Exercise and Protein Efficiency in T2D (ADA)

Exercise Impact on Dietary Protein Efficiency in Older Adults With Type 2 Diabetes

In this randomized controlled trial, 30 older adults (aged> 65 years; 15 with T2D, 15 controls) will participate in a 12-week progressive exercise training program. They will undergo pre- and post-testing that includes body composition measures; oral glucose tolerance testing; cardiovascular fitness and muscle performance testing; dietary protein efficiency assessed using the indicator amino acid oxidation (IAAO) method; and a gut microbiota trial. The dietary protein efficiency trial will include repeated ingestion of crystallized amino acids (drink) containing stable isotopes, urine samples, and breath samples. The gut microbiome trial will consist of a single ingestion of a Mediterranean-based modeled meal enriched with 13C-phenylalanine (in the drink) and repeated blood draws. Participants will also be asked to give a fecal sample after the gut microbiome trial.

Study Overview

• Status: Recruiting
• Conditions: Type 2 Diabetes; Control Condition
• Intervention / Treatment: Other: 12 week progressive exercise training

Detailed Description

1. Enrollment, Informed Consent, and Screening Questionnaires: Prior to study enrollment, participants will be asked to read a digital copy of an informed consent document provided using the e-Consent framework through the Research Electronic Data Capture (REDCap) system. Should participants have any questions about the study after reading the document, they will be encouraged to contact the research team prior to providing informed consent. Upon providing informed consent, participants will receive an email containing questionnaires designed to assess study eligibility via REDCap. Specifically, participants will be asked to complete a health and medical history questionnaire, physical activity readiness questionnaire (PARQ), International Physical Activity Questionnaire Long Form (IPAQ), and Godin-Shephard Leisure-Time Physical Activity Questionnaire (LTPAQ). Information from the questionnaires will be used to assess exclusion criteria, and the IPAQ will be used to assess baseline habitual activity level. Upon completion of these questionnaires, the research team will review the responses and determine eligibility.
2. Preliminary Testing Day 1:

2.1 Preparation: Participants will arrive for the preliminary testing session after an overnight fast (~10 h no caloric foods/beverages consumed) and having refrained from exercise for the 72 h prior.

3.2 Cardiorespiratory fitness assessment: Peak aerobic capacity and maximum heart rate (HR) will be estimated using a submaximal graded stationary bicycle exercise test. Briefly, participants will pedal for 3 minutes at a resistance of 0kg, maintaining a cadence of 50 as a warm-up. Then, the investigators will have the participant pedal for 3-4 minutes, or until a steady state is reached, at 0.5kg, maintaining the same cadence. Resistance is increased every 3-4 minutes until the participant reaches 85% of age-predicted maximal heart rate (220-age).

3.3 Muscle Performance (1RM and power Testing): maximum strength will be assessed using a 10-repetition max (10-RM) on a leg extension, leg press, leg curl, chest press, shoulder press, seated pulldown, and seated row machines. Following a 5-minute warm-up on a stationary bike at a self-selected resistance and speed, participants will perform a set of 8-10 reps at around 50% of what they think they can lift 10 times. 1-2 minutes of rest will be given between each try. The next set will be around 90% of what the participant believes they can lift ten times. investigators will gradually increase the weight by 2.5-5.0% at a time until the participant can no longer lift it. A two-minute rest will be provided between the maximum number of attempts and between exercises.

3.3.5 The HUMAC NORM Isokinetic Dynamometer (CSMi, Stoughton, Massachusetts) will be used to assess peak torque, average workload, and average power in concentric tests and maximal voluntary contraction (MVC). Each participant will be seated upright, with the knee bent. The shank of the dominant leg will be secured to a padded, rigid metal bar using a Velcro strap. With standardized verbal encouragement, participants will perform brief maximal voluntary isometric contractions (MVC), separated by at least 60 seconds of rest, to determine maximal knee extension torque. Maximal power of the knee extensor muscles will be obtained at several test velocities using 2 sets of 4 maximal isokinetic knee extensions, including at a velocity of 60 deg/s. Strong verbal encouragement will be provided to kick as hard and as fast as possible throughout the full range of motion for each velocity. Participants will rest for at least 60 seconds after each set of 4 contractions to minimize muscle fatigue during the power assessment.

4. Preliminary testing day 3: Dietary Efficiency trial 4.1 Preparations: 3 days prior to the trial, participants will receive 3 days' worth of standardized meals and be instructed to prepare meals based on the manufacturer's instructions. Participants will arrive for the preliminary testing session after an overnight fast (~10 hours, no caloric foods/beverages consumed) and after refraining from exercise for the 72 hours prior.

5.2 Blood Collection: An intravenous catheter will be placed in a hand or arm vein for repeat blood sampling. Blood samples will be collected at 10 time points (-30, 0, 30, 60, 90, 120, 150, 180, 240, and 300 minutes) during each gut microbiome trial (pre- and post-training).

5.3 Mediterranean-based modeled meal: At time point 0, participants will be asked to ingest ~20g of protein enriched with L-[ring- 13C6] Phenylalanine to ~30 MPE. The amino acid and fat composition of this meal will be modeled based on ~3.05 oz of salmon filet.

6. Fecal Collection A fecal sample collection kit will be provided to participants, and they will be asked to collect the first stool produced after the postprandial gut microbiota tracer trial (5.0). Participants will be asked to adhere to a three-day controlled diet prior to each of 2 fecal collections (1x pre-testing, 1x post-testing), and samples will be delivered to the lab at their next study visit.

7.0 Exercise Training: 7.1 Strength Training: On strength training days, participants will warm up on a stationary bike for 5 minutes before each training session. The training session will consist of 1-3 sets on the leg press, leg extension, and leg curl machines. In addition, participants will be asked to perform upper-body exercises on guided machines (seated chest press, seated shoulder press, seated row) on alternating training days. All sessions will be separated by 2-3 days. Training intensity will be progressive and based on individual comfort levels. During the first week of training (week 0), the training intensity will be gradually increased from ~60% 1 Repetition Max (1RM) (10-15 repetitions) to ~70% 1RM (10-12 repetitions).

7.2 Endurance training: For aerobic-based training, supervised exercise sessions will occur on a stationary bike. Exercise intensity will be controlled by heart rate (HR) and Rate of Perceived Exertion (RPE) using Borg's original scale (6-20 points). Exercise intensity will be progressive: weeks 1-3 will be 50-60% HR for 30 minutes; weeks 4-6, 50-60% for 40 minutes; weeks 7-9, 60-70% for 50 minutes; weeks 10-12, 60-70% for 60 minutes.

8. Psychological Evaluation During each in-person exercise day, participants will be evaluated using several psychological well-being questionnaires. The International Personality Item Pool (IPIP-50) is a 50-item assessment of the Five-Factor Model (Openness to Experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism/Emotional Stability). Additionally, the PRETIE-Q is a 16-item questionnaire designed to assess personal preferences for exercise intensity and perceived tolerance for it. The Dispositional Resilience Scale (DRS-15) will be used to assess participants' resilience, and the Hospital Anxiety and Depression Scale (HADS), a 14-item instrument used to assess the severity of anxiety and depressive symptoms in the past 7 days. The option to do these electronically or on paper will be given.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Nicholas Burd (Professor), PhD; Phone Number: 2172440970; Email: naburd@illinois.edu
• Study Contact Backup: Name: Gena Irwin (Research Assistant), M.S; Phone Number: 3608883281; Email: genai2@illinois.edu

Study Locations

• United States
  • Illinois
    • Urbana, Illinois, United States, 61801
      • Recruiting
      • Freer Hall - University of Illinois
      • Contact: Nicholas Burd (Professor), PhD; Phone Number: 2172440970; Email: naburd@illinois.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• At least 65 years old
• Body mass index: 25-40 kg/m^2
• Female: Waist to hip ratio >0.8
• Male: Waist to hip ratio >1.0
• Free from structured exercise during the prior 6 months (mo) weight stable for the prior 6 months

T2D group:

-Diagnosed by a physician with elevated glycosylated hemoglobin (HbA1c) >6.5%

Control group:

-Normoglycemic with HbA1c levels not exceeding 5.6% and fasting blood glucose levels below or equal to 99 mg/dL (5.5mmol)

Exclusion Criteria:

• Uncontrolled diabetes (evidence of HbA1c > 10%, prescription of insulin)
• Diagnoses of diabetic neuropathy or failing diabetic neuropathy screening
• Statins
• Peripheral edema Consumption of ergogenic-levels of dietary supplements that may affect muscle mass (e.g., creatine, HMB), insulin-like substances, or anabolic/catabolic pro-hormones (e.g., DHEA) within 6 weeks prior to participation.
• Untreated hypothyroidism, epilepsy, medications that affect vasoactivity, possibility of pregnancy, and any neurological, cardiovascular, or musculoskeletal disease that precludes exercise testing.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Non-Diabetic; Non-diabetic control group. Will be assigned to all pre-/post-testing and complete the 12-week intervention period.	Other: 12 week progressive exercise training; moderate - to - vigorous aerobic and strength-based exercise training will be performed 2-3 times per week for 12 weeks. Strength Training consists of a 5-minute warm-up on a stationary bike, followed by 1-3 sets on the leg press, leg extension, and leg curl machines. In addition, participants will preform upper body exercises on guided motion machines (seated chest press, shoulder press, seated rows) on alternate training days. Training intensity will gradually increase on each participants comfort level. Endurance training will be performed on a stationary bike. Exercise intensity will be controlled by heart rate and rate of perceived exertion (RPE) using the Borg's original scale (6-20 points). Weeks 1--3 will be at 50-60% of max heart rate for 30 minutes; weeks 4-6 will be at 50-60% of max heart rate for 40 minutes; weeks 7-9 will be 60-70% of max heart rate for 50 minutes; and weeks 10-12 will be at 60-70% of max heart rate for 60 minutes.; Other Names: 12-week progressive training
Experimental: Diabetic group; Diagnosed diabetic group. Will complete all pre- and post-testing and the 12-week intervention period.	Other: 12 week progressive exercise training; moderate - to - vigorous aerobic and strength-based exercise training will be performed 2-3 times per week for 12 weeks. Strength Training consists of a 5-minute warm-up on a stationary bike, followed by 1-3 sets on the leg press, leg extension, and leg curl machines. In addition, participants will preform upper body exercises on guided motion machines (seated chest press, shoulder press, seated rows) on alternate training days. Training intensity will gradually increase on each participants comfort level. Endurance training will be performed on a stationary bike. Exercise intensity will be controlled by heart rate and rate of perceived exertion (RPE) using the Borg's original scale (6-20 points). Weeks 1--3 will be at 50-60% of max heart rate for 30 minutes; weeks 4-6 will be at 50-60% of max heart rate for 40 minutes; weeks 7-9 will be 60-70% of max heart rate for 50 minutes; and weeks 10-12 will be at 60-70% of max heart rate for 60 minutes.; Other Names: 12-week progressive training

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Define how exercise modifies protein efficiency in T2D	Define how exercise modifies protein efficiency by assessing whole-body net protein balance via amino acid oxidation rates in response to protein intake of 1.0 g protein/kg/d. We expect to observe elevated baseline (pre-training) rates of oxidative excretion in aging T2D compared with CON. Following 12 weeks of exercise, both groups will improve their whole-body net protein balance, (indicative of lower oxidation rates), but the largest effects will be observed in the T2D vs CON group	From enrollment to end of 12-week intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Impact of training on gut microbiota on derived metabolites	Exercise training in older adults with T2D shifts aromatic amino acid (ArAA) metabolism toward beneficial aryl-lactates (e.g., PLA) and away from harmful aryl-acetates (e.g., PAG). Pre- and post-exercise intervention conversion of phenylalanine will be assessed with acute labeled 13C6 Phe ingestion. Downstream labeled Phe metabolites (ng/mL) will be quantified in blood serum over 5 hours post-labeled Phe intake.	from pretesting to post testing following a 12-week exercise intervention

Collaborators and Investigators

• Sponsor: University of Illinois at Urbana-Champaign
• Collaborators: American Diabetes Association

Study record dates

Study Major Dates

• Study Start (Actual): February 9, 2026
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): July 1, 2028

Study Registration Dates

• First Submitted: December 1, 2025
• First Submitted That Met QC Criteria: March 12, 2026
• First Posted (Actual): March 17, 2026

Study Record Updates

• Last Update Posted (Actual): April 29, 2026
• Last Update Submitted That Met QC Criteria: April 27, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Obesity; Type 2 Diabetes; Exercise Intervention; Protein Metabolism
• Additional Relevant MeSH Terms: Endocrine System Diseases; Nutrition Disorders; Metabolic Diseases; Overnutrition; Body Weight; Glucose Metabolism Disorders; Diabetes Mellitus; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity; Diabetes Mellitus, Type 2
• Other Study ID Numbers: IRB25-0851; 7-25-ICTSAD-418 (Other Grant/Funding Number: American Diabetes Association)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Because it is not intended for publication in any ICMJE journal.

Drug and device information, study documents

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