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CompletedNCT04812392Updated Mar 4, 2026

Physical Inactivity Impacts on Blood Vessel Health and Glucose Levels in an Aging Population

An interventional study of Continuous Glucose Monitoring System in Aging, Cardiovascular Diseases and Glucose Intolerance, sponsored by Leryn Reynolds. Completed at 1 site in United States. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-03-04.

Sponsored by Leryn Reynolds · Not applicable, Interventional, and Basic science

From the registry’s dates

  • Primary completion was Jan 2022, 4 years 8 months ago, and no results have been posted to the registry.
Phase
Not applicable
Study type
Interventional
Enrollment
20
Allocation
Not applicable
Ages
18 Years and older
Sex
All
01

Study summary

Physical inactivity is known to increase post meal blood sugar levels in young, active populations. However, how quickly this may occur in active, older adults is not clear. Further, the relationship between blood vessel health and blood sugar disturbances which occur to acute physical inactivity is not clear. It is unknown if impairments in blood vessel function precede increases in blood sugar levels that occurs with inactivity in an aging population. This study aims to determine if short term reductions in physical activity impair blood vessel health and blood glucose control to a greater extent in an aging population compared to a young population. The investigators hypothesize that 3 days of reduced physical activity will result in impaired blood vessel function and glycemic control in an aged population.

Read the detailed description

Subjects will undergo testing in 2 study phases separated by at least 2 weeks: 1) active phase: subjects will have post meal glucose levels measured across 3 days of participating in their normal exercise routines. Blood vessel health will also be measured via flow mediated dilation at the end of the 3 day monitoring period. 2) physically inactive phase: subjects will stop participating in exercise for 3 days while post meal glucose levels are measured. Blood vessel health will also be assessed on days 1, 3 of removal of exercise. The subject will need to come into the lab on these days of inactivity to have blood vessel health measured.

The study procedures are described below.

Continuous Glucose Monitoring The investigators would like to gain more information about how blood sugar levels change over the course of a day in a free living setting. To do this the investigators will use a continuous glucose monitoring system (CGMS). This system is what individuals with diabetes frequently use to monitor their glucose levels over the course of the day. Subjects will be asked to wear the CGMS for 3 consecutive, full days on 2 different occasions. This includes 3 days during their normal regular physical activity, then for 3 days following during the no exercise protocol. The CGMS is worn on the stomach, and it is a tiny glucose sensor which is inserted just under the skin. This device measures and records blood glucose values throughout the day. In addition, subjects will be asked to make at least four finger stick blood glucose readings taken with a standard glucose meter at different times each day and record these numbers on a log sheet. During the continuous glucose monitoring, subjects will need to consume the same type and quantity of foods at the same time each day (i.e. whatever the subjects consumes on day 1 of baseline testing, they need to eat that exact same food, volume of food and at the same time on days 1-3 of the study). Meals and snacks consumed are also entered into a paper-based diary.

Blood Vessel Health Measurement (Flow Mediated Dilation: FMD) Subjects will be asked to perform their normal exercise routines 12-16 hours prior to blood vessel health being measured in the active phase as well as prior to the first blood vessel health measurement in the inactive phase to control for the acute effects of exercise on blood vessel health. Blood vessel health will be measured at the end of the active phase in both groups of subjects. Further blood vessel health will be measured following 1, 3 days of being inactive in both groups of subjects. Blood flow to the leg will be measured by applying blood pressure cuffs around the ankle. Pre flow mediated dilation diameter and velocity are recorded for 3 minutes prior to a blood pressure cuff being inflated for 5 minutes. Following cuff deflation, a 2-minute diameter and velocity recording is collected.

02

Conditions studied

  • Aging
  • Cardiovascular Diseases
  • Glucose Intolerance

Keywords

  • diabetes
  • physical inactivity
  • vascular function
03

In context

Cardiovascular Diseases

4,904 studies on the registry are indexed under Cardiovascular Diseases; 919 are open to participants now.

This study's enrollment of 20 is below the median of 100 across 2,738 interventional studies indexed under Cardiovascular Diseases.

Browse Cardiovascular Diseases studies →

Lead sponsor

This is the only study on the registry with Leryn Reynolds as lead sponsor.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
Yes

Inclusion criteria

  1. 55 years and older, 18-40 years old
  2. Healthy, physically active, performing at least 90 min/week of physical activity
  3. Free of physical limitations that may interfere with alterations in daily physical activity levels

Exclusion criteria

Exclusion Criteria:

  1. Physician diagnosed metabolic disease, HIV, hepatitis, or tuberculosis.
  2. Body weight change of greater than 5% within the previous 2 months
  3. Smoking within the previous 2 months.
  4. Taking medications that alter blood glucose levels
05

Study design

Phase
Not applicable
Primary purpose
Basic science
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
20 participants (actual)

Study arms

  • Experimental
    Acute Physical Inactivity

    Subjects will undergo 3 days of reduced physical activity.

    Device: Continuous Glucose Monitoring System

Interventions

  • DeviceContinuous Glucose Monitoring System

    Subjects will wear a continuous glucose monitoring system for 3 days during the 3 day reduced physical activity phase.

06

What researchers measure

Primary outcomes

  1. Change in glycemic control during a reduced physical activity state

    The change in blood glucose levels measured following consumption of a meal will be assessed before inactivity and following 3 days of inactivity.

    Time frame: The change of blood glucose values from pre-inactivity and following 3 days of inactivity

07

Study locations

1 site
  • Old Dominion University
    Norfolk, Virginia 23508, United States
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Mar 4, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT04812392
Lead sponsor
Leryn Reynolds
Responsible party
Leryn Reynolds (Assistant Professor, Old Dominion University) — Sponsor-investigator
First posted
Mar 23, 2021
Start date
Apr 1, 2021
Primary completion
Jan 30, 2022
Completion
Jan 30, 2022
Last update
Mar 4, 2026

Study contacts

Leryn Reynolds, Ph.D.
principal investigator · Old Dominion University

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
Yes
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.

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