Exercise Genes: Genomic Association With Exercise Reinforcement (ExGenes)

The investigators propose that an individual's genetics are one factor that may be associated with the motivating aspect or attractiveness of exercise and therefore the choice to exercise rather than be sedentary. They propose to study the association of the genomic signatures with the reinforcing (motivating) value of different types of exercise. This has never been investigated and may uncover underlying mechanisms that would help to understand individual differences in exercise motivation. The ultimate impact of this work is a greater number of Americans being physically active, meeting the United States Department of Agriculture (USDA) dietary guidelines for physical activity, and maintaining a healthy body weight. This study will be funded and undertaken at the Grand Forks Human Nutrition Research Center (GFHNRC). The purpose will be to assess genetic underpinnings of the motivating value of resistance and aerobic exercise, and to determine whether the motivating value of aerobic and resistance exercise are associated with usual participation in these modes of exercise.

Subjects will sample and rate their liking of three cardiovascular machines (treadmill, cycle ergometer, elliptical step ergometer) to determine which one will be used during the test.

Subjects will sample and rate their liking of three different resistance training circuits (upper body, lower body, core) to determine which one will be used during the test.

Subjects will rate their liking of three sedentary activities (reading magazines, playing puzzles, completing word games) as an alternative to exercise.

RRV of physical activity will be assessed by evaluating the number of responses (mouse button presses) a subject is willing to complete to gain access to physical activity or a sedentary alternative.

Preference for intense physical activity and tolerance for exercise discomfort will be assessed by self-report questionnaire responses.

Genotypes of 23 small nucleotide polymorphisms (SNPs) previously identified to influence central dopamine release or uptake, reward, or physical activity

SNP genotyping will be performed on 3-5 ml samples of whole blood collected in ethylenediaminetetraacetic acid (EDTA)-containing tubes followed by allelic-discrimination analysis for the amplification and identification of each SNP.

Inclusion Criteria: BMI within 18.5-35.0 kg/m2 Healthy enough to exercise Active or inactive (not exercising at this time) Exclusion Criteria: Taking any drugs that affect energy expenditure (e.g., thyroid, glucose-lowering drugs) Have gained or lost more than 5% of body weight over the past 6 months Use tobacco Pregnant or lactating or plan to become pregnant in the next 6 months Have any health conditions that prevent the individual from safely exercising (e.g., cardiovascular, liver, endocrine, or pulmonary diseases)