Exercise Intensity, Glycemic Control and Abdominal Fat in People With Type 2 Diabetes: A Pilot Study

Body fat is an important risk factors for type 2 diabetes. However, not all body fat is the same. Research suggests that fat stored in the abdomen is most harmful. This is known as intra-abdominal fat. The objective of the proposed study is to understand the effect of exercise intensity on intra-abdominal fat and glucose control. Twenty participants with type 2 diabetes will be assigned to traditional or high intensity exercise. The exercise interventions will last a total of 14 weeks. Those in the traditional intensity group will exercise at an intensity comparable to walking. The high intensity group will alternate between 1 minute at high intensity and 3 minutes at low intensity. Both exercise groups will burn a similar amount of Calories and will exercise for the same amount of time. The exercise duration will start at 30 minutes per day. By the end of the study, it will be 60 minutes per day. All exercise sessions will be supervised. Body fat distribution will be estimated by a scanning machine called a DXA and anthropometric measures. Glycemic control will be measured from a blood sample. This study may not be of sufficient size to detect meaningful changes in these variables. However, it will provide information in regards to the preliminary efficacy, resource requirements and feasibility. Feasibility will include: recruitment, retention and adherence. Such information is essential for planning a more definitive trial. The identification of exercises that target greater reductions in abdominal fat will have important implications for the health of people with diabetes.

Inclusion Criteria:

• Men and women with type 2 diabetes.
• From 55-75 years of age (Women post-menopausal for at least 5 years).
• Sedentary: < 3 bouts of planed physical activity of >30 min per week.

Exclusion Criteria:

• Smoking (defined as more than one cigarette per day).
• Inability to speak and read English.
• Diseases known to affect body fat distribution (e.g., polycystic ovary syndrome, Cushing's syndrome, HIV-AIDS or lipodystrophies).
• Taking medications that may affect body fat distribution (e.g., Thiazolidinedione, Insulin, Growth Hormone).
• Limitations to regular exercise training (e.g., musculoskeletal limitations, heart disease, chronic obstructive pulmonary disease).
• Answering "yes" to any of the questions on the physical activity readiness questionnaire (PAR-Q).
• Having undergone major changes in physical activity, diet or medication in the previous 6 months (or be planning such changes in the next 4 months). Changes in physical activity will be considered as an increase or decrease of more than 1 hour per week. A change in body weight greater 3 kg will also lead to exclusion.
• Body weight > 300 lbs (maximum weight for Dual Energy X-Ray Absorptiometry (DXA) table).
• HbA1c > 0.09%
• blood pressure above 140/90 mmHg.
• LDL cholesterol above 3.5 mmol/L or TC:HDL-C above 5.0.
• Self-reported alcohol or substance abuse within the past twelve months, current consumption of more than 14 alcoholic drinks per week, and/or current acute treatment or rehabilitation program for these problems.
• Other medical or psychiatric factors that in the judgment of the principal investigators may interfere with study participation or the ability to follow the study protocol.