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

University of British Columbia

Status: Completed

Conditions: Elevated Blood Sugar

Treatments: Behavioral: HIIT; Behavioral: MICT; Behavioral: CHOICE

Study type: Interventional

Funder types: Other

Identifiers

NCT03576924

G-18-0022225

Details and patient eligibility

About

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.

Full description

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.

Enrollment: 77 patients

Sex: All

Ages: 18 to 75 years old

Volunteers: Accepts Healthy Volunteers

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)

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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77 participants in 3 patient groups

MICT

Active Comparator group

Description:

Continuous exercise for 30 minutes per session at 60-70% of heart rate max for five times per week, consistent with physical activity guidelines that advocate 150 minutes per week of moderate activity.

Treatment:

Behavioral: MICT

HIIT

Active Comparator group

Description:

Five repeated vigorous intervals of 1-min duration at 80-90% of heart rate max interspersed with 1-min recovery periods; 3-min warm-up and 2-min cool-down, making the total session duration 15 minutes for five times/week, equated to match the guidelines of 75 min of vigorous exercise per week.

Treatment:

Behavioral: HIIT

CHOICE

Experimental group

Description:

Participants will be introduced to HIIT and MICT during sessions 1 and 2 of the 4-week intervention in a counterbalanced randomized order, and will thereafter self-select one of the two exercise types for remaining sessions. Exercise will be matched to the parallel imposed conditions.

Treatment:

Behavioral: CHOICE