Effect of Aerobic Interval Training on Cardiovascular Function in Type 2 Diabetes

Study Overview
=================
Brief Summary
-----------------
The study objectives are: To compare cardiovascular function in type 2 diabetes patients vs. healthy controls. To compare the effect of 8 weeks of aerobic interval training versus continuous moderate exercise on cardiovascular function in adults with type 2 diabetes. To examine the mechanisms underlying the exercise-related changes in cardiovascular function. The investigators hypothesize that compared to continuous moderate intensity exercise training, interval training will be more effective in improving cardiovascular function in adults with type 2 diabetes.

Detailed Description
-----------------
Cardiovascular function will be measured at baseline in adults with type 2 diabetes and in age-matched healthy controls. Research volunteers with type 2 diabetes who meet the inclusion criteria will be randomized to the aerobic interval training group, continuous moderate exercise group or non-exercise control group. At the end of the 8-week randomized control exercise intervention, baseline measures will be repeated.

Official Title
-----------------
Mechanisms of Cardiovascular Dysfunction and Effect of Aerobic Exercise Training in Adults With Type 2 Diabetes

Conditions
-----------------
Type 2 Diabetes

Intervention / Treatment
-----------------
* Other: High intensity aerobic interval training
* Other: Continuous moderate intensity exercise


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria for type 2 diabetes : Diagnosis of type 2 diabetes Sedentary or minimally physically active for at least the prior 1 year Able to give consent Inclusion criteria for healthy control group: Sedentary or minimally physically active for at least the prior 1 year Able to give consent Exclusion Criteria: History of diabetic proliferative retinopathy, autonomic or peripheral neuropathy History of any relevant cardiovascular diseases (myocardial infarction, angina pectoris, history of coronary artery bypass surgery or angioplasty, congestive heart failure, or arrhythmia) Hypertension (≥160 mmHg systolic or ≥100 mmHg diastolic) History of renal impairment History of gout or hyperuricemia History of hepatic disease or infection with hepatitis B, C History of seizures, or other relevant on-going or recurrent illness Recent (within 3 months) or recurrent hospitalizations Use of tobacco products >5 % weight change in the prior 6 months. Current intake of medications that may affect study results Premenopausal women taking oral contraceptives and postmenopausal women taking hormone replacement therapy. Pregnancy (positive urine pregnancy test) or lactation For the healthy control group, history of diabetes.

Ages Eligible for Study
-----------------
Minimum Age: 30 Years
Maximum Age: 79 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High intensity aerobic interval training<br>Type 2 diabetes subjects will complete 8 weeks of high intensity aerobic interval exercise training. | Other: High intensity aerobic interval training<br>* Supervised aerobic interval training will be performed on bicycles 4 times per week for 8 weeks. Each training session will last 40 minutes and will consist of 10-minute warm up at 70% of maximal heart rate (HRmax), four 4-minute intervals at 90% of HRmax with 3-min active recovery at 70% of HRmax and 5-minute cool down at 70% of HRmax.<br>|
| Experimental: Continuous moderate intensity exercise<br>Type 2 diabetes subjects will complete 8 weeks of continuous moderate intensity exercise training. | Other: Continuous moderate intensity exercise<br>* Supervised exercise training will be performed on bicycles 4 times per week for 8 weeks. Each training session will last 47 minutes and will consist of continuous moderate intensity cycling at 70% of HRmax.<br>|
| No Intervention: Non-exercise control group<br>Type 2 diabetes subjects assigned to the non-exercise control group will maintain their normal lifestyle for 8 weeks. | |
| No Intervention: Healthy control group<br>Healthy subjects will be assigned to the healthy control group and will undergo baseline measures only. | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in vascular endothelial function | Brachial flow mediated dilation using ultrasonography | At baseline and after 8 weeks of exercise training | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in factors related with endothelial function | Blood and cellular markers of adiponectin, oxidative stress and inflammation. | At baseline and after 8 weeks of exercise training | 
| Change in arterial stiffness | Arterial stiffness (pulse wave velocity) and wave reflection (augmentation index) will be measured using the SphygmoCor device. | At baseline and after 8 weeks of exercise training | 
| Change in cardiac function | Left ventricular systolic and diastolic function will be measured using echocardiography. | At baseline and after 8 weeks of exercise training | 
| Change in maximal oxygen consumption | Maximal oxygen consumption will be measured using online computer-assisted open-circuit spirometry during incremental treadmill exercise. | At baseline and after 8 weeks of exercise training |