This study will examine changes in brain and physical health in adults with type 2 diabetes who are initiating incretin-mimetic therapy (e.g., Ozempic, Mounjaro), and determine whether adding structured exercise provides additional benefits. Participants will be randomized to receive incretin-mimetic therapy alone or incretin-mimetic therapy plus a structured exercise program for 24 weeks. If the participant is randomly assigned to the incretin-based therapy alone group, they will have the opportunity to complete the same structured exercise program after the 24-week study period is complete. Brain health will be assessed through cognitive performance, mental health, and brain-mediated appetite regulation. The study will also assess gut microbiota and motor-cortex neuroplasticity as potential factors associated with changes in brain health, as well as glucose regulation, body composition, physical function, and cardiorespiratory fitness. Assessments will be completed at baseline, 8 weeks, and 24 weeks. Findings will help determine how incretin-mimetic therapy and exercise can be integrated to support brain and physical health in adults with type 2 diabetes.
Type 2 diabetes (T2D) is associated with alterations in cognitive function, mental health, and the regulation of appetite and food intake. Incretin-mimetic therapies are increasingly used in the management of T2D and improve glycemic control while reducing appetite and body mass. However, their effects on brain health remain poorly understood. In addition, body mass loss during incretin-mimetic therapy can include loss of lean tissue, which may have implications for metabolic health and physical function. Exercise is a cornerstone of T2D management and has beneficial effects on glycemic control, body composition, physical function, cognitive function, and mental health. Whether structured exercise provides additional brain-health benefits during incretin-mimetic therapy while helping to preserve lean tissue and physical function remains unclear. The primary objective of this randomized controlled trial is to characterize changes in brain health during incretin-mimetic therapy and determine whether the addition of structured exercise provides additional benefit. Brain health will be considered across three complementary domains: cognitive performance, mental health, and brain-mediated appetite regulation. The study will also examine changes in body composition and metabolic and physical health to determine whether exercise helps preserve lean tissue and physical function during incretin-mimetic therapy. A secondary objective is to investigate the microbiota-gut-brain axis (MGBA) and motor-cortex neuroplasticity as potential mechanistic correlates of brain-health responses. The MGBA represents bidirectional communication between the gut and brain and may influence cognitive and mental health as well as homeostatic and hedonic regulation of food intake. Gut microbial communities will be characterized using 16S rRNA gene sequencing and bioinformatics to examine changes in microbial diversity and composition. Motor-cortex neuroplasticity will be assessed using transcranial magnetic stimulation (TMS). A standardized stimulation protocol will be used to induce changes in motor-cortex excitability, with changes in motor-evoked responses used to quantify the neuroplastic response. These measures will be used to investigate whether changes in motor-cortex neuroplasticity are associated with changes in brain-health outcomes. Together, the study will examine the complementary effects of pharmacological and exercise-based approaches to T2D management and investigate biological factors that may contribute to brain-health responses during treatment.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
110
A 24-week individualized exercise program consisting of three exercise sessions per week. The program will include resistance and aerobic exercise based on Canadian physical activity guidelines, with exercise selection and intensity adjusted to individual abilities and fitness levels. Two sessions per week will be supervised at the University of Regina and one session per week will be completed independently. Each session will last approximately 60-90 minutes. Participants will also receive guidance on adequate protein intake.
Centre for Kinesiology
Regina, Saskatchewan, Canada
Change in insulin resistance (HOMA-IR)
Insulin resistance will be estimated using the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), calculated from fasting glucose and fasting insulin concentrations. Higher HOMA-IR values indicate greater insulin resistance. The primary outcome will be the between-group difference in change in HOMA-IR from baseline to 24 weeks.
Time frame: Baseline, 8 weeks, and 24 weeks
Change in Eating Patterns and Behaviours
Eating patterns and behaviours will be assessed using validated questionnaires examining dietary quality, eating behaviours, appetite, and food cravings. Questionnaire scores will be calculated according to established scoring procedures, with changes assessed over the 24-week intervention.
Time frame: Baseline, 8 weeks, and 24 weeks
Change in cardiovascular health
Resting heart rate variability will be assessed from beat-to-beat cardiac recordings. Heart rate variability will be quantified using prespecified time-domain measures of variation in successive heartbeats. Arterial stiffness will be assessed using pulse wave velocity (PWV), which measures the speed at which the arterial pressure wave travels between two arterial sites. PWV will be expressed in metres per second (m/s), with higher values indicating greater arterial stiffness.
Time frame: Baseline, 8 weeks, and 24 weeks
Change in body composition
Fat- and fat free mass will be assessed using air-displacement plethysmography (BodPod) and expressed in kilograms (kg).
Time frame: Baseline, 8 weeks, and 24 weeks
Change in physical function
Maximal isometric handgrip strength will be assessed using a handgrip dynamometer. The highest force produced during standardized maximal handgrip attempts will be recorded. Lower-body physical function will be assessed using the 30-second sit-to-stand test. Participants will be instructed to complete as many full sit-to-stand repetitions as possible in 30 seconds. Performance will be expressed as the total number of successfully completed repetitions.
Time frame: Baseline, 8 weeks, and 24 weeks
Change in aerobic fitness
Cardiorespiratory fitness will be assessed during a graded exercise test to volitional exhaustion. Peak oxygen uptake (VO₂peak) will be determined from expired respiratory gases and expressed relative to body mass as mL·kg-¹·min-¹. Higher values indicate greater cardiorespiratory fitness.
Time frame: Baseline, 8 weeks, and 24 weeks
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