Metabolic Adaptations in Response to High Intensity Interval Training in Obese Adults (HT)

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.

Study Overview

• Status: Completed
• Conditions: Glucose Intolerance
• Intervention / Treatment: Other: High Intensity Interval Training (HIIT); Other: Moderate-intensity continuous training (MICT)

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).

• Study Type: Interventional
• Enrollment (Actual): 120
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Michigan
    • Ann Arbor, Michigan, United States, 48178
      • Suzette Howton

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 40 years (Adult)
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: High Intensity Interval Training (HIIT); Obese adults with impaired glucose tolerance will be randomized into one of two different exercise training groups for a 3 month exercise intervention.	Other: High 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 .
Other: Moderate intensity continuous training (MICT); Obese adults with impaired glucose tolerance will be randomized into one of two different exercise training groups for a 3 month exercise intervention.	Other: Moderate-intensity continuous training (MICT); Moderate-intensity continuous training (MICT) = steady-state exercise at 60-70%HRmax for 45min. Representing a commonly prescribed exercise program.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Insulin Sensitivity	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.	Change from Baseline after 3 months of exercise training

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
VO2peak	Change in aerobic capacity between baseline and after 3 months of training	Change from Baseline after 3 months of exercise training
Resting Metabolic Rate	energy expenditure while at rest	Change from Baseline after 3 months of exercise training
Hepatic Fat %	Change in abundance of fat in the liver - reported as % area (measured by MRI)	Change from Baseline after 3 months of exercise training
Visceral Fat Area (cm^2)	Change in fat accumulation in the visceral region - measured by MRI	Change from Baseline after 3 months of exercise training

Collaborators and Investigators

• Sponsor: University of Michigan
• Investigators: Principal Investigator: Jeff Horowitz, University of Michigan

Publications and helpful links

General Publications

• Ryan BJ, Schleh MW, Ahn C, Ludzki AC, Gillen JB, Varshney P, Van Pelt DW, Pitchford LM, Chenevert TL, Gioscia-Ryan RA, Howton SM, Rode T, Hummel SL, Burant CF, Little JP, Horowitz JF. Moderate-Intensity Exercise and High-Intensity Interval Training Affect Insulin Sensitivity Similarly in Obese Adults. J Clin Endocrinol Metab. 2020 Aug 1;105(8):e2941-59. doi: 10.1210/clinem/dgaa345.

Study record dates

Study Major Dates

• Study Start (Actual): May 3, 2016
• Primary Completion (Actual): May 4, 2022
• Study Completion (Actual): May 4, 2022

Study Registration Dates

• First Submitted: March 2, 2016
• First Submitted That Met QC Criteria: March 7, 2016
• First Posted (Estimated): March 11, 2016

Study Record Updates

• Last Update Posted (Actual): August 24, 2026
• Last Update Submitted That Met QC Criteria: July 1, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Metabolic Diseases; Glucose Metabolism Disorders; Hyperglycemia; Nutritional and Metabolic Diseases; Glucose Intolerance; Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Physical Conditioning, Human; Exercise; High-Intensity Interval Training
• Other Study ID Numbers: HUM00106883

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO