Power of Choice on Autonomy, Motivation, Exercise Adherence, and Cardiorespiratory Fitness

People with elevated blood sugar levels are at increased risk of developing chronic medical conditions such as obesity, type 2 diabetes, and cardiovascular disease. Improving cardiorespiratory fitness (CRF) in adults with elevated blood sugar levels is important for preventing the onset of such medical conditions. The primary aim of this study is to determine whether providing a choice between two different types of exercise in a diabetes prevention intervention improves perceived autonomy, exercise motivation, physical activity behavior, and subsequently CRF to a greater extent than imposed exercise among adults with elevated blood sugar.

This trial has been informed by self-determination theory. The theory states that individuals who choose their own activities report increased autonomy and internal reasons/motivations to change a behavior as opposed to external reasons (to satisfy another person's suggestions). Perceived autonomy support and internal motivation for performing a behavior are linked with improved long-term adherence to the behavior change, which subsequently leads to physiological adaptations such as an increase in CRF.

The primary outcome of this study is participants' perceived autonomy support after a 4-week diabetes prevention program. The secondary outcomes are 1) changes in exercise-related motivation from baseline to immediately post-intervention and 6-months post-intervention, 2) physical activity behavior 6-months post-intervention while controlling for baseline values, and 3) CRF 6-months post-intervention while controlling for baseline values. Seventy-seven low-active adults between 18-75 years of age with elevated blood sugar levels (HbA1c between 5.7%-6.4% or American Diabetes Association risk assessment \>5) have been randomized to a 4-week supervised intervention involving behavioral counseling and one of three exercise conditions: 1) imposed high-intensity interval training (HIIT; n=26); 2) imposed moderate-intensity continuous training (MICT; n=26), or 3) choice between MICT or HIIT (CHOICE; n=24). It is hypothesized that when compared to HIIT and MICT, the CHOICE condition will have greater perceived autonomy support immediately after the 4-week intervention, display more internal motivation immediately after the 4-week intervention, and show greater improvements in physical activity adherence and CRF 6-months post-intervention. This proposed trial will provide theory- and evidence-based information whether providing choice for engaging in HIIT or MICT is associated with greater improvements in perceived autonomy support, motivation regulation, physical activity behavior, and CRF.

Eligibility Criteria:
Inclusion Criteria:

* BMI 22-45 kg/m2;
* HbA1c score indicative of elevated blood sugar (5.7-6.4%);
* Blood pressure of \<160/99 mm Hg assessed according to Canadian Hypertension Education Program guidelines;
* Without diagnosed diabetes;
* No prior history of cardiovascular disease;
* Not on hormone replacement therapy;
* Not on beta-blockers;
* Cardiovascular medications (e.g., statins) will be allowed if patients are on stable therapy (6 months on same dose)

Exclusion Criteria:

* Taking glucose-lowering medications (i.e. metformin);
* Any explicit contraindications to exercise (e.g., musculoskeletal injury)