Interactive Roles of Cardiorespiratory Fitness and Adiposity on Glucose and Vascular Control After Physical Inactivity

Interactive Roles of Cardiorespiratory Fitness and Adiposity on Recovery of Impaired Glucose and Vascular Control After Physical Inactivity

The far-reaching negative health effects of the reduced physical activity (RPA) epidemic are often overlooked by the general population and health professionals. Short-term RPA induces cardiometabolic dysfunction, including impaired glucose control and vascular function, that may precede disease development. The impact of existing health status on RPA-induced cardiometabolic dysfunction and recovery of impaired glucose control following RPA is unexplored. Thus, the investigators' objectives are 1) to investigate the effect of existing health status (cardiorespiratory fitness and adiposity) on the recovery of impaired glucose control following a period of RPA and 2) to determine the role of vascular function as a mechanism of impaired glucose control. The investigators' final objective is to 3) expose undergraduate students to meritorious biomedical clinical research methods. The investigators have piloted the clinical research methods and analysis with undergraduate researcher associates and are well-prepared to complete this proposal. Preliminary data show that low cardiorespiratory fitness and/or high adiposity impair the recovery of glucose control following short-term RPA. Thus, the investigators aim to examine the interactive role of health status (cardiorespiratory fitness and adiposity) on the ability to recover impaired glucose control following short-term RPA. The investigators also seek to examine changes in vascular function as a mechanism of recovery of impaired glucose control following a return to normal PA. The investigators will recruit men and women with divergent health status (cardiorespiratory fitness and adiposity) to examine glucose control and vascular function during 7-d of normal PA, 7-d of RPA, and 7-d of resumption of normal RA. Continuous glucose monitoring and oral glucose tolerance tests will be performed to assess glucose control. Increases in vascular shear stress induced by passive leg movement and central arterial stiffness will be measured to assess vascular function.

Study Overview

• Status: Not yet recruiting
• Conditions: Metabolic Disorders; Physical Inactivity; Vascular Disease Risk
• Intervention / Treatment: Other: reduced physical activity

• Study Type: Interventional
• Enrollment (Estimated): 48
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Kevin Ballard, PhD; Phone Number: 513-529-9247; Email: ballarkd@miamioh.edu
• Study Contact Backup: Name: Paul Reidy, PhD; Email: reidypt@miamioh.edu

Study Locations

• United States
  • Ohio
    • Oxford, Ohio, United States, 45056
      • Phillips Hall

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Males and females 18 to 40 years of age.
• Ability to safely ride an electric scooter (e-scooter) for at least 10 minutes.
• Active (>7000 steps per day, walking > 1 mile a day outside)
• Stable body weight for at least 1 year
• aerobic fitness level, CRF is < 9 and >14 METS
• Visceral adipose tissue <130 cm2 or ≥130 cm2 for men and <100 cm2 or ≥100 cm for women

Exclusion Criteria:

• Any injury preventing them from exercising regularly at the time of the screening.
• Implantable defibrillator or pacemaker
• Active cancer
• Alcohol or drug abuse
• Use of an assistive walking device
• Presence of significant signs/symptoms of cardiovascular, metabolic, or pulmonary disease (determined from the American College of Sports Medicine (ACSM) Health History Questionnaire)
• Daily vitamin consumption of > 500mg per day during the study
• Acetaminophen or aspirin use during the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• 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: Reduced physical activity; We will recruit, screen, and enroll eligible participants (18-40y) across the following four groups: high CRF/low adiposity, high CRF/high adiposity; low CRF/low adiposity; low CRF/high adiposity. Each participant will undergo a three-week study. For the first week, participants will be instructed to maintain their normal level of physical activity. For the second week, participants' schedules will be examined, and strategies designed to reduce steps (by at least 2000 steps) and physical activity. To assist in reducing walking and increased sitting, participants will be given seated electric scooters to use whenever they normally walk. The scooters will be returned on the third week, and participants will be instructed to resume their normal physical activity. During the entire three weeks, participants will wear a continuous glucose monitor and a physical activity monitor.

Other: reduced physical activity; Each participant will undergo a three-week study. For the first week (day -7 to day 0), participants will be instructed to maintain their normal level of physical activity. For the second week (day 0 to day 7), the reduced physical activity (RPA) week, participants' schedules will be examined, and strategies designed to reduce steps (by at least 2000 steps) and physical activity (by taking elevators and short-cuts, etc.) by increasing sitting time >10%. To assist in reducing walking and increased sitting, participants will be given seated electric scooters to use whenever they normally walk. The scooters will be returned on the third week (day 7 to day 14), and participants will be instructed to resume their normal physical activity. During the entire three weeks, participants will wear a continuous glucose monitor (CGM) and a physical activity monitor (ActivPal).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in Daily Physical Activity	Accelerometers will be use to measure changes in daily physical activity during the three week study duration. Accelerometer data to be reported includes: daily number of steps, daily sitting time, daily stepping time, total sedentary time, and activity score.	3 weeks
Oral Glucose Tolerance Test (OGTT)	On the morning of each OGTT, participants will arrive in the lab following an 8-10 h fast. An indwelling intravenous catheter will be placed into a forearm vein. Baseline (0 min) blood samples will be collected into heparinized evacuated tubes following 15 min of seated rest. Participants will consume a volume of glucose tolerance beverage containing 1 gram of glucose/kg of lean body mass to control for expected differences in body and fat mass between individuals. Participants will remain rested in the reclined position for the duration of the OGTT. Blood samples will be collected at 30, 60, 90, and 120 min post drink. Heparinized blood samples will be utilized to assess blood glucose using the Contour Next blood glucose monitoring system.	Days 0, 7, and 14
Continuous Glucose Monitoring	Participants will wear CGM sensors for the duration of the study, with the first sensor being placed on day -7 and a second sensor replacing it on day 0. Data will be exported and quality-checked data will be imported into the IGlu Application in R Studio and analyzed using the following parameters: Night hours set from 10 PM to 7 AM; Time above (high) set to 140 mg/dL; Time above (low) set to 120 mg/dL; Time in range set to 70-120 mg/dL; Time below (high) set to 70 mg/dL; Time below (low) set to 54 mg/dL; Data reported using this software includes weekly and daily means, standard deviations (SD), coefficient of variations (CV), medians, time below range < 54 mg/dL (TBR <54), time below range < 70 mg/dL (TBR <70), time in range 70-120 mg/dL (TIR 70-120), time above range >120 mg/dL (TAR >120), time above range >140 mg/dL (TAR >140), mean amplitude of glycemic excursions (MAGE), and area under the curve (AUC).	3 weeks
Femoral Artery Blood Flow	Passive leg movement (PLM)-induced reactive hyperemia will be measured to assess peripheral vascular function. Briefly, the PLM technique involves passive movement of the leg to elicit a reactive hyperemic response measured by high-frequency ultrasonographic imaging. Diameter and blood velocity in the common femoral artery will be measured following 15 minutes of seated rest using a 5 to 12MHz multi-frequency linear array transducer connected to a high-resolution ultrasound. Arterial diameter and velocity will be recorded continuously for 60 seconds at baseline and 60 seconds during PLM. Femoral artery blood flow and shear rate (estimate of shear stress) will be calculated from arterial diameter and blood velocity measurements.	Days 0, 7, and 14

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fat Mass and Fat-Free Mass	Fat mass (kg) and fat-free mass (kg) will be determined using bioelectrical impedance and dual x-ray absorptiometry.	Days 0, 7, and 14
Height	Height (cm) will be determined using a wall-mounted stadiometer.	Days 0
Central Arterial Stiffness	Carotid-femoral pulse wave velocity will be measured following 10 min of rest to assess central arterial stiffness.	Days 0, 7, and 14
Central Arterial Blood Pressure	Pulse wave analysis will be measured following 10 min of rest to assess central arterial blood pressure.	Days 0, 7, and 14
Blood Lipids	A blood sample will be collected during fasted conditions on Days 0, 7, and 14 for determination of blood lipids (total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides).	Days 0, 7, and 14
Cardiorespiratory Fitness	On the screening day, participants will perform a Balke-graded exercise treadmill test to assess cardiorespiratory fitness. This test will be conducted on a treadmill and lasts between about 10 and 20 minutes. Heart rate, oxygen consumption, and rating of perceived exertion (RPE) will be monitored every minute during the test.	Day 0

Collaborators and Investigators

• Sponsor: Miami University

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2025
• Primary Completion (Estimated): June 30, 2028
• Study Completion (Estimated): June 30, 2029

Study Registration Dates

• First Submitted: February 7, 2025
• First Submitted That Met QC Criteria: February 18, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: February 18, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Keywords: physical activity; glucose control; vascular function
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Metabolic Diseases
• Other Study ID Numbers: 02290-1R15HL177798-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: IPD will not be shared.

Drug and device information, study documents

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