Blood Flow Responses to an Oral Glucose Tolerance Test in Type 2 Diabetes
| Status: | Completed |
|---|---|
| Conditions: | Endocrine, Diabetes |
| Therapuetic Areas: | Endocrinology |
| Healthy: | No |
| Age Range: | 30 - 65 |
| Updated: | 4/21/2016 |
| Start Date: | August 2009 |
| End Date: | September 2010 |
Acute Cardiovascular and Metabolic Effects of Exercise Training in Individuals
The investigators wish to determine whether a short period of exercise training (5-10 days)
improves the metabolic and cardiovascular response of people with or at risk of developing
type 2 diabetes to eating a meal. In healthy people, blood flow to skeletal muscles
increases after eating a meal, and this helps to regulate blood sugar levels by delivering
blood sugar to muscles where it can be stored or metabolized. In people with or at risk of
type 2 diabetes, blood flow does not increase as much after eating a meal, and this may
contribute to elevated blood sugar concentrations observed in these individuals. The
investigators wish to determine whether exercise can improve this response.
improves the metabolic and cardiovascular response of people with or at risk of developing
type 2 diabetes to eating a meal. In healthy people, blood flow to skeletal muscles
increases after eating a meal, and this helps to regulate blood sugar levels by delivering
blood sugar to muscles where it can be stored or metabolized. In people with or at risk of
type 2 diabetes, blood flow does not increase as much after eating a meal, and this may
contribute to elevated blood sugar concentrations observed in these individuals. The
investigators wish to determine whether exercise can improve this response.
Insulin resistance is characterized by decreased sensitivity to the metabolic actions of
insulin (glucose disposal) and is a hallmark of obesity and type 2 diabetes (T2D). Insulin
resistance is also a prominent component of cardiovascular diseases (CVD), including
hypertension, coronary artery disease, and atherosclerosis, which are characterized by
endothelial dysfunction. Insulin stimulates two distinct signaling pathways in the
endothelium. One produces the vasodilator nitric oxide (NO) through the insulin receptor
substrate-1(IRS-1)/endothelial NO synthase (eNOS) pathway while the other stimulates
production of endothelin-1 (ET-1), a vasoconstrictor, through the mitogen activated protein
kinase (MAPK) pathway. Insulin-mediated glucose disposal is largely dependent upon the
vasodilatory effects of insulin; however, in T2D, insulin-stimulated dilation is impaired as
a result of an imbalance in NO and ET-1 production, leading to diminished microvascular
perfusion and skeletal muscle glucose delivery in response to insulin. The effects of
exercise on insulin signaling/action in the endothelium are not fully understood. The
purpose of this study is determine the acute effects of aerobic exercise training on
cardiometabolic responses to meal ingestion in individuals with insulin resistance or T2D.
We will recruit 30 previously sedentary (<60 minutes of planned exercise/week) men and women
with insulin resistance (pre-diabetes) or T2D for participation in this study. Participants
will undergo a screening procedure, including telephone screening and physical examination,
as well as determination of body composition and fitness. Participants will be asked to
complete 5-10 days of supervised exercise training and will undergo testing to assess
cardiovascular and metabolic responses to an oral glucose tolerance test, including muscle
sympathetic nerve activity, blood flow, and circulating glucose and insulin concentrations
at baseline and following training. In addition, participants will use continuous glucose
monitoring systems for 3 days at baseline and during 3 days of exercise training to assess
the effects of acute exercise on postprandial glucose responses to mixed meals in
free-living individuals. The overall aim of the project is to determine whether or not acute
exercise training influences postprandial metabolic, vascular or autonomic nervous system
responses in individuals with insulin resistance or T2D.
insulin (glucose disposal) and is a hallmark of obesity and type 2 diabetes (T2D). Insulin
resistance is also a prominent component of cardiovascular diseases (CVD), including
hypertension, coronary artery disease, and atherosclerosis, which are characterized by
endothelial dysfunction. Insulin stimulates two distinct signaling pathways in the
endothelium. One produces the vasodilator nitric oxide (NO) through the insulin receptor
substrate-1(IRS-1)/endothelial NO synthase (eNOS) pathway while the other stimulates
production of endothelin-1 (ET-1), a vasoconstrictor, through the mitogen activated protein
kinase (MAPK) pathway. Insulin-mediated glucose disposal is largely dependent upon the
vasodilatory effects of insulin; however, in T2D, insulin-stimulated dilation is impaired as
a result of an imbalance in NO and ET-1 production, leading to diminished microvascular
perfusion and skeletal muscle glucose delivery in response to insulin. The effects of
exercise on insulin signaling/action in the endothelium are not fully understood. The
purpose of this study is determine the acute effects of aerobic exercise training on
cardiometabolic responses to meal ingestion in individuals with insulin resistance or T2D.
We will recruit 30 previously sedentary (<60 minutes of planned exercise/week) men and women
with insulin resistance (pre-diabetes) or T2D for participation in this study. Participants
will undergo a screening procedure, including telephone screening and physical examination,
as well as determination of body composition and fitness. Participants will be asked to
complete 5-10 days of supervised exercise training and will undergo testing to assess
cardiovascular and metabolic responses to an oral glucose tolerance test, including muscle
sympathetic nerve activity, blood flow, and circulating glucose and insulin concentrations
at baseline and following training. In addition, participants will use continuous glucose
monitoring systems for 3 days at baseline and during 3 days of exercise training to assess
the effects of acute exercise on postprandial glucose responses to mixed meals in
free-living individuals. The overall aim of the project is to determine whether or not acute
exercise training influences postprandial metabolic, vascular or autonomic nervous system
responses in individuals with insulin resistance or T2D.
Inclusion Criteria:
- Insulin resistant: diagnosed with pre-diabetes or fasting blood glucose >/= 100 mg/dL
- T2D: diagnosed by primary care physician
- BMI: less than 43 kg/m2
- Age: 30-65
Exclusion Criteria:
- Smoking
- Insulin use (other than once daily)
- Underlying conditions that limit ability to exercise safely
- Recent weight gain or loss (> 5% of body weight in 3 months)
- Physically active (> 30 min aerobic exercise, 2 d/wk)
- Recent (< 3 mo) changes in medication use or dose
- Uncontrolled T2D (HbA1c > 10%)
- Advanced retinopathy or neuropathy
- Pregnancy
We found this trial at
1
site
University of Kansas Medical Center The University of Kansas Medical Center serves Kansas through excellence...
Click here to add this to my saved trials
