Effects of Obesity and Intensity of Exercise on Ghrelin Levels
Effects of Obesity and Intensity of Exercise on Ghrelin Levels
This study is investigating the effect of different intensities of exercise on levels of the
 hormone, ghrelin. In addition, we will be examining the relationship between any exercise
 induced changes in ghrelin and insulin sensitivity, obesity, and vascular function.
Obesity increases the risk of disease. We will examine the impact of moderate and high
 intensity exercise on the hormone ghrelin and its two forms, acyl (AG) and des-acyl (DAG),
 which are suggested to influence appetite, glucose metabolism and vascular function. We will
 determine whether differential changes in total ghrelin, AG and DAG are associated with
 changes in appetite, insulin sensitivity and vascular function. Subjects will be categorized
 as; either lean or obese (BMI), and either normal fasting glucose or impaired glucose
 tolerant (oral glucose tolerance test). Each participant will undergo body composition
 analysis, and a maximal treadmill cardiopulmonary exercise test to determine lactate
 threshold and maximal oxygen uptake. Subjects will then complete three randomly assigned
 exercise sessions: a) control (rest), (b) moderate intensity exercise and, (c) high intensity
 exercise. Blood sampling and measures of vascular function will occur before, during and
 after each study. An ANOVA with repeated measures and logistic regression analyses will
 examine the differential impact of exercise intensity on the outcome measures. Data collected
 will be used to develop a precision exercise approach to treat obesity and abnormal glucose
 metabolism for a NIH grant submission. This project is related to the UVa emphasis in
 precision medicine.
Inclusion Criteria:

 -  40-52 years of age

 -  BMI between 18-35 kg/m2

 -  Untrained (reports less than 2 days/week of exercise)

 -  Weight stable (no significant loss/gain of more than 3kg in the past 3 months)

 -  Females must be premenopausal and report normal menstrual cycles

 Exclusion Criteria:

 -  History of diabetes, gastrointestinal disease, or endocrine disorder

 -  Smoking (must have quit at least 6 months prior)

 -  Disordered eating

 -  Females currently pregnant or undergoing fertility treatments

 -  The following medications (due to their effect on insulin sensitivity ,endothelial
 function and/or ghrelin secretion): Synthetic growth hormone, metformin, synthetic
 insulin, sulfonylureas, meglitinides, Thiazolidinediones, DPP-4 inhibitors, GLP-1
 receptor agonists, SGLT2 inhibitors , biguanides, alpha-glucosidase inhibitors,
 phosphodiesterase inhibitors, beta-blockers, alpha-blockers, ACE-inhibitors, ARB's,
 fibrates, glucocorticoids, olanzapine