HIIT in Isolated IFG: A Proof-of-Concept Study
- Conditions
- Isolated Impaired Fasting Glucose
- Interventions
- Behavioral: Routine dietary habits and physical activity.Behavioral: High-Intensity Interval TrainingDevice: Continuous glucose monitoring (CGM) (Dexcom G6 Pro CGM sensor)
- Registration Number
- NCT06143345
- Lead Sponsor
- Emory University
- Brief Summary
This pilot randomized controlled trial will involve 34 physically inactive adults aged 35-65 years with overweight or obesity and isolated impaired fasting glucose (i-IFG). The study aims to assess the feasibility of recruiting and retaining participants, implementing study procedures, and evaluating the acceptability of a high-intensity interval training (HIIT) intervention. Additionally, it will investigate the preliminary efficacy of HIIT in reducing fasting plasma glucose levels and addressing the pathophysiology of i-IFG.
- Detailed Description
This 1:1 proof-of-concept randomized controlled trial (RCT) will involve 34 physically inactive adults aged 35-65 years who are overweight or obese and have isolated impaired fasting glycemia (i-IFG). Potentially eligible individuals identified through Emory's MyChart electronic health care records system will undergo initial screening via phone calls. Individuals meeting the eligibility criteria will be invited to the Georgia Clinical and Translational Science Alliance at Emory University Hospital in Atlanta for further assessment. During their visit, participants will complete questionnaires, undergo an oral glucose tolerance test, and provide blood samples for insulin. Individuals identified with i-IFG will be randomized into the intervention or control groups.
Individuals assigned to the intervention group will participate in supervised high-intensity interval training (HIIT) sessions using stationary Spin cycle ergometers, in groups of five or fewer. They will wear continuous glucose monitoring (CGM) devices for 10 days before the intervention, throughout the 8-week intervention period, and for 10 days post-intervention. The intervention will be conducted three times a week for eight weeks at the Aerobic Exercise Laboratory in the Rehabilitation Hospital at Emory University. Control participants will be instructed to refrain from engaging in intense physical activities during the study period and will also wear CGM devices for the same duration. All participants will receive instructions to maintain a eucaloric diet throughout the study.
At baseline and after eight weeks, all participants will undergo physical measurements (anthropometrics, blood pressure, and body composition) as well as biochemical measurements (glucose and insulin levels). Additionally, participants in the intervention group will be invited to participate in qualitative in-depth interviews both before and after the HIIT intervention and will complete an intervention acceptability questionnaire upon completion.
The primary outcomes include feasibility metrics, measures of intervention feasibility, acceptability, and appropriateness, and participants' experiences, perceptions, and satisfaction with the HIIT intervention, as well as facilitators and barriers to participation. Secondary outcomes include: 1) Between-group differences in changes from baseline to 8 weeks in mean fasting plasma glucose and insulin levels, indices of β-cell function and insulin resistance, and physical measurements; and 2) CGM metrics: a) Between-group differences in the proportion of time and mean time spent in nocturnal (00:00-06:00) \[58\] normoglycemia (60 to \<100 mg/dl) during the 8-week intervention period and the 10 days following the intervention; b) Within-participant differences in the proportion of time and mean time spent in nocturnal (00:00-06:00) normoglycemia (60 to \<100 mg/dl) between exercise and non-exercise days during the 8-week intervention period.
Recruitment & Eligibility
- Status
- NOT_YET_RECRUITING
- Sex
- All
- Target Recruitment
- 34
Not provided
Not provided
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Control Group Routine dietary habits and physical activity. Control participants will be asked to maintain their routine dietary habits and physical activity levels. Control Group Continuous glucose monitoring (CGM) (Dexcom G6 Pro CGM sensor) Control participants will be asked to maintain their routine dietary habits and physical activity levels. Intervention Group High-Intensity Interval Training Intervention participants will complete 24 supervised high-intensity interval training (HIIT) sessions over 8 weeks, with 3 sessions per week on alternate days. Each HIIT session will consist of a 5-minute warm-up, followed by an interval-based workout phase that includes steady up-tempo cadences, sprints, and climbs, interspersed with recovery periods. The session will conclude with a 5-minute cooldown. Intervention Group Continuous glucose monitoring (CGM) (Dexcom G6 Pro CGM sensor) Intervention participants will complete 24 supervised high-intensity interval training (HIIT) sessions over 8 weeks, with 3 sessions per week on alternate days. Each HIIT session will consist of a 5-minute warm-up, followed by an interval-based workout phase that includes steady up-tempo cadences, sprints, and climbs, interspersed with recovery periods. The session will conclude with a 5-minute cooldown.
- Primary Outcome Measures
Name Time Method Response rate in % Baseline No. of individuals responded to the invitation/No. of individuals invited.
Screening yield in % Baseline No. of individuals diagnosed with i-IFG/No. of individuals screened.
Enrolment rate in % Baseline No. of individuals enrolled/No. of individuals diagnosed with i-IFG.
Time to enrollment (mins) Baseline Average time taken from sending the invitation to enrolling one participant in the trial.
Intervention compliance in % 8 weeks No. of HIIT sessions attended/Total no. of HIIT sessions.
Program costs (USD) From baseline to 8 weeks Includes screening cost, cost of procedures, intervention cost, participant incentives, and other costs.
Staff time (mins) From baseline to 8 weeks Time spent screening and recruiting participants, time spent delivering the intervention, time spent making phone calls to participants, time spent implementing the study procedures, and time spent on baseline and follow-up assessments.
Retention rate in % 8 weeks No. of participants attended follow-up visits/No. of participants enrolled.
Feasibility of Intervention Measure (FIM) score 8 weeks The FIM scale will evaluate the feasibility of the intervention, encompassing questions regarding its implementability, possibility, doability, and ease of use. Responses to the questions in the questionnaire will be recorded on a Likert scale of 1 to 5. The mean total score will be calculated by combining the individual Likert points. Higher scores on the FIM scale indicate greater intervention feasibility.
Theoretical Framework of Acceptability (TFA) score 8 weeks The acceptability of the intervention will be assessed through the Theoretical Framework of Acceptability (TFA) questionnaire, which explores affective attitude, burden, ethicality, perceived effectiveness, intervention coherence, self-efficacy, opportunity costs, and general acceptability.
Intervention Appropriate Measure (IAM) score 8 weeks The Intervention Appropriate Measure (IAM) will evaluate the appropriateness of the intervention, including questions about its fittingness, suitability, applicability, and alignment with participants' needs.
- Secondary Outcome Measures
Name Time Method Diastolic blood pressure in mmHg 8 weeks Change in diastolic BP from baseline to 8 weeks will be compared between study groups.
Insulinogenic index (IGI) 8 weeks IGI is a measure of early-phase insulin secretion.
Oral Disposition Index (DIO) 8 weeks DIO is a measure of ß-cell function.
Homeostatic Model Assessment of ß-cell function (HOMA-B) 8 weeks HOMA-B is a measure of ß-cell function.
Matsuda index 8 weeks Matsuda index is a measure of insulin resistance.
Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) 8 weeks HOMA-IR is a measure of insulin resistance.
Hepatic Insulin Resistance Index (HIRI) 8 weeks HIRI is a measure of hepatic insulin resistance.
Muscle Insulin Sensitivity Index (MISI) 8 weeks MISI is a measure of muscle insulin resistance.
Fat percent (%) 8 weeks Fat percent will be obtained by bioimpedance analysis.
Fat mass (kg) 8 weeks Fat mass will be obtained by bioimpedance analysis.
Muscle mass (kg) 8 weeks Muscle mass will be obtained by bioimpedance analysis.
Visceral adipose tissue mass (kg) 8 weeks Visceral adipose tissue mass will be obtained by bioimpedance analysis.
CGM metric: Proportion of time spent in nocturnal (00:00-06:00) normoglycemia (60 to <100 mg/dl) 10 days following the intervention Proportion of time spent in nocturnal (00:00-06:00) normoglycemia (60 to \<100 mg/dl) during the 10 days following the intervention.
CGM metric: Mean time spent in nocturnal (00:00-06:00) normoglycemia (60 to <100 mg/dl) 10 days following the intervention Mean time spent in nocturnal (00:00-06:00) normoglycemia (60 to \<100 mg/dl) during the 10 days following the intervention.
Waist circumference in cm 8 weeks Change in waist circumference from baseline to 8 weeks will be compared between study groups.
Waist-to-hip ratio 8 weeks Change in waist-to-hip ratio from baseline to 8 weeks will be compared between study groups.
Systolic blood pressure in mmHg 8 weeks Change in systolic BP from baseline to 8 weeks will be compared between study groups.
Weight in kg 8 weeks Weight will be measured using a digital weighing scale (Welch Ally-Scale-Tronix, NY, USA) with precision to the nearest 0.1 kg. The change in weight from baseline to 8 weeks will be compared between the intervention and control groups.
Fasting plasma glucose (mg/dl) 8 weeks Change in fasting plasma glucose from baseline to 8 weeks will be compared between study groups.
Fasting insulin (µU/ml) 8 weeks Change in fasting insulin from baseline to 8 weeks will be compared between study groups.
BMI in kg/m2 8 weeks Change in BMI from baseline to 8 weeks will be compared between study groups.