HIIT: A Proof-of-Concept Study

Effect of High-Intensity Interval Training on Fasting Hyperglycemia in People With Isolated Impaired Fasting Glucose: A Proof-of-Concept Study

This is a pilot randomized controlled trial of 20 physically inactive i-IFG adults aged 35-55 years with overweight or obesity. The investigators will test the effects of HIIT on fasting hyperglycemia, the pathophysiology of i-IFG, and continuous glucose monitoring (CGM) metrics compared with the control participants who will receive standard lifestyle recommendations. The research team will also examine the feasibility of conducting the study procedures and assess the acceptability of HIIT intervention.

Study Overview

• Status: Not yet recruiting
• Conditions: Obesity
• Intervention / Treatment: Other: High-Intensity Interval Training; Device: Continuous glucose monitoring (CGM) (Dexcom G6 Pro CGM sensor); Other: Standard exercise recommendations

Detailed Description

This is a "Proof-of-Concept" 1:1 parallel-group RCT of 20 physically inactive i-IFG participants aged 35-55 years with overweight or obesity. Interested individuals will be invited to come in a fasting state (8-10 hours of overnight fasting). They will be administered a short questionnaire with the eligibility criteria and the Seven- Day Physical Activity Recall (7 Day PAR), and undergo height and weight measurements.

On the first day of the intervention, each participant will be fitted with a Dexcom G6 Pro CGM sensor beneath the skin by trained study staff. Participants will wear the device 2 days before the first exercise session (baseline) and then will wear the device for 10 days. The CGM system includes a sensor, a transmitter, and a receiver. The sensor measures the interstitial fluid glucose levels every 5 minutes, and the transmitter sends glucose data wirelessly from the sensor to the receiver. Participants will undergo measurements at baseline and after 4 weeks of intervention. Height and weight will be measured using measuring scales based on standard protocols. Early-phase insulin secretion will be measured using the validated and widely used insulinogenic index ([I30-I0]/[G30-G0]) with insulin and glucose levels at 0 and 30 min of the OGTT. Hepatic IR will be assessed using HIRI (glucose0-30[AUC] insulin0-30[AUC]), which correlates strongly with the direct measure of hepatic IR from euglycemic insulin clamps. After 4 weeks, intervention acceptability will be assessed using a short questionnaire with questions about the use of Spin bikes, timing, frequency and the number of exercise sessions, motivation to participate in the intervention, facilitators and barriers to participate in the intervention, and satisfaction with the intervention.

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Sathish Thirunavukkarasu, PhD; Phone Number: 404-778-3771; Email: sathish.thirunavukkarasu@emory.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. males and females of any race or ethnicity aged 35-55 years;
2. overweight (body mass index [BMI] 25.0 to <30.0 kg/m2)24 or obese (BMI ≥30.0 kg/m2);
3. history of prediabetes; and
4. physically inactive (<150 min of moderate-intensity or <75 min of vigorous-intensity aerobic physical activity/week)

Exclusion Criteria:

1. history of diabetes;
2. no exercise training in the past 6 months;
3. pregnant women;
4. smokers;
5. taking glucose-lowering drugs (e.g., metformin); and
6. those with chronic illnesses (e.g.,stroke).

Individuals satisfying the eligibility criteria will undergo a 3-step OGTT (0, 30, 120 min), and those diagnosed with i-IFG (FPG 110-125 mg/dl and 2-hr PG <140 mg/dl) will be recruited to the study.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention Group; Intervention participants will perform 12 sessions (3 sessions per week on alternate days) of supervised HIIT (cycling bouts eliciting 50-85% maximal heart rate) over 4 weeks. HIIT with Spin sessions will include a 5-min warm-up, then an interval-based workout phase with steady up-tempo cadences, sprints, and climbs (interspersed with recovery periods), followed by a 5-min cool down.	Other: High-Intensity Interval Training; HIIT with Spin sessions that will include a 5-min warm-up, then an interval-based workout phase with steady up-tempo cadences, sprints, and climbs (interspersed with recovery periods), followed by a 5-min cool down. All participants will wear Polar H10 chest strap heart rate sensors to ensure adequate intensity throughout each session and be instructed daily on their target heart rate range, computed using the Karvonen method. Phone calls will be made to the participants a day before each session to remind them about their scheduled session. Also, a log of the number of exercise sessions attended by each participant will be kept, which will be reviewed regularly to ensure high compliance with the intervention.; Other Names: HIIT intervention; Device: Continuous glucose monitoring (CGM) (Dexcom G6 Pro CGM sensor); The CGM system includes a sensor, a transmitter, and a receiver. The sensor measures the interstitial fluid glucose levels every 5 minutes, and the transmitter sends glucose data wirelessly from the sensor to the receiver. Participants will undergo measurements at baseline and after 4 weeks of intervention.; Other Names: Dexcom G6 Pro CGM sensor
Active Comparator: Control Group; Control participants will receive standard exercise recommendations (≥150 min of moderate-intensity physical activity per week distributed throughout the week with a minimum frequency of thrice a week).	Device: Continuous glucose monitoring (CGM) (Dexcom G6 Pro CGM sensor); The CGM system includes a sensor, a transmitter, and a receiver. The sensor measures the interstitial fluid glucose levels every 5 minutes, and the transmitter sends glucose data wirelessly from the sensor to the receiver. Participants will undergo measurements at baseline and after 4 weeks of intervention.; Other Names: Dexcom G6 Pro CGM sensor; Other: Standard exercise recommendations; Recommendation is ≥150 min of moderate-intensity physical activity per week distributed throughout the week with a minimum frequency of thrice a week.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Fasting plasma glucose (FPG) from baseline	Fasting plasma glucose will be compared at baseline and 4 weeks post-intervention between the intervention and control participants.	Baseline, 4 weeks post-intervention
Change in insulinogenic index from baseline	Early-phase insulin secretion will be measured using the insulinogenic index ([I30-I0]/[G30-G0]) with insulin and glucose levels at 0 and 30 min of the OGTT. Results will be compared between the intervention and control participants.	Baseline, 4 weeks post-intervention
Change in hepatic insulin resistance index (HIRI) from baseline	Hepatic insulin resistance (IR) will be assessed using HIRI (glucose 0-30[AUC] x insulin 0-30[AUC]). Results will be compared between study groups.	Baseline, 4 weeks post-intervention
Change in weight from baseline	Weight will be compared between intervention and control group.	Baseline, 4 weeks post-intervention
Change in BMI from baseline	BMI will be compared between intervention and control group.	Baseline, 4 weeks post-intervention
Time in range (TIR) of normoglycemia (70 to <110 mg/dl) overnight	Time in range (TIR) of normoglycemia (70 to <110 mg/dl) overnight measured by CGM will be compared between the intervention and control group.	4 weeks post-intervention
Change in mean fasting glucose on post-exercise day	Change in mean fasting glucose (one hour mean following 8-10 hours of fasting) on post- exercise day will be compared between study groups.	Baseline, 4 weeks post-intervention
Change in coefficient of variation in glucose levels	Coefficient of variation in glucose levels (overnight and overall) will be compared between study groups.	Baseline, 4 weeks post-intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Intervention Acceptability Questionnaire score	Intervention Acceptability Questionnaire will be measured using a Likert scale of 1-5: 1, Strongly disagree; 2, Disagree; 3, Neutral; 4, Agree; 5, Strongly agree. The minimum score will be 10 and the maximum score will be 50. Higher scores mean a better intervention acceptability.	Baseline, 4 weeks post-intervention

Collaborators and Investigators

• Sponsor: Emory University
• Collaborators: National Center for Advancing Translational Sciences (NCATS)
• Investigators: Principal Investigator: Sathish Thirunavukkarasu, PhD, Emory University

Study record dates

Study Major Dates

• Study Start (Estimated): March 1, 2024
• Primary Completion (Estimated): August 1, 2024
• Study Completion (Estimated): August 1, 2024

Study Registration Dates

• First Submitted: November 16, 2023
• First Submitted That Met QC Criteria: November 21, 2023
• First Posted (Estimated): November 22, 2023

Study Record Updates

• Last Update Posted (Estimated): November 22, 2023
• Last Update Submitted That Met QC Criteria: November 21, 2023
• Last Verified: November 1, 2023

More Information

Terms related to this study

• Other Study ID Numbers: STUDY00005855; UL1TR002378 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

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

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No