The Influence of Physical Activity on the Gut Microbiome of Pre-Diabetic Adults

The present study is a 100-participant randomized controlled 2-arm parallel trial that employs a metagenomic approach to examine how 8 weeks of supervised moderate-intensity treadmill walking exercise (MWE) for 30-45 min 3 times/week alters the gut microbiome, serum short chain fatty acids, and the cardiometabolic profile, body weight, and body composition of individuals 30-64 years old who have overweight or obesity and have prediabetes.

Study Overview

• Status: Completed
• Conditions: Obesity; Overweight; Type 2 Diabetes Mellitus; PreDiabetes; Type 2 Diabetes; Type 2 Diabetes Mellitus in Obese; Overweight and Obesity
• Intervention / Treatment: Behavioral: Physical Activity Intervention

Detailed Description

All eligible and consented participants will complete a 3-week run-in phase during which baseline outcome assessments will be performed. During run-in weeks 1 and 2, participants will wear a Fitbit Inspire 2 smartwatch and complete three unannounced dietary recalls. During the run-in week 3 (see table below), participants will consume their 3-day standardized meal plan on days three through five, obtain a fecal sample, complete a study questionnaire, and complete a study assessment visit. To quantify compliance with the 3-day meal plan, participants will be provided with a paper checklist of all foods to be consumed, and will be asked to indicate which foods were consumed and to document any deviation. The study assessment visit will include a fasting blood draw (at baseline and week eight only), blood pressure in triplicate, weight measure and body fat assessment in duplicate, and a saliva sample.

• Study Type: Interventional
• Enrollment (Actual): 77
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Minnesota
    • Minneapolis, Minnesota, United States, 55455
      • University of Minnesota

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 30 years to 64 years (Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Classified as overweight or obese with BMI 25.0-39.9 kg/m2.
• Documentation* of a prediabetes diagnosis within one year of enrollment by physician or primary care provider based on lab tests showing a fasted blood glucose of 100-125 mg/dL, a 2-hour oral glucose tolerance test of 140-199 mg/dL, or an HbA1c level of 5.7%-6.4%76; OR a study screening lab value of HbA1C within the afore mentioned range.
• Currently engaged in <100 min/week of physical activity - confirmed by questionnaire.
• No exercise contraindications as assessed by the Physical Activity Readiness Questionnaire (PAR-Q)78-this Questionnaire involves seven "yes" or "no" questions regarding an individual's health status, with answering "yes" to any one of these questions requiring a prospective participant to acquire a written doctor's note stating they can safely participate in the trial's exercise intervention.
• No self-reported physical/mental disabilities or gastrointestinal conditions.
• No antibiotic usage within the last 45 days.
• Stable weight over the last 6 months (<10% change).
• Not currently pregnant, planning to become pregnant, or currently breastfeeding.

• Willing to maintain current dietary and exercise habits, aside from any changes to be made per the study exercise protocol.

  • Note: Documentation can include either a print out or screen shot of the lab value illustrating eligibility, along with the date of the test and the participant's name. If a hard copy is provided, the date and name will be redacted.

Exclusion Criteria:

• Self-reported use of metformin and/or other medications that could interfere with the primary outcome.
• History of bariatric surgery or a history of other medical interventions that would interfere with the primary outcome.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental Group; Participants in this group will complete the physical activity intervention.	Behavioral: Physical Activity Intervention; Three walking sessions/week for a total of 8 weeks (24 total sessions) - Walking sessions will either take place on new commercial treadmills in the Epidemiology Clinical Research Center or remotely at or around a participant's home. Regardless of the walking location, walking sessions will be 30 min in duration during intervention weeks 1 through 4 and a minimum of 45 min each during intervention weeks 5 through 8.
No Intervention: Control Group; Participants in this group will be asked to maintain their normal level of physical activity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Shannon Index (Unitless)	Changes to the gut microbiome will be assessed via metagenomic sequencing, from pre- to post-intervention. The Shannon Index-a measure of microbial community diversity-will be the primary indicator for changes in gut microbiota composition, and will be assessed at baseline, and following the 4th and 8th weeks. Index values are unitless and range from 0 to 1. Lower values indicate more diversity while higher values indicate less diversity. Outcome will be reported at baseline, 4 weeks, and 8 weeks and as the change from baseline to 4 weeks and baseline to 8 weeks.	8 weeks
Change in Serum Short Chain Fatty Acids (SCFA)	Participants will undergo fasted blood draws to assess serum SCFA levels. This work will be performed using the Metabolon pipeline. Outcome is reported as the sum of the serum concentrations of acetate, propionate, and butyrate in Z-score units. We report the Week 8 means and standard errors from a linear model adjusted for the Week 0 (baseline) values. The original units are reported in ng/mL and the final results are reported as standardized z-scores in which each value subtracts the mean and the difference is divided by the standard deviation. Higher values represent higher levels of SCFA which is considered better. The scale is in standard deviation units. A value of 0 = the population mean.	8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
High-density Lipoprotein Cholesterol (HDL-C)	High-density lipoprotein cholesterol (HDL-C) will be measured using standard laboratory test and report in units of mg/dl. We report the Week 8 means and standard errors from a linear model adjusted for the Week 0 (baseline) values.	8 weeks
Triglycerides	Blood triglycerides will be measured using a standard laboratory test and reported in units of mg/dl. We report the Week 8 means and standard errors from a linear model adjusted for the Week 0 (baseline) values.	8 weeks
Fasting Insulin	Fasting insulin will be measured by laboratory test and reported in units of pm/ml. We report the Week 8 means and standard errors from a linear model adjusted for the Week 0 (baseline) values.	8 weeks
Fasting Glucose	Fasting glucose will be measured by standard laboratory test and reported in units of mg/dl. We report the Week 8 means and standard errors from a linear model adjusted for the Week 0 (baseline) values.	8 weeks
C-reactive Protein (CRP)	C-reactive protein (CRP) will be measured by laboratory test and reported in units of mg/l. We report the Week 8 means and standard errors from a linear model adjusted for the Week 0 (baseline) values.	8 weeks
Resting Systolic Blood Pressure (BP)	Resting systolic blood pressure will be reported in units of mmHg. We report the Week 8 means and standard errors from a linear model adjusted for the Week 0 (baseline) values.	8 weeks
Body Composition	Body composition will be analyzed using bioelectrical impedance. Outcome will be reported as percent body fat. We report the Week 8 means and standard errors from a linear model adjusted for the Week 0 (baseline) values.	8 weeks
Cardiometabolic Risk Score (CMR)	The Cardiometabolic Risk Score (CMR) is the mean Z-score across systolic blood pressure, glucose, insulin, HDL, % body fat, and triglycerides. We report the Week 8 means and standard errors from a linear model adjusted for the Week 0 (baseline) values. The final results are reported as standardized z-scores in which each value subtracts the mean and the difference is divided by the standard deviation. Higher values represent higher levels of cardiometabolic risk which is considered worse. The scale is in standard deviation units. A value of 0 = the population mean.	8 weeks

Collaborators and Investigators

• Sponsor: University of Minnesota
• Investigators: Principal Investigator: Ryan Demmer, PhD, University of Minnesota

Study record dates

Study Major Dates

• Study Start (Actual): July 29, 2021
• Primary Completion (Actual): November 30, 2023
• Study Completion (Actual): November 30, 2023

Study Registration Dates

• First Submitted: June 11, 2021
• First Submitted That Met QC Criteria: June 11, 2021
• First Posted (Actual): June 18, 2021

Study Record Updates

• Last Update Posted (Actual): June 13, 2025
• Last Update Submitted That Met QC Criteria: June 11, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Keywords: Physical Activity; Microbiome
• Additional Relevant MeSH Terms: Endocrine System Diseases; Nutrition Disorders; Metabolic Diseases; Overnutrition; Body Weight; Glucose Metabolism Disorders; Overweight; Obesity; Diabetes Mellitus, Type 2; Diabetes Mellitus; Prediabetic State
• Other Study ID Numbers: STUDY00009136

Drug and device information, study documents

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