Feasibility of Aerobic Exercise With Blood Flow Restriction Training in People Living With Type 2 Diabetes

Testing the Feasibility of Blood Flow Restriction Training to Enhance the Health Benefits of Exercise in Individuals With Type 2 Diabetes: a Pilot Randomized Controlled Trial

The goal of this trial is to learn if blood flow restriction training with treadmill walking is possible for individuals living with type 2 diabetes. It will also learn about how the blood flow restriction with treadmill walking could improve health.

The main questions it aims to answer are:

Is 6 weeks of treadmill walking with blood flow restriction reasonable for people with type 2 diabetes to perform? Does treadmill walking with blood flow restriction training help manage type 2 diabetes better than just treadmill walking?

Researchers will compare treadmill walking with blood flow restriction to treadmill walking without blood flow restriction to see if blood flow restriction works to manage type 2 diabetes based on fitness and blood sugar levels.

Participants will:

Perform treadmill walking with or without blood flow restriction for 96 minutes a week for 6 weeks.

Visit the lab before and after the exercise for tests and questionnaires.

Individuals with type 2 diabetes (T2D) display reduced cardiorespiratory fitness, which is a strong predictor of premature mortality and T2D-related complications. Aerobic training (AT) enhances cardiorespiratory fitness and is considered a cornerstone in the management and treatment of T2D. Emerging data suggest that AT combined with blood flow restriction (AT+BFR) training, could potentially enhance cardiorespiratory fitness faster than typical AT in healthy individuals. However, the feasibility of AT+BFR in individuals with T2D and its impact on cardiorespiratory fitness have yet to be determined.

Therefore, the primary objective of this study is to test the feasibility of a 6-week AT+BFR training intervention in individuals with T2D. The secondary objective is to establish preliminary effect sizes for the efficacy of AT+BFR training in individuals with T2D compared to the standard care AT (AT- stdCare).

Methods: This study is a single-blind (investigator & statistical analyst), multi-site, randomized controlled pilot trial of a novel AT+BFR training intervention for individuals living with T2D, which has been informed by patients with lived experience. Participants will be randomized 1:1 using variable permuted block sizes (stratified by sex and site) into 1) AT+BFR or 2) AT-stdCare groups with outcome measures assessed at baseline and 6 weeks.

Population: In 3 sites across Canada, 60 (n=20 per site) individuals living with T2D (5.7% < HbA1c < 9.0%) aged 19-64 years, not meeting the physical activity guidelines (150 mins moderate-vigorous physical activity per week) will be recruited to participate in this 6-week pilot trial.

Intervention: Participants will perform supervised AT+BFR 3 times weekly for 32 minutes per session. A blood pressure cuff will be set between 60-80% of limb arterial occlusion with AT for 96 minutes per week of treadmill walking performed at 40-50% of heart rate reserve (HRR).

Participants in the AT-stdCare will perform 96 minutes per week of treadmill walking at 40-50% of HRR following the same schedule as AT+BFR, training 3 times per week for 32 minutes per session.

Outcomes: The main outcome measures will pertain to the feasibility of a larger trial and include recruitment rates, enrollment and adherence to the intervention, and retention for follow-up testing. The secondary outcomes will be focused on establishing effect sizes to power a larger trial. Effect sizes for the change in cardiorespiratory fitness and continuous glucose monitoring (CGM) outcomes will be determined to help select and power a primary outcome for a more definitive trial of AT+BFR.

Inclusion Criteria:

• Diagnosed with type 2 diabetes (5.7% < HbA1c < 9.0%)
• Not regularly physically active (150 mins moderate-vigorous physical activity per week)

Exclusion Criteria:

• Musculoskeletal issues preventing exercise training
• Unstable medications over the last 3 months
• Absolute contraindications to BFR (i.e. peripheral vascular disease)
• A self-reported diagnosis of low iron concentrations, anemia, or being treated for these conditions
• A diagnosis of any red blood cell-altering condition (i.e., sickle cell anemia, poikilocytosis)
• Currently living with any cardiovascular disease, which would impact the ability to participate in exercise safely
• Currently prescribed any medication which would impact the ability to use a heart rate monitor to accurately track intensity