Exercise Training and Glucose Metabolism in Aging
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Purpose
Diabetes and its associated complications affect more than 20 million Americans, and the prevalence of type 2 diabetes and impaired glucose tolerance rises dramatically with age such that 40% of Americans over age 60 are affected. In older adults, glucose metabolism may be affected by reduced skeletal muscle capillary supply, which limits insulin, glucose, and oxygen delivery to skeletal muscle. Reduced capillary supply to skeletal muscle is found in older individuals with impaired glucose tolerance and we hypothesize that this is due to reduced vascular growth factor expression, and chronic inflammation. Further, we hypothesize that reversal of a sedentary lifestyle through aerobic exercise training will increase insulin signaling and vascular growth factor expression, as well as decrease inflammation, to increase capillary supply to skeletal muscle, which contributes to improved glucose metabolism in older adults with IGT. This study will: 1) Determine the mechanisms underlying reduced skeletal muscle capillarization in older adults with impaired glucose tolerance; and 2) Determine the effect of aerobic exercise training-induced increases in skeletal muscle capillarization on glucose metabolism in older adults with impaired glucose tolerance.
| Condition | Intervention |
|---|---|
|
Type 2 Diabetes Mellitus Impaired Glucose Tolerance (Prediabetes) |
Behavioral: Aerobic exercise training Behavioral: Detraining (cessation of exercise) |
| Study Type: | Interventional |
| Study Design: | Allocation: Non-Randomized Endpoint Classification: Efficacy Study Intervention Model: Single Group Assignment Masking: Open Label Primary Purpose: Prevention |
| Official Title: | Aging, Angiogenesis and Metabolic Responses to Aerobic Exercise |
- Glucose utilization [ Time Frame: baseline, 24 weeks, 26 weeks ] [ Designated as safety issue: No ]
- 2-hr post-prandial plasma glucose level [ Time Frame: baseline, 24 weeks, 26 weeks ] [ Designated as safety issue: No ]
- skeletal muscle capillarization [ Time Frame: baseline, 24 weeks, 26 weeks ] [ Designated as safety issue: No ]
- vascular growth factor expression [ Time Frame: baseline, 24 weeks, 26 weeks ] [ Designated as safety issue: No ]
- phosphorylation of insulin signaling proteins [ Time Frame: baseline, 24 weeks, 26 weeks ] [ Designated as safety issue: No ]
- Skeletal muscle glucose transporter-4 expression and glycogen synthase activity [ Time Frame: baseline, 24 weeks, 26 weeks ] [ Designated as safety issue: No ]
- body composition (%fat) [ Time Frame: baseline, 24 weeks, 26 weeks ] [ Designated as safety issue: No ]
- cardiorespiratory fitness [ Time Frame: baseline, 24 weeks, 26 weeks ] [ Designated as safety issue: No ]
| Enrollment: | 218 |
| Study Start Date: | October 2006 |
| Study Completion Date: | June 2012 |
| Primary Completion Date: | June 2012 (Final data collection date for primary outcome measure) |
| Arms | Assigned Interventions |
|---|---|
|
Active Comparator: Arm 1
Older adults, normal glucose tolerance
|
Behavioral: Aerobic exercise training
24 weeks of aerobic exercise training: 3 times per week, 60 minutes per session, at 70% of maximal aerobic capacity
Behavioral: Detraining (cessation of exercise)
Cessation of exercise for 2 weeks
|
|
Experimental: Arm 2
Older adults, impaired glucose tolerance
|
Behavioral: Aerobic exercise training
24 weeks of aerobic exercise training: 3 times per week, 60 minutes per session, at 70% of maximal aerobic capacity
Behavioral: Detraining (cessation of exercise)
Cessation of exercise for 2 weeks
|
|
Experimental: Arm 3
Athletes, normal glucose tolerance
|
Behavioral: Detraining (cessation of exercise)
Cessation of exercise for 2 weeks
|
Eligibility| Ages Eligible for Study: | 50 Years to 75 Years |
| Genders Eligible for Study: | Both |
| Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Age 50-75 years
- Non-smoker >2 years
- Body mass index = 18-35 kg/m2
Exclusion Criteria:
- History of CAD or cerebrovascular disease that would preclude exercise
- Implantable defibrillator
- Active cancer
- Chronic pulmonary, thyroid, renal, liver, or hematological disease
- HIV positive or prone to malnutrition
- Sickle cell anemia
- Type 1 diabetes, or currently on medication to treat type 2 diabetes
- Poorly-controlled type 2 diabetes
- Poorly-controlled hypertension
- Taking medications including: beta-blockers, oral steroids, warfarin, certain statins, hormone replacement therapy (HRT), oral contraceptives (OCP), thiazolidinediones (TZD), or chronic steroids or nonsteroidal analgesics (NSAIDS) that may not be safely discontinued temporarily for specific procedures (i.e. for 72 hours prior)
- Allergic to lidocaine or heparin
- Recent weight change (>5kg in 3 months)
- Currently pregnant or nursing
- Physical impairment limiting exercise
- Dementia or unstable clinical depression
Contacts and Locations| United States, Maryland | |
| VA Maryland Health Care System, Baltimore | |
| Baltimore, Maryland, United States, 21201 | |
| Principal Investigator: | Steven J. Prior, PhD | VA Maryland Health Care System, Baltimore |
More Information
No publications provided
| Responsible Party: | Department of Veterans Affairs |
| ClinicalTrials.gov Identifier: | NCT00701051 History of Changes |
| Other Study ID Numbers: | CDA-2-039-08S, H-27940, 5P30AG028747-05 |
| Study First Received: | June 18, 2008 |
| Last Updated: | June 29, 2012 |
| Health Authority: | United States: Federal Government |
Additional relevant MeSH terms:
|
Diabetes Mellitus Diabetes Mellitus, Type 2 Glucose Intolerance Prediabetic State |
Glucose Metabolism Disorders Metabolic Diseases Endocrine System Diseases Hyperglycemia |
ClinicalTrials.gov processed this record on May 22, 2013