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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
15
The exercise intensity will be set at a workload corresponding to 40% of the workload obtained at VO2peak during the baseline progressive maximal exercise tests. Based on the anticipated fitness of the participants this should to an intensity of about 3.5 METs, which is similar to walking at a moderate pace.
The High Intensity Interval Exercise intervention will replicate all aspects of the Traditional Intensity Exercise with the exception of exercise intensity. The High Intensity Interval Exercise protocol will involve alternating between 1-minute intervals at 100% workload obtained at VO2peak followed by 3-minute recovery intervals at 20% of workload obtained at VO2peak (average = 40% ). As many complete intervals as possible will be completed during a training session (e.g., 7 intervals can be completed in a 30 min period (7 x 4 min = 28 min), with the remaining time spent at 40% peak workload to ensure a similar work output as the Traditional Intensity Exercise.
University of Alberta
Edmonton, Alberta, Canada
Feasibility of these exercise interventions in people with type 2 diabetes
* Recruitment * Adherence * Retention
Time frame: The feasibility of recruiting will be assessed over the 12-month recruitment phase. Adherence will be measured throughout the 14-week interventions. Retention will consider those who participate in the assessments before and after the intervention.
Intra-abdominal fat
Intra-abdominal fat will be estimated by previously validated technique of combining DXA and anthropometric measurements (Bertin 2000)
Time frame: During the week before and the week after the 14 week exercise interventions
Glycated hemoglobin (A1c)
Time frame: During the week before and the week after the 14 week exercise interventions
Glucose
Throughout the intervention period, we will take regular capillary blood glucose and lactate measures with a OneTouch® Ultra (LifeScan; Milpitas, CA, USA) portable glucose analyzer and a Accusport® (Boehringer Mannheim, Castle Hill, Australia) portable lactate analyzer. Samples will be taken 5 minutes before and 5 minutes after the exercise bout.
Time frame: Before and after individual exercise sessions
Plasma lipids and lipoproteins
* HDL cholesterol * LDL cholesterol * Total cholesterol * Triglycerides
Time frame: During the week before and the week after the 14 week exercise interventions
Daily steps
Daily steps will be measured with a Yamax SW-200Digiwalker Pedometer.
Time frame: During the week before the 14 week exercise interventions as well as during week 8 and week 14 of the interventions
Dietary intake
Dietary intake will be estimated by a standard 3-day food record (2 weekdays and 1 weekend).
Time frame: During the week before the 14 week exercise interventions as well as during week 8 and week 14 of the interventions
Anthropometrics
Anthropometrics will include: height, weight, waist circumference and hip circumference.
Time frame: During the week before and the week after the 14 week exercise interventions
Blood pressure
Time frame: During the week before and the week after the 14 week exercise interventions
Fitness
A graded maximal cycle ergometer test will be conducted on a cycle ergometer. The test will begin at a pedal rate of 60-65 rpm and a resistance of 0 kp. Pedaling rate will remain constant but resistance will increase by 0.5 kp every 2 min until exhaustion. Respiratory gases will be analyzed throughout (TrueMax; ParvoMedics, Salt Lake City, UT, USA). Heart rate was continuously monitored with a polar heart rate monitor (Polar Electro, NY, USA).
Time frame: During the week before and the week after the 14 week exercise interventions
Exercise Self-efficacy
A series of questions will be used to obtain preliminary information on the acceptability of the exercise protocols to the participants. The questions will include rating of perceived exertion (Borg Scale), as well as several indications of the participants confidence in being able to complete such exercise on a regular basis, including coping, task and scheduling self-efficacy. Other questions that related to fatigue will also be asked.
Time frame: During week 1, week 8 and week 14 of the exercise interventions
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