Motivation to Exercise

Study Overview
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Brief Summary
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The purpose of this study is to understand how to make exercise more attractive to people.

Detailed Description
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This investigation will address increased physical activity and will yield empirical evidence to inform developing tools to help individuals make healthy choices regarding physical activity (PA) and maintenance of healthy body weight. Behavioral Choice Theory provides a framework for understanding choices people make and how to shift an individual's choice toward healthier alternatives. The theory holds that choice is based on the relative motivating values of alternatives. One way to shift choice toward a healthier alternative is to increase the relative reinforcing value (RRV), or motivating value, of that alternative. Thus, increasing the RRV of PA behaviors could shift choice towards PA and away from less healthy, sedentary alternatives. Increasing the RRV of PA may allow PA to compete with more reinforcing, sedentary behaviors, resulting in a shift in behavioral choice. This process is termed incentive sensitization, which was originally proposed to explain drug addiction. Incentive Sensitization theory posits that the RRV of a behavior is increased through repeated exposures, which produce neuroadaptations that increase craving of the behavior - after repeated exposures to a stimulus, a 'sensitization' or hypersensitivity to the incentive motivational effects of the stimulus follows. Another factor that influences motivation for a behavior is the development of tolerance to unpleasant aspects of that behavior. Opponent-Process Theory would account for the acquisition of motives where the initial reinforcer may be negative - the affect experienced after repeated exposures is opposite to that experienced during the first few presentations. For exercise, this would include tolerance to any discomfort, pain, fatigue and displeasure and a greater positive post-exercise affective response: the affect experienced during and after exercise has a greater motivational significance in PA participation than knowledge and beliefs regarding health benefits. Therefore, the investigators propose that repeated exposures to PA will produce tolerance to unpleasant aspects while increasing the post-exercise affect. Sensitizing PA reinforcement and increasing discomfort tolerance may be associated with increasing the duration and intensity of daily activity. There are likely to be individual differences in sensitization of PA reinforcement and development of discomfort tolerance. Single-nucleotide polymorphisms (SNPs) that alter dopamine tone in the central dopaminergic reward system and SNPs associated with altered pain perception may contribute to such individual differences. The investigators anticipate that a moderate PA dose (300 kilocalorie [kcal] expenditure) will produce greater incentive sensitization and tolerance than a low dose (150 kcal) and that SNPs related to central dopamine tone and pain perception may contribute to individual differences in incentive sensitization and changes in physical activity after repeated exposures to physical activity.

Official Title
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Motivation to Exercise

Conditions
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Obesity, Physical Activity, Overweight

Intervention / Treatment
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* Other: High Dose Exercise (300 kcal)
* Other: Low Dose Exercise (150 kcal)
* Other: No Exercise (0 kcal)
* Other: Sedentary Option


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI within 19-35 kg/m2 Healthy enough to exercise Sedentary (not regularly engaging in exercise more than once per week) Exclusion Criteria: Taking any medications that affect energy expenditure or eating Have gained or lost more than 10 pounds over the past 3 months Use tobacco Pregnant or lactating or plan to become pregnant in the next 6 months Have any medical conditions that prevent the individual from safely joining in physical activity Have high work-related activity such as construction and farm work

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 49 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: High Dose Exercise vs Sedentary Option<br>Relative Reinforcing Value of high dose exercise (300 kcal expenditure per session) versus sedentary activity will be determined. | Other: High Dose Exercise (300 kcal)<br>* Subjects will participate in 3 physical activity sessions per week expending 300 kcal per session and rate their liking of exercise.<br>Other: Sedentary Option<br>* Subjects will rate their liking of sedentary activities (reading magazines, playing word games, puzzles) as an alternative to exercise.<br>|
| Other: Low Dose Exercise vs Sedentary Option<br>Relative Reinforcing Value of low dose exercise (150 kcal expenditure per session) versus sedentary activity will be determined. | Other: Low Dose Exercise (150 kcal)<br>* Subjects will participate in 3 physical activity sessions per week expending 150 kcal per session and rate their liking of exercise.<br>Other: Sedentary Option<br>* Subjects will rate their liking of sedentary activities (reading magazines, playing word games, puzzles) as an alternative to exercise.<br>|
| Other: No Exercise vs Sedentary Option<br>Relative Reinforcing Value of no exercise (0 kcal expenditure per session) versus sedentary activity will be determined. | Other: No Exercise (0 kcal)<br>* Subjects will participate in 3 sessions per week expending 0 kcal per session and rate their liking of exercise.<br>Other: Sedentary Option<br>* Subjects will rate their liking of sedentary activities (reading magazines, playing word games, puzzles) as an alternative to exercise.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in relative reinforcing value (RRV) of physical activity | 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. | Week 0, Week 6, Week 10 | 
| Changes in preference for intense physical activity and tolerance for exercise discomfort | Changes in preference for intense physical activity and tolerance for exercise discomfort will be assessed by self-report questionnaire responses to the Preference for and Tolerance of the Intensity of Exercise Questionnaire (PRETIE-Q). | Week 0, Week 6, Week 10 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in minutes of physical activity, as assessed by activity tracker | Minutes of physical activity will be assessed by having participants wear an Actigraph accelerometer for 7 days (minimum 10 hours per day) on the right hip. | Week 0, Week 6, Week 10 | 
| Changes in perceived support for physical activity from friends and family members | Changes perceived support for physical activity from friends and family members will be assessed by self-report questionnaire responses to the Social Norms and Support for Exercise Questionnaire. | Week 0, Week 6, Week 10 | 
| Changes in perceptions of how much exercise satisfies autonomy, relatedness, and competence needs | Changes in perceptions of how much exercise satisfies autonomy, relatedness, and competence needs will be assessed by self-report questionnaire responses to the Psychological Need Satisfaction in Exercise Scale. | Week 0, Week 6, Week 10 | 
| Changes in intrinsic, external, interrogated, identified, introjected and amotivation for physical activity | Changes in intrinsic, external, interrogated, identified, introjected and amotivation for physical activity will be assessed by self-report questionnaire responses to the Behavioral Regulation in Exercise, 3rd Edition (BREQ-3). | Week 0, Week 6, Week 10 | 
| Changes in perceived effort expended during exercise | Changes in perceived effort expended during exercise will be assessed by self-report questionnaire responses to the Rating of Perceived Exertion Scale. | Week 0, Week 6, Week 10 | 
| Changes in perceived pain/discomfort during exercise | Changes in perceived pain/discomfort during exercise will be assessed by self-report questionnaire responses to the Muscle Pain Questionnaire. | Week 0, Week 6, Week 10 | 
| Changes in perceived ability to continue exercise long-term | Changes in perceived ability to continue exercise long-term will be assessed by self-report questionnaire responses to the Exercise Self-Efficacy Scale. | Week 0, Week 6, Week 10 | 
| Changes in perceived ability to stick to an exercise routine | Changes in perceived ability to stick to an exercise routine will be assessed by self-report questionnaire responses to the Exercise Confidence Survey. | Week 0, Week 6, Week 10 | 
| Changes in perceived affective responses to exercise | Changes in perceived affective responses (energy, tiredness, tension, calmness) to exercise will be assessed by self-report questionnaire responses to the Activation Deactivation Adjective Check List (ADCL). | Week 0, Week 6, Week 10 | 
| Changes in average daily caloric intake | Changes in average daily calorie intake will be assessed by reporting all foods and beverages consumed over a 3-day period. | Week 0, Week 6, Week 10 |