ObesityNCT04581980
Effects of Obesity and Intensity of Exercise on Ghrelin Levels
A study testing Exercise in people with Obesity and Insulin Resistance, run by University of Virginia at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 55 yearsHealthy volunteers can take part
- Conditions the study is for
- Obesity, Insulin Resistance, Cardiovascular Risk Factor
- What is being tested?
- Exercise
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteUnited States
- Study dates
- 14 Oct 2020to 16 Apr 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 55 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 18-55 years of age
- BMI between 18-40 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Virginia
Charlottesville, Virginia, 22902
About this study
Official title: Modulation of Ghrelin Release by Exercise Intensity: The Role of Obesity and Prediabetes Status
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.
Read the detailed description
The goal of this proposal is to characterize the effects of two exercise "intensity doses" on total ghrelin, acyl ghrelin, and des-acyl ghrelin in lean and obese adults with and without prediabetes. Ghrelin (TG) is involved in the regulation of appetite, energy balance, glucose metabolism and insulin sensitivity. Ghrelin exists in the blood in a des-acyl form (DAG ~78% of TG), and in an acylated form (AG ~22% of TG). Despite being less abundant, AG is has multiple actions that promote energy storage, including stimulation of appetite, inhibition of insulin release from the pancreas, and increases in adiposity via a widely characterized growth hormone secretagogue receptor. Conversely, DAG often opposes AG promoting negative energy balance (appetite suppression and reduced fat mass (FM)) and improving insulin sensitivity, acting through a receptor not yet identified. The optimal ratios of TG, DAG, and AG are not clear. Likewise, there is a need for targeted approaches that can effectively manipulate these peptides to aid in the prevention and/or treatment of obesity, metabolic syndrome, prediabetes and type 2 diabetes. Exercise provides a unique therapeutic approach in the treatment of dysregulated ghrelin.
Limited animal and human studies examining exercise and ghrelin release are mostly equivocal or only document TG and/or a single (e.g. AG) form of ghrelin. As DAG and AG can act synergistically, antagonistically, or have independent effects, the quantification of these peptides in response to exercise is critical to understanding the role of exercise on ghrelin release and ghrelin's exercise induced influence on overall glucose regulation and energy balance. Exercise intensity may be key, as exercise that elevates levels of lactate suppress AG and appetite post exercise. Here we propose to address this gap in knowledge by defining the role of acute exercise intensity, at doses above and below the lactate threshold, on TG, AG, and DAG release in lean and obese individuals with and without prediabetes. Specific Aim 1: Examine effects of exercise intensity on ghrelin, insulin, glucose and self-reported appetite. Hypothesis: Higher exercise intensity will result in differential effects on TG, AG, DAG, AG/DAG, insulin, and glucose AUC's, and appetite; affected by sex, obesity, abdominal visceral fat (AVF), and prediabetes status. Specific Aim 2: This is an exploratory aim using regression modeling to examine exercise-induced changes in ghrelin on glucose, insulin and appetite. Hypothesis: TG, AG, DAG and AG/DAG alterations will differentially predict changes in glucose metabolism, insulin sensitivity, and appetite. These alterations vary by sex, levels of obesity, AVF, and prediabetes. Results from this pilot/feasibility application will inform a larger submission that defines therapeutic exercise targets for TG, AG, and DAG, and examines the effects of individualized exercise training using precision exercise prescription techniques on ghrelin release.
- Conditions
- Obesity, Insulin Resistance, Cardiovascular Risk Factor
- Being tested
- Exercise
- Keywords
- exercise, ghrelin, insulin resistance, vascular function, obesity, prediabetes
- Medical subject headings
- Obesity, Insulin Resistance, Motor Activity, Prediabetic State
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ExerciseOther
Participants will exercise on a cycle ergometer
| Study group | Role | What they receive |
|---|---|---|
| Control | No intervention | This arm will receive no exercise |
| Moderate Intensity Exercise | Experimental | This group will exercise on a cycle ergometer (Lode Bike) at moderate intensity. Moderate intensity will be defined by the lactate threshold. A heart rate monitor will be utilized at all times to record heart rate. Receives: Other: Exercise |
| High Intensity Exercise | Experimental | This group will exercise on a cycle ergometer (Lode Bike) at high intensity. High intensity will be defined by an by 75% of the difference between the lactate threshold and peak. Receives: Other: Exercise |
What is being measured
The primary outcome is the main question the study is designed to answer.
Ghrelin
We will be analyzing plasma levels of acylated and deacylated ghrelin
Measured: Measured at 6 timepoints over 2-3 hours during each experimental visit
Secondary outcomes (2)
Appetite Questionnaire (VAS)
We will see how appetite may or may not change in response to exercise
Measured: Measured at 6 timepoints over 2-3 hours during each experimental visit
Vascular Function (brachial flow mediated dilation)
We will be measuring how the arteries respond (i.e. dilate) in response to exercise
Measured: Measured at 5 timepoints over 2-3 hours during each experimental visit
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Oct 2020
- Study start14 Oct 2020
- Primary completion16 Apr 2025
- Study completion16 Apr 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ObesityStudies of the same condition, open and under way.
- More trials run by University of VirginiaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Health services research
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Randomized, crossover design
- Masking
- None (open label)
- Enrolment
- 40 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Virginia
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Arthur L Weltman, University of Virginia
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04581980
- Sponsor's protocol ID
- 200241
- Other IDs
- 5R01DK129510-02
- Status last verified
- May 2024
- First submitted
- 1 Oct 2020
- Last updated
- 17 Sep 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Modulation of Ghrelin Release by Exercise Intensity: The Role of Obesity and Prediabetes Status
- ClinicalTrials.gov ID
- NCT04581980
- Acronym / sponsor ID
- 200241
- Conditions
- Obesity, Insulin Resistance, Cardiovascular Risk Factor
- Keywords
- exercise, ghrelin, insulin resistance, vascular function, obesity, prediabetes
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 40 participants (actual)
- Lead sponsor
- University of VirginiaUniversity, hospital or other
- Collaborators
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
- Study start
- 14 Oct 2020 (actual)
- Primary completion
- 16 Apr 2025 (actual)
- Study completion
- 16 Apr 2025 (actual)
- First posted
- 9 Oct 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
The goal of this proposal is to characterize the effects of two exercise "intensity doses" on total ghrelin, acyl ghrelin, and des-acyl ghrelin in lean and obese adults with and without prediabetes. Ghrelin (TG) is involved in the regulation of appetite, energy balance, glucose metabolism and insulin sensitivity. Ghrelin exists in the blood in a des-acyl form (DAG ~78% of TG), and in an acylated form (AG ~22% of TG). Despite being less abundant, AG is has multiple actions that promote energy storage, including stimulation of appetite, inhibition of insulin release from the pancreas, and increases in adiposity via a widely characterized growth hormone secretagogue receptor. Conversely, DAG often opposes AG promoting negative energy balance (appetite suppression and reduced fat mass (FM)) and improving insulin sensitivity, acting through a receptor not yet identified. The optimal ratios of TG, DAG, and AG are not clear. Likewise, there is a need for targeted approaches that can effectively manipulate these peptides to aid in the prevention and/or treatment of obesity, metabolic syndrome, prediabetes and type 2 diabetes. Exercise provides a unique therapeutic approach in the treatment of dysregulated ghrelin.
Limited animal and human studies examining exercise and ghrelin release are mostly equivocal or only document TG and/or a single (e.g. AG) form of ghrelin. As DAG and AG can act synergistically, antagonistically, or have independent effects, the quantification of these peptides in response to exercise is critical to understanding the role of exercise on ghrelin release and ghrelin's exercise induced influence on overall glucose regulation and energy balance. Exercise intensity may be key, as exercise that elevates levels of lactate suppress AG and appetite post exercise. Here we propose to address this gap in knowledge by defining the role of acute exercise intensity, at doses above and below the lactate threshold, on TG, AG, and DAG release in lean and obese individuals with and without prediabetes. Specific Aim 1: Examine effects of exercise intensity on ghrelin, insulin, glucose and self-reported appetite. Hypothesis: Higher exercise intensity will result in differential effects on TG, AG, DAG, AG/DAG, insulin, and glucose AUC's, and appetite; affected by sex, obesity, abdominal visceral fat (AVF), and prediabetes status. Specific Aim 2: This is an exploratory aim using regression modeling to examine exercise-induced changes in ghrelin on glucose, insulin and appetite. Hypothesis: TG, AG, DAG and AG/DAG alterations will differentially predict changes in glucose metabolism, insulin sensitivity, and appetite. These alterations vary by sex, levels of obesity, AVF, and prediabetes. Results from this pilot/feasibility application will inform a larger submission that defines therapeutic exercise targets for TG, AG, and DAG, and examines the effects of individualized exercise training using precision exercise prescription techniques on ghrelin release.
Study design
- Primary purpose
- Health services research
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 3
- Model description
- Randomized, crossover design
| Arm | Type | Receives |
|---|---|---|
| Control | No intervention | –This arm will receive no exercise |
| Moderate Intensity Exercise | Experimental | Other: ExerciseThis group will exercise on a cycle ergometer (Lode Bike) at moderate intensity. Moderate intensity will be defined by the lactate threshold. A heart rate monitor will be utilized at all times to record heart rate. |
| High Intensity Exercise | Experimental | Other: ExerciseThis group will exercise on a cycle ergometer (Lode Bike) at high intensity. High intensity will be defined by an by 75% of the difference between the lactate threshold and peak. |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- 18-55 years of age
- BMI between 18-40 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
Key exclusion criteria (5 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ExerciseParticipants will exercise on a cycle ergometer | Other | High Intensity Exercise, Moderate Intensity Exercise |
Primary outcome
Ghrelin
Time frame: Measured at 6 timepoints over 2-3 hours during each experimental visit
We will be analyzing plasma levels of acylated and deacylated ghrelin
2 secondary outcomes
Appetite Questionnaire (VAS)
Time frame: Measured at 6 timepoints over 2-3 hours during each experimental visit
Vascular Function (brachial flow mediated dilation)
Time frame: Measured at 5 timepoints over 2-3 hours during each experimental visit
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Sep 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Exercise in people with Obesity and Insulin Resistance, run by University of Virginia at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 17 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Ghrelin (time frame: Measured at 6 timepoints over 2-3 hours during each experimental visit). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Sep 2025.