Exercise Training and Metabolic Flexibility in Prediabetes

The Effect of an Exercise Training Program on Metabolic Flexibility in Older Adults With Prediabetes

The purpose of the study is to determine if a 6-week exercise training program promotes exercise-induced metabolic flexibility, that is, the ability to switch fuel sources for energy, in older prediabetic adults.

Study Overview

• Status: Terminated
• Conditions: Sedentary Lifestyle; PreDiabetes
• Intervention / Treatment: Behavioral: 6-week exercise training program; Behavioral: Standardized isoenergetic high fat diet

Detailed Description

This is an investigator initiated single group intervention trial. All participants will receive a 6-week exercise training program with testing occurring before and following the training program. Participants will be provided with 3 days of a high fat diet prior to each of the three testing sessions at the Clinical Research Unit. All who agree to participate will undergo the same intervention.

The goal of this proposal is to study the impact of a 6-week moderate intensity walking training program on exercise induced lipid metabolic flexibility in older adults with prediabetes. Study Investigators will seek to determine if exercise induced lipid oxidation following a high fat diet is increased in trained individuals relative to their baseline.

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • North Carolina
    • Winston-Salem, North Carolina, United States, 27105
      • Department of Health and Exercise Science Clinical Research Center
    • Winston-Salem, North Carolina, United States, 27157
      • Wake Forest Baptist Medical Center Clinical Research Unit

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 60 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• ≥60 years of age
• Sedentary prior to the start of the training program (self-reported: less than 30 minutes of exercise for no more than 1 day a week)
• Prediabetes (measured at first screening: HbA1c = 5.7-6.5%)
• Must be able to pick-up and consume study provided foods
• Willingness to provide informed consent and participate in the intervention
• Must obtain transportation to visits and intervention training sessions
• No contraindications for involvement in a moderate exercise training program or exercise testing procedures by self-report

Exclusion Criteria:

• Self-reported diagnosis of a metabolic or chronic disease such as cardiovascular disease, diabetes, Chronic Obstructive Pulmonary Disease, or movement disorders such as Parkinson's disease, Ataxia, Huntington's Disease
• Current or recent (<12 months) treatment for cancer
• Body Mass Index <18.5 or >/30.0 kg/m2
• Tobacco users
• Febrile or chronic infection within study period
• Aversion to testing procedures
• Hypertension, hyperthyroidism, hypothyroidism
• Unwilling to abstain from ingesting caffeine during study testing periods
• Unwilling to withhold medications that affect metabolic rate during testing periods
• Physically active (>30 minutes per day on more than 1 day per week)
• ECGs that indicate cardiac injury or contraindications to treadmill testing
• Allergic or intolerant to any study-provided foods

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Exercise Training Group; All 20 participants will be assigned to this arm. These individuals will participate in 6 weeks of a moderate supervised aerobic exercise training program.

Behavioral: 6-week exercise training program; Participants will walk at 50% Heart Rate Reserve (HRR) 3 to 5 days per week for 6 weeks at the Department of Health and Exercise Science Clinical Research Center under the supervision of study staff.; Behavioral: Standardized isoenergetic high fat diet; Prior to the submaximal exercise testing visits, all participants will be provided with 3 days of a standardized isoenergetic high fat diet (20% of kcals from carbohydrate, 65% fat; 15% protein) to promote lipid oxidation. The meals will be prepared and provided by the Clinical Research Unit of Wake Forest Baptist Health. Participants will pick up 3 days' worth of food and snacks 4 days prior the testing visit. For the 3 days leading up to the visit, participants will eat the provided foods and complete a compliance assessment.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Metabolic Rate-Baseline	Metabolic rate will be measured by gas exchange using indirect calorimeter. For the first (baseline test) and second (follow up test 1) time we monitor gas exchange, participants will exercise for 20 minutes at a workload that elicits 50% of maximal oxygen consumption as determined by Graded Exercise Test #1 done before the exercise training program. The third time (follow up test 2), participants will exercise for 20 minutes at a workload that elicits 50% of oxygen consumption as determined by Graded Exercise Test #2 done after the exercise training program.	Baseline
Metabolic Rate_6 weeks after exercise training program	Metabolic rate will be measured by gas exchange using indirect calorimeter. For the first (baseline test) and second (follow up test 1) time we monitor gas exchange, participants will exercise for 20 minutes at a workload that elicits 50% of maximal oxygen consumption as determined by Graded Exercise Test #1 done before the exercise training program. The third time (follow up test 2), participants will exercise for 20 minutes at a workload that elicits 50% of oxygen consumption as determined by Graded Exercise Test #2 done after the exercise training program.	6 weeks exercise training program
Blood collection_lactate Baseline	At baseline and follow-up testing visits, 6 blood samples at each visit (times 0, 5, 10, 15, 20, and 50) will be obtained for measures of lactate. Blood draws will happen as gas exchange is being measured. 1 tsp of blood will be taken through a catheter at each time point.	Baseline
Blood collection_lactate follow up 1	At baseline and follow-up testing visits, 6 blood samples at each visit (times 0, 5, 10, 15, 20, and 50) will be obtained for measures of lactate. Blood draws will happen as gas exchange is being measured. 1 tsp of blood will be taken through a catheter at each time point.	6 weeks exercise training program
Blood collection_lactate follow up 2	At baseline and follow-up testing visits, 6 blood samples at each visit (times 0, 5, 10, 15, 20, and 50) will be obtained for measures of lactate. Blood draws will happen as gas exchange is being measured. 1 tsp of blood will be taken through a catheter at each time point.	3-10 days following Follow-Up Test 1
Blood collection_glucose baseline	At baseline and follow-up testing visits, 6 blood samples at each visit (times 0, 5, 10, 15, 20, and 50) will be obtained for measures of glucose. Blood draws will happen as gas exchange is being measured. 1 tsp of blood will be taken through a catheter at each time point.	Baseline
Blood collection_glucose follow up 1	At baseline and follow-up testing visits, 6 blood samples at each visit (times 0, 5, 10, 15, 20, and 50) will be obtained for measures of glucose. Blood draws will happen as gas exchange is being measured. 1 tsp of blood will be taken through a catheter at each time point.	6 weeks exercise training program
Blood collection_glucose follow up 2	At baseline and follow-up testing visits, 6 blood samples at each visit (times 0, 5, 10, 15, 20, and 50) will be obtained for measures of glucose. Blood draws will happen as gas exchange is being measured. 1 tsp of blood will be taken through a catheter at each time point.	3-10 days following Follow-Up Test 1
Blood collection_nonesterified fatty acids	At baseline and follow-up testing visits, 6 blood samples at each visit (times 0, 5, 10, 15, 20, and 50) will be obtained for measures of nonesterified fatty acids. Blood draws will happen as gas exchange is being measured. 1 tsp of blood will be taken through a catheter at each time point.	Baseline
Blood collection_nonesterified fatty acids follow up 1	At baseline and follow-up testing visits, 6 blood samples at each visit (times 0, 5, 10, 15, 20, and 50) will be obtained for measures of nonesterified fatty acids. Blood draws will happen as gas exchange is being measured. 1 tsp of blood will be taken through a catheter at each time point.	6 weeks exercise training program
Blood collection_nonesterified fatty acids follow up 2	At baseline and follow-up testing visits, 6 blood samples at each visit (times 0, 5, 10, 15, 20, and 50) will be obtained for measures of nonesterified fatty acids. Blood draws will happen as gas exchange is being measured. 1 tsp of blood will be taken through a catheter at each time point.	3-10 days following Follow-Up Test 1
Blood collection_insulin	At baseline and follow-up testing visits, 6 blood samples at each visit (times 0, 5, 10, 15, 20, and 50) will be obtained for measures of insulin. Blood draws will happen as gas exchange is being measured. 1 tsp of blood will be taken through a catheter at each time point.	Baseline
Blood collection_insulin follow up 1	At baseline and follow-up testing visits, 6 blood samples at each visit (times 0, 5, 10, 15, 20, and 50) will be obtained for measures of insulin. Blood draws will happen as gas exchange is being measured. 1 tsp of blood will be taken through a catheter at each time point.	6 weeks exercise training program
Blood collection_insulin follow up 2	At baseline and follow-up testing visits, 6 blood samples at each visit (times 0, 5, 10, 15, 20, and 50) will be obtained for measures of insulin. Blood draws will happen as gas exchange is being measured. 1 tsp of blood will be taken through a catheter at each time point.	3-10 days following Follow-Up Test 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
VO2 peak	The gold standard for assessing cardiovascular fitness is exercise capacity as determined from peak volume of oxygen consumption (VO2peak) and treadmill time during a graded exercise test. A physician supervised, individualized ramp treadmill protocol will be performed on each participant. In this protocol, participants walk at a brisk pace with the speed based on their comfort and fitness. For lower fit individuals, the grade will be increased at a rate of 1%/minute, and for higher fit individuals, the grade will be increased at a rate of 2%/minute. The treadmill test will be performed according to guidelines set by the American College of Sports Medicine (ACSM, 2014), to evaluate the subject's cardiovascular response to exercise.	Baseline (Pre-exercise training)
VO2 peak	The gold standard for assessing cardiovascular fitness is exercise capacity as determined from peak volume of oxygen consumption (VO2peak) and treadmill time during a graded exercise test. A physician supervised, individualized ramp treadmill protocol will be performed on each participant. In this protocol, participants walk at a brisk pace with the speed based on their comfort and fitness. For lower fit individuals, the grade will be increased at a rate of 1%/minute, and for higher fit individuals, the grade will be increased at a rate of 2%/minute. The treadmill test will be performed according to guidelines set by the American College of Sports Medicine (ACSM, 2014), to evaluate the subject's cardiovascular response to exercise.	6 weeks (Post exercise training)

Collaborators and Investigators

• Sponsor: Wake Forest University Health Sciences
• Investigators: Principal Investigator: Gary Miller, PhD, Wake Forest Department of Health and Exercise Science

Study record dates

Study Major Dates

• Study Start (Actual): October 29, 2019
• Primary Completion (Actual): August 17, 2022
• Study Completion (Actual): August 17, 2022

Study Registration Dates

• First Submitted: August 7, 2019
• First Submitted That Met QC Criteria: August 8, 2019
• First Posted (Actual): August 9, 2019

Study Record Updates

• Last Update Posted (Actual): November 7, 2023
• Last Update Submitted That Met QC Criteria: November 1, 2023
• Last Verified: June 1, 2023

More Information

Terms related to this study

• Keywords: Metabolic Flexibility; Exercise Induced Metabolic Flexibility
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Endocrine System Diseases; Diabetes Mellitus; Hyperglycemia; Prediabetic State; Glucose Intolerance
• Other Study ID Numbers: IRB00058517; 10000441 (Translational Science Center)

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