Brain Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2019
Publication Date: 8/9/2019
Citation: Flack, K., Pankey, C., Ufholz, K.E., Roemmich, J.N. 2019. Genetic variations in the dopamine reward system influence exercise reinforcement and tolerance for exercise intensity. Behavioural Brain Research. https://doi.org/10.1016/j.bbr.2019.112148.
Interpretive Summary: This study examined data from two prior studies, to examine the impact of genes on exercise motivation and the ability to tolerate the physical discomfort associated with exercise. Participants’ motivation to be physically active rather than sedentary was measured using a computer-based task and tolerance for exercise discomfort was measured with questionnaires. A small amount of blood was drawn from participants and 23 genes known to be related to physical activity, pain perception or dopamine release were examined. Results indicated a genetic contribution to both greater exercise motivation and greater ability to tolerate exercise discomfort. Such results may be used to tailor exercise programs to certain individuals and facilitate greater exercise behavior among the general population.
Technical Abstract: Background: Exercise is a reinforcing behavior and finding exercise highly reinforcing is a common characteristic of habitual exercisers, especially those that have a greater tolerance for exercise discomfort. Genotypes related to dopamine metabolism moderate the reinforcing value of behaviors, but genetic moderators of exercise reinforcement have not yet been established. Purpose: To determine whether singular nucleotide polymorphisms (SNPs) that moderate central reward pathways and pain neurotransmission are associated with exercise reinforcement, tolerance for exercise discomfort, and usual physical activity. Methods: Men (n=51) and women (n=127) were measured for the reinforcing value of exercise relative to sedentary activities (RRVexercise), minutes of moderate-to-vigorous physical activity (MVPA) and completed the Preference for and Tolerance of the Intensity of Exercise Questionnaire (PRETIQ). Genotyping of 23 SNPs identified to influence central dopamine tone, pain, or physical activity was performed. ANOVA was used to test differences in RRVexercise, tolerance for exercise discomfort, and MVPA among genotype groups. Linear regression analysis controlling for BMI, sex, liking of exercise, was used to further predict the association of genotype on RRVexercise, tolerance for exercise discomfort, and MVPA. Results: Having at least one copy of the G allele for the DRD2/ANKK1 polymorphism (rs1800497) conferred greater RRVexercise. Greater tolerance for exercise intensity was observed among those who were homozygous for the T allele for the CNR1 polymorphism (rs6454672), had at least one copy of the G allele for the GABRG3 polymorphism (rs8036270), or had at least one copy of the T allele for the LPR polymorphism (rs12405556). Homozygous individuals for the T allele at rs6454672 exhibited greater MVPA. Conclusion: There is a genetic contribution to exercise reinforcement and to MVPA. Tolerance for exercise discomfort, which predicts exercise reinforcement, is also associated with polymorphisms that moderate central reward processes, pain neurotransmission, and physical activity.