This study compares aerobic exercise training performed before breakfast (i.e., in the fasted state) to similar training performed after breakfast in people with type 2 diabetes. Training will take place over 16 weeks.

People with type 2 diabetes (T2D) are encouraged to increase their physical activity (PA). Sometimes, increasing the amount of PA can be difficult. Therefore, simply recommending that individuals preform more exercise may not be effective in the long term. Recent short-term studies have started to explore how to maximize the effect of a single bout of exercise. For example, short term studies suggest that exercise performed after a meal may decrease blood sugars more than exercise performed after a meal. However, research in people without diabetes shows this may not be the best approach in the long-term. To date, no long-term study has compared the effects of exercise performed at different times of the day in people with T2D.

This study will compare the effects of 16 weeks of regular exercise before breakfast compared to 16 weeks of regular exercise after breakfast. It is expected that exercise before breakfast (i.e., in the fasted state) will lead to greater improvements in blood sugar control, without the addition of more exercise. It could be very motivating for people with diabetes to know that they can get more benefits from exercise by changing when exercise is performed, rather than trying to increase the amount of exercise.

Inclusion Criteria:

• Physician diagnosed type 2 diabetes
• Treated with diet and/or glucose lowering medications, but not insulin, for at least 6 months
• Sedentary (defined as reaching <150 minutes of aerobic exercise per week)
• A1C below 9.0%
• BMI ≥25 kg/m2
• Central obesity as determined by waist circumference according to Diabetes Canada cutoffs:
• greater or equal to 94cm for males of European, Sub-Saharan African, Eastern Mediterranean and Middle Eastern descent,
• greater or equal to 90cm for males of South Asian, Chinese, Japanese, South and Central American descent,
• greater or equal to 80cm for females
• Able to walk for 50 minutes

Exclusion Criteria:

• Smoking
• Consuming more than 10 alcoholic drinks/week
• History of stroke, myocardial infarction, or coronary artery disease
• Resting heart rate <100 bpm
• Resting blood pressure <160/100 mmHg
• Implantable device, such as a pacemaker, that would not be safe for Magnetic Resonance Imaging

We plan to share all of the data related to study outcomes pm am open access website through the University of Alberta "Education and Research Archive" (ERA). Individual participant characteristics that could be used to identify participants (age, sex, height, weight) will not be be placed on ERA.

The data will become available one year after the completion of the trial.

The outcome data will be open access through the University of Alberta "Education and Research Archive" (ERA) website. Other participant characteristics will be available as meta-data.

For most outcomes, including the primary outcome, the outcome assessor will be unaware of group allocation.