BACKGROUND Resistance exercise training with free weights or weight machines clearly improves glucose (sugar) control in type 2 diabetes (T2D). However, many patients with T2D would prefer not to attend an exercise facility, for reasons of cost and/or convenience. Coinvestigator Jonathon Fowles has developed and pilot-tested a home-based exercise program for people with T2D using resistance bands. However, the effects of resistance-bands training (on glucose control in T2D have not been evaluated in a high-quality randomized trial. SPECIFIC AIMS To determine the effects of six months of progressive home-based resistance bands training (RBT) versus no RBT in people with T2D on blood glucose control (HbA1c, primary outcome), waist circumference, heart disease risk factors, and quality of life. METHODS A total of 100 T2D participants will be randomized to 2 arms: home-based RBT (RBT-H) or aerobic training only (ATO). Both groups will accumulate 150 minutes per week of aerobic exercise such as walking. The resistance exercise workout includes 12 exercises, targeting all major muscle groups. RBT-H subjects will complete most exercise at home with periodic supervision. SIGNIFICANCE The global burden of type 2 diabetes is increasing, and complications of the illness occur primarily in those whose glucose control is fair or poor. If exercise training with resistance bands improves glucose control, it could be beneficial to the large numbers of patients who cannot travel to a gym or cannot afford gym membership. If resistance exercise is then adopted by more patients, it is likely that the morbidity associated with type 2 diabetes will be decreased. This is particularly true if such training also improves quality of life, and more people are thus inclined to continue exercising in the long term.
BACKGROUND Resistance exercise training with free weights or weight machines clearly improves glycemic control in type 2 diabetes (T2D). However, many patients with T2D would prefer not to, or are not able to attend an exercise facility,for reasons of cost, comfort or convenience. Coinvestigator Dr. Jonathon Fowles developed a home-based exercise program for people with T2D using resistance bands. Before-after studies using this intervention have found improvements in glycemic control, strength, and blood pressure. However, the effects of resistance-bands training (RBT) on glycemic control in T2D have not been evaluated in a high-quality randomized trial. RESEARCH QUESTIONS To determine the effects of six months of progressive home-based RBT plus aerobic exercise, versus home-based aerobic exercise alone, in previously-sedentary people with T2D. METHODS After a 2-week run-in period to assess adherence, 100 T2D subjects not currently engaging in regular exercise will be randomized in equal numbers to 2 arms: primarily home-based RBT (RBT-H) or aerobic only control (ATO) . Both groups will complete aerobic training: accumulation of 150 minutes per week of walking or jogging, measured by accelerometers. The RBT workout will include 12 distinctive exercises, targeting all major muscle groups. Subjects will be trained in groups led by a Kinesiologist (exercise specialist) twice per week for two weeks during run-in. After randomization, the RBT-H group will perform RBT three times per week. RBT-H participants will perform RBT three times per week primarily at home, with supervised group sessions weekly in weeks 1-4, every 2 weeks in weeks 5-8, and every 4 weeks thereafter to ensure proper form and appropriate progression. Adherence to RBT will be verified through direct supervision of group sessions, and completion of detailed exercise logs for home-based and group sessions. Participants will photograph the log after each session and email the photo to a designated email address. Study outcomes will be assessed at baseline, 12 and 24 weeks post-randomization. Dietary advice will be standardized through repeated sessions with a dietician, and doses of medications altering glucose, lipids and BP will be held constant unless change is medically urgent. Primary analyses will be intention-to-treat, using repeated measures mixed modeling. Per-protocol analyses will be done including only subjects who completed \>70% of prescribed exercise sessions and all end-of-study outcome measures. SIGNIFICANCE The global burden of type 2 diabetes is increasing, and complications of the illness occur primarily in those whose glycemic control is fair or poor. If home-based exercise training with resistance bands improves glycemic control and other vascular risk factors, it could be beneficial to the large numbers of patients who prefer not to have to travel to a gym or cannot afford gym membership. If resistance exercise is then adopted by more patients, it is likely that the morbidity associated with type 2 diabetes will be decreased. This is particularly true if such training also improves quality of life, and more people are thus inclined to continue exercising in the long term.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
72
All subjects will participate in a 10-week ramp-in period with the goal of achieving 150 minutes of moderate-to-vigorous physical activity per week. Walking and jogging will be the primary modes of achieving the prescribed aerobic activity as these are the modes of aerobic exercise that are most accurately recorded by an accelerometer. Subjects will use the Rate of Perceived Exertion (RPE) to guide aerobic exercise intensity. Aerobic activity will be objectively monitored by the Technogym MyWellness Key (MWK) accelerometer, which is a lightweight device worn on the waistband.
The bands + AT group will engage in RBT 3 times per week, progressing to 3 sets of 10-15 repetitions of 12 exercises. The exercises will be: chair squat, sitting chest press, seated rear fly, seated row, overhead press, lateral raise, biceps curl, triceps extension, leg extension, hamstring curl, gluteal extension, and abdominals. The resistance band exercise sessions will be between 25-60 minutes. Participants in this group will attend supervised group sessions weekly in weeks 1-4, every 2 weeks in weeks 5-8, and every 4 weeks thereafter to ensure proper form and appropriate progression. Participants in this group will be responsible to complete all remaining sessions (a total of 3 per week, including supervised sessions) at home on their own time.
Richmond Road Diagnostic and Treatment Centre
Calgary, Alberta, Canada
RECRUITINGTesting of Strength
The maximum weight that can be lifted 8 times while maintaining proper form (8RM) will be determined for chest press (upper body) and leg press (lower body).
Time frame: Baseline, 12 weeks, 24 weeks
Blood Pressure
Three measures of systolic and diastolic blood pressure (BP) will be taken at 2-minute intervals using a BP-Tru automated BP monitor (BP-Tru, Coquitlam, BC), with the subject sitting with back supported; the mean of the lower two measures will be taken as the true BP.
Time frame: Baseline, 12 weeks, 24 weeks
Smoking
will be assessed by self-report (number of cigarettes/day). The smoking rate is expected to be low and we do not expect intergroup differences. We will gather this information because smoking, an important predictor of diabetic complications including CVD, is used in the UKPDS Outcomes Model.
Time frame: baseline
Traditional lipids
Total cholesterol, HDL-Cholesterol and triglycerides will be measured by enzymatic colorimetric assays, and LDL-C calculated using the Friedewald equations. Total cholesterol/HDL-cholesterol ratio will be calculated.
Time frame: Baseline, 12 weeks, 24 weeks
Apolipoproteins
Apolipoprotein B (ApoB), Apolipoprotein A-1 (ApoA1), ApoB/ApoA1 ratio.
Time frame: Baseline, 12 weeks, 24 weeks
HSCRP
Addition of HSCRP (High-sensitivity C-reactive Protein) levels to cardiac risk prediction equations can provide incremental risk discrimination beyond that provided by age, sex, smoking, BP, and diabetes.
Time frame: Baseline, 12 weeks, 24 weeks
Moderate-vigourous aerobic exercise
Weekly time spent in moderate-to-vigourous intensity physical activity (i.e. greater than 3 METs) as measured by the MyWellness Key accelerometer will be collected via the web-based interface.
Time frame: every week from baseline to 24 weeks
The UKPDS Outcomes Model
is a computer simulation model for forecasting the occurrence of seven diabetes-related complications.
Time frame: Baseline, 12 weeks, 24 weeks
Satisfaction with the exercise program
Structured interview.
Time frame: 12 and 24 weeks
Continued participation in exercise after end of intervention
telephone interviews every 3 months for 2 years after the end of the intervention period.
Time frame: 3, 6, 9, 12, 15, 18, 21, 24 months after completion of the intervention
Medication Changes
Medication and doses will be assessed. Changes (start/increased dose; stop/decreased dose) in medications altering glucose, lipids or blood pressure will be considered secondary outcomes.
Time frame: Baseline, 12 weeks, 24 weeks
Adverse Events
Participants will be questioned regularly at each clinic visit regarding adverse events, which will be tracked systematically using standard forms.
Time frame: Baseline, 12 weeks, 24 weeks
Hemoglobin A1c (A1C)
A1C reflects average blood glucose over the previous 2-3 months and is expressed as a percent (normal A1C 4-6%, target A1C in diabetes \<7%). A 1% absolute decrement in A1C (e.g. from 8.0% to 7.0%) is associated with a 37% lower risk of microvascular complications of diabetes. In epidemiological analyses, lower A1C was also associated with lower risk of CVD. There has never been a negative impact of A1C-lowering in exercise trials.
Time frame: Baseline, 12 weeks, 24 weeks
Weight
Taken in light clothing without shoes.
Time frame: Baseline, 12 weeks, 24 weeks
Waist circumference
Measured midway between the lowest rib and the top of the iliac crest.
Time frame: Baseline, 12 weeks, 24 weeks
Hip circumference
Measured around the widest portion of the buttocks.
Time frame: Baseline, 12 weeks, 24 weeks
SF-36 questionnaire
Used to assess health related quality of life.
Time frame: Baseline, 12 weeks, 24 weeks
Diabetes Distress Scale Questionnaire
Assesses emotional distress and functioning specific to living with diabetes.
Time frame: Baseline, 12 weeks, 24 weeks
EuroQOL EQ-5D questionnaire
Assesses five core domains of quality of life (mobility, self-care, ability to conduct usual activities, pain and discomfort, and anxiety and depression).
Time frame: Baseline, 12 weeks, 24 weeks
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