Glucose Intolerance
Conditions
Brief summary
The overall objectives are to: 1. Assess mechanisms underlying HIIT-induced improvements in insulin resistance at the whole-body, tissue, and cellular levels. 2. Systematically compare different HIIT regimens to help identify effective "doses" of HIIT that may be optimal for improving metabolic health in obese adults. 3. Assess the ability/willingness of obese subjects to adhere to a long-term HIIT program. Findings from these studies will greatly expand knowledge about the effects of HIIT on metabolic health, and will provide valuable information for development of programs aimed at maximizing key metabolic benefits of exercise.
Detailed description
If subjects are eligible for the study, they will be randomized into one of two different exercise training groups. Before training (and twice after 3 months of training) subjects will participate in a "clinical study" in which they will be required to stay overnight in the hospital. During the clinical study, the research team will perform a series of metabolic tests. Before and after the 3 months of training, the research team will assess subjects "free-living" 24h blood sugar control using a Continuous Glucose Monitor (CGM). The research team will measure several other relevant clinical markers (e.g., whole body and regional body fat assessments \[Dual Energy X-ray Absorptiometry (DEXA) and Magnetic Resonance Imager (MRI)\], hepatic lipid accumulation \[MRI analysis\], blood lipid profile, resting metabolic rate, glycated hemoglobin \[hemoglobin A1c\]). After the first 3 months of training, adherence to the subjects assigned training program will be tracked for the next 9 months (1 year of training in total). One year after initiating a training program, subjects will be asked to return to the clinic for a quick follow-up visit where the research team will complete some standard clinical assessments (e.g., body weight, body composition, blood pressure, and a blood sample).
Interventions
OTHERHigh Intensity Interval Training (HIIT)
(HIIT) 10 x 1 min. at \~90%HRmax - with low intensity warm-up, recovery, and cool down - total of 25 min/session .
Moderate-intensity continuous training (MICT) = steady-state exercise at 60-70%HRmax for 45min. Representing a commonly prescribed exercise program.
Sponsors
University of Michigan
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
No
Inclusion criteria
* Age: 18-40 * Body Mass Index: 30-40 kg/m2 * Waist circumference: 88-98cm for women and 100-110cm for men * No regularly planned exercise/physical activity * Women must have regularly occurring menses and must be premenopausal
Exclusion criteria
* EKG abnormalities as assessed by the cardiologist on the research team * Evidence/history of cardiovascular or metabolic disease * Medications known to affect lipid or glucose metabolism * Pregnant or lactating * Tobacco or e-cigarette use
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Insulin Sensitivity | Change from Baseline after 3 months of exercise training | A hyperinsulinemic-euglycemic clamp was used to assess peripheral insulin sensitivity. Briefly, a primed, continuous infusion of insulin (40 mU/m\^2/min) was administered; blood glucose was assessed every 5 minutes and 20% dextrose (D20 enriched with \[6-6 d2\]glucose) was infused at a variable rate to accommodate changes in blood glucose in order to maintain blood glucose at the participants' overnight fasted levels. About 2 hours after beginning the insulin infusion, when blood glucose concentration stabilized without further changes in the rate of D20 infusion for ≥ \~20 minutes, arterialized blood samples were collected every 5 minutes during the final 20 minutes of the clamp for the determination of steady state tracer-labeled glucose enrichment in plasma to calculate the rate of glucose disposal. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| VO2peak | Change from Baseline after 3 months of exercise training | Change in aerobic capacity between baseline and after 3 months of training |
| Resting Metabolic Rate | Change from Baseline after 3 months of exercise training | energy expenditure while at rest |
| Hepatic Fat % | Change from Baseline after 3 months of exercise training | Change in abundance of fat in the liver - reported as % area (measured by MRI) |
| Visceral Fat Area (cm^2) | Change from Baseline after 3 months of exercise training | Change in fat accumulation in the visceral region - measured by MRI |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORJeff Horowitz
University of Michigan
Participant flow
Recruitment details
Subjects were recruited via advertisements posted around the University of Michigan campus, around other local university campuses, by word of mouth, newspaper advertisements, web-based posting boards, and data sets from the University of Michigan Data Office for Clinical & Translational Research. Individuals who voluntarily completed our online general screening questionnaire in the past, and gave permission to keep the information from their responses, were also contacted for recruitment.
Pre-assignment details
73 subjects withdrew after eligibility was confirmed, but before starting the study protocol intervention for various reasons: 5 subjects became ineligible, 39 subjects declined participation, 2 subjects were withdrawn by study team due to issues with IVs, 3 subjects relocated and were no longer able to participate, 11 subjects were withdrawn by study team due to pharmacy issues, 13 subjects were lost to follow-up.
Baseline characteristics
| Characteristic | — |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 47 Participants |
| Ethnicity (NIH/OMB) Hispanic or Latino | 1 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 22 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants |
| Race (NIH/OMB) Black or African American | 5 Participants |
| Race (NIH/OMB) More than one race | 1 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 1 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 34 Participants |
| Sex: Female, Male Female | 34 Participants |
| Sex: Female, Male Male | 7 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 25 | 0 / 22 |
| other Total, other adverse events | 0 / 25 | 0 / 22 |
| serious Total, serious adverse events | 0 / 25 | 0 / 22 |
Outcome results
None listed