Clinical trial NCT00786019
Conditions: Type 2 Diabetes
Keywords: Type 2 Diabetes Blood Vessel Function Exercise Program Intervention Vitamin C Men Women Blood vessel function
Sponsor: University of Colorado, Denver
Start date: 2008-05-01; Completion date: 2011-10-01
Enrollment: 47 participants; Allocation: NA; Intervention model: SINGLE_GROUP

Brief summary:
This study will evaluate the effects of impaired blood flow regulation on exercise. It will also determine whether the effects are more important in the heart or in the skeletal muscle tissue during exercise. In addition, this study will decide whether temporarily reversing these problems will improve blood flow control, improve heart and muscle tissue function and help improve exercise capacity in person with type 2 diabetes. This study will do so using two methods: (1) by giving vitamin C intravenously (IV) and (2) a three month exercise training program. Up to 100 subjects will be enrolled in this study.

Detailed description:
The investigators have found that persons with type 2 diabetes have an impaired ability to perform exercise even without clinically apparent complications. The reasons for this marked abnormality are unknown but are important as the decreased ability to exercise could contribute to the decreased expenditure of physical activity frequently observed in this population and may potentially constitute an early marker of cardiovascular disease.

The investigators wish to evaluate the effects of impaired blood flow regulation on exercise capacity and whether the effects are more important in the heart or in the skeletal muscle tissue during exercise. In addition, the investigators are determining whether correcting these abnormalities by two methods of improving blood flow regulation (acutely infusing Vitamin C or three months of chronic exercise training) leads to improved blood flow regulation, improved heart and skeletal muscle tissue function and hence to better exercise capacity in person with type 2 diabetes. This information will provide a more mechanistic understanding of causes of abnormal exercise responses observed in person with type 2 diabetes as well as whether and to what degree responses are modifiable. Interventions that reverse the exercise defect may facilitate patient adherence to prescribed physical activity programs and potentially decrease cardiovascular mortality in this large segment of the population.

Arms: arm 1: All study subjects have ascorbic acid infusion during one exercise visit as well as a three month exercise training intervention.
Interventions: intervention 1: Exercise program intervention 2: Ascorbic Acid (Vitamin C)
Intervention descriptions: intervention 1: Three month exercise program located at the Anschutz Medical Campus at I-225 and Colfax. The program runs three times per week for about an hour each session. Gym is open Monday - Saturday during specific hours (morning, noon, evening). intervention 2: During one exercise study visit, 0.06 grams of Vitamin C per kilogram fat-free mass per 100 milliliters (mL) of normal saline administered; Subjects will receive a bolus of 100mL Vitamin C solution given at 5ml/minute over 20 minutes followed by a "drip-infusion" given at 1.7ml/minute.

Protocol documents: