Effects of HIIT vs. TRE on Type 2 Diabetes Risk

BEHAVIORAL

High-intensity interval training

The 4-week HIIT intervention will use a stationary bicycle performed 3 times/week (a total of 12 sessions over the 4-week), performing at the CRL. All participants will perform a 20-minute HIIT protocol (20 repetitions of 10-seconds work time followed by 50-seconds resting/active recovery for the first two weeks, and 10 repetitions of 20-seconds work time followed by 100-seonds resting/active recovery for the rest of two weeks; targeted 90% HRmax) after 5-minute warm-up (10% HRmax). The supervisor (PI: Joon Young Kim and/or Graduate researcher: Wonhee Cho) will provide encouragement and supervision for exercise adherence. Heart rate (Polar, Polar Electro Oy, Kempele, Finland) and rating of perceived exertion (RPE; detail described in the questionnaire section) will be recorded.

BEHAVIORAL

Time-restricted eating

Participants randomized into the TRE group will be instructed to consume all their calories within a 10-hour period. We will instruct participants that they can choose their time-window (early TRE \[7am - 5pm\] or late TRE \[1pm - 11pm\]), but it must remain constant for the duration of the study. Further, we will give no restrictions on the type of foods and/or the quantities individuals can consume. We will ask individuals to maintain their diet for the duration of the study. Participants will be given clear instructions on their diet and how to use the "MyFitnessPal" application. Participants will have their total daily energy requirement calculated using the following formula (Basal metabolic rate \[BMR\] x activity level) and will be told to eat that amount within their allotted time window. BMR will be calculated when participants have their body composition taken by the InBody. Participants will be told to start their 4-week diet the following day after visit.

Weight (kg)

Time frame: Baseline and after 4 weeks of intervention

Weight is measured in kilograms (kg) using a calibrated digital scale.

Height (cm)

Time frame: Baseline and after 4 weeks of intervention

Height is measured in centimeters (cm) using a wall-mounted stadiometer.

Body Mass Index (BMI)

Time frame: Baseline and after 4 weeks of intervention

Weight and height will be combined to report BMI in kg/m².

Waist Circumference and Hip Circumference

Time frame: Baseline and after 4 weeks of intervention

Waist and hip circumferences are measured while participants stand straight with their arms extended outward. A non-elastic tape measure is wrapped around the waist and hip, and measurements are taken to the nearest centimeter (cm).

Blood Lipid Profile

Time frame: Baseline and after 4 weeks of intervention

Blood lipid profile, including total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C), and fasting glucose (FG) are measured in milligrams per deciliter (mg/dL) using the Cholestech LDX Analyzer. Blood samples are obtained via fingerstick, with the first drop wiped away and the second drop collected for analysis. Participants stand or sit comfortably during collection. After blood collection, the site is cleaned and covered with gauze and a bandage as needed. This procedure is minimally invasive and typically causes little discomfort.

Blood Pressure

Time frame: Baseline and after 4 weeks of intervention

Systolic blood pressure (SBP) and diastolic blood pressure (DBP) are measured in millimeters of mercury (mmHg), and resting heart rate (RHR) is measured in beats per minute (bpm) using an automated blood pressure monitor. Participants sit quietly for five minutes with minimal movement prior to measurement. A cuff is placed on the right upper arm (bicep area), and the monitor initiates inflation, deflation, and reinflation cycles. Participants are instructed not to move during the measurement process. All equipment is disinfected before and after each use with antiviral, antibacterial, and antifungal disposable wipes by a researcher wearing gloves.

Carotid-Femoral Pulse Wave Velocity

Time frame: Baseline and after 4 weeks of intervention

Carotid-femoral pulse wave velocity (PWV), a preclinical marker of cardiovascular disease (CVD), is measured in meters per second (m/s) using applanation tonometry (SphygmoCor, AtCor Medical). Participants are positioned supine on a padded exam table after resting quietly for approximately five minutes. Brachial blood pressure is measured in millimeters of mercury (mmHg) using an automated cuff device. Pressure waveforms are recorded at the carotid artery (neck) and femoral artery (upper leg) using a handheld tonometer. The time delay between carotid and femoral pulse waves is used to calculate PWV, an indicator of arterial stiffness. The procedure is non-invasive and typically requires approximately five minutes to complete.

Glucose (mg/dL)

Time frame: Baseline and after 4 weeks of intervention

After a 10- to 12-hour overnight fast, participants undergo a 2-hour oral glucose tolerance test (OGTT) at the Clinical Research Unit, SUNY Upstate Medical University. Venous blood samples are collected at -15, 0, 30, 60, 90, and 120 minutes relative to glucose ingestion. At time 0 minutes, participants consume a commercially prepared standard 75-gram glucose solution; youth participants receive 1.75 grams of glucose per kilogram of body weight, not exceeding 75 grams total. After the final blood collection at 120 minutes, participants are provided a snack and continue their study visit. Blood is collected in pre-chilled aprotinin/EDTA tubes and processed for analysis of glucose (mg/dL).

Insulin (μIU/mL)

Time frame: Baseline and after 4 weeks of intervention

After a 10- to 12-hour overnight fast, participants undergo a 2-hour oral glucose tolerance test (OGTT) at the Clinical Research Unit, SUNY Upstate Medical University. Venous blood samples are collected at -15, 0, 30, 60, 90, and 120 minutes relative to glucose ingestion. At time 0 minutes, participants consume a commercially prepared standard 75-gram glucose solution; youth participants receive 1.75 grams of glucose per kilogram of body weight, not exceeding 75 grams total. After the final blood collection at 120 minutes, participants are provided a snack and continue their study visit. Blood is collected in pre-chilled aprotinin/EDTA tubes and processed for analysis of insulin (μIU/mL).

C-peptide (ng/mL)

Time frame: Baseline and after 4 weeks of intervention

After a 10- to 12-hour overnight fast, participants undergo a 2-hour oral glucose tolerance test (OGTT) at the Clinical Research Unit, SUNY Upstate Medical University. Venous blood samples are collected at -15, 0, 30, 60, 90, and 120 minutes relative to glucose ingestion. At time 0 minutes, participants consume a commercially prepared standard 75-gram glucose solution; youth participants receive 1.75 grams of glucose per kilogram of body weight, not exceeding 75 grams total. After the final blood collection at 120 minutes, participants are provided a snack and continue their study visit. Blood is collected in pre-chilled aprotinin/EDTA tubes and processed for analysis of C-peptide (ng/mL).

Total glucagon-like peptide-1 (GLP-1) (pmol/L)

Time frame: Baseline and after 4 weeks of intervention

After a 10- to 12-hour overnight fast, participants undergo a 2-hour oral glucose tolerance test (OGTT) at the Clinical Research Unit, SUNY Upstate Medical University. Venous blood samples are collected at -15, 0, 30, 60, 90, and 120 minutes relative to glucose ingestion. At time 0 minutes, participants consume a commercially prepared standard 75-gram glucose solution; youth participants receive 1.75 grams of glucose per kilogram of body weight, not exceeding 75 grams total. After the final blood collection at 120 minutes, participants are provided a snack and continue their study visit. Blood is collected in pre-chilled aprotinin/EDTA tubes and processed for analysis of total glucagon-like peptide-1 (GLP-1) (pmol/L).

Glucose-dependent insulinotropic polypeptide (GIP) (pg/mL)

Time frame: Baseline and after 4 weeks of intervention

After a 10- to 12-hour overnight fast, participants undergo a 2-hour oral glucose tolerance test (OGTT) at the Clinical Research Unit, SUNY Upstate Medical University. Venous blood samples are collected at -15, 0, 30, 60, 90, and 120 minutes relative to glucose ingestion. At time 0 minutes, participants consume a commercially prepared standard 75-gram glucose solution; youth participants receive 1.75 grams of glucose per kilogram of body weight, not exceeding 75 grams total. After the final blood collection at 120 minutes, participants are provided a snack and continue their study visit. Blood is collected in pre-chilled aprotinin/EDTA tubes and processed for analysis of glucose-dependent insulinotropic polypeptide (GIP) (pg/mL).

Leptin (ng/mL)

Time frame: Baseline and after 4 weeks of intervention

After a 10- to 12-hour overnight fast, participants undergo a 2-hour oral glucose tolerance test (OGTT) at the Clinical Research Unit, SUNY Upstate Medical University. Venous blood samples are collected at -15, 0, 30, 60, 90, and 120 minutes relative to glucose ingestion. At time 0 minutes, participants consume a commercially prepared standard 75-gram glucose solution; youth participants receive 1.75 grams of glucose per kilogram of body weight, not exceeding 75 grams total. After the final blood collection at 120 minutes, participants are provided a snack and continue their study visit. Blood is collected in pre-chilled aprotinin/EDTA tubes and processed for analysis of leptin (ng/mL).

Adiponectin (μg/mL)

Time frame: Time Frame: Baseline and after 4 weeks of intervention

After a 10- to 12-hour overnight fast, participants undergo a 2-hour oral glucose tolerance test (OGTT) at the Clinical Research Unit, SUNY Upstate Medical University. Venous blood samples are collected at -15, 0, 30, 60, 90, and 120 minutes relative to glucose ingestion. At time 0 minutes, participants consume a commercially prepared standard 75-gram glucose solution; youth participants receive 1.75 grams of glucose per kilogram of body weight, not exceeding 75 grams total. After the final blood collection at 120 minutes, participants are provided a snack and continue their study visit. Blood is collected in pre-chilled aprotinin/EDTA tubes and processed for analysis of adiponectin (μg/mL).

Ghrelin (pg/mL)

Time frame: Baseline and after 4 weeks of intervention

After a 10- to 12-hour overnight fast, participants undergo a 2-hour oral glucose tolerance test (OGTT) at the Clinical Research Unit, SUNY Upstate Medical University. Venous blood samples are collected at -15, 0, 30, 60, 90, and 120 minutes relative to glucose ingestion. At time 0 minutes, participants consume a commercially prepared standard 75-gram glucose solution; youth participants receive 1.75 grams of glucose per kilogram of body weight, not exceeding 75 grams total. After the final blood collection at 120 minutes, participants are provided a snack and continue their study visit. Blood is collected in pre-chilled aprotinin/EDTA tubes and processed for analysis of ghrelin (pg/mL).

C-reactive protein (CRP) (mg/L)

Time frame: Baseline and after 4 weeks of intervention

After a 10- to 12-hour overnight fast, participants undergo a 2-hour oral glucose tolerance test (OGTT) at the Clinical Research Unit, SUNY Upstate Medical University. Venous blood samples are collected at -15, 0, 30, 60, 90, and 120 minutes relative to glucose ingestion. At time 0 minutes, participants consume a commercially prepared standard 75-gram glucose solution; youth participants receive 1.75 grams of glucose per kilogram of body weight, not exceeding 75 grams total. After the final blood collection at 120 minutes, participants are provided a snack and continue their study visit. Blood is collected in pre-chilled aprotinin/EDTA tubes and processed for analysis of C-reactive protein (CRP) (mg/L).

Interleukin-6 (IL-6) (pg/mL)

Time frame: Baseline and after 4 weeks of intervention

After a 10- to 12-hour overnight fast, participants undergo a 2-hour oral glucose tolerance test (OGTT) at the Clinical Research Unit, SUNY Upstate Medical University. Venous blood samples are collected at -15, 0, 30, 60, 90, and 120 minutes relative to glucose ingestion. At time 0 minutes, participants consume a commercially prepared standard 75-gram glucose solution; youth participants receive 1.75 grams of glucose per kilogram of body weight, not exceeding 75 grams total. After the final blood collection at 120 minutes, participants are provided a snack and continue their study visit. Blood is collected in pre-chilled aprotinin/EDTA tubes and processed for analysis of

What is a clinical trial?

A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.

Is it safe to participate?

Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.

Will I be compensated?

Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.

Will I receive a placebo instead of treatment?

When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.

Can I leave a trial if I change my mind?

Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.

How long does a clinical trial last?

Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.