Effects of Acute Exercise Intensity on Cerebral Blood Flow and Cognitive Function in Older Adults

November 28, 2023 updated by: Jason Allen, University of Virginia
This study will analyze the influence of acute bout exercise intensities (continuous moderate and HIIT) on middle cerebral artery velocity (MCAv) to identify which intensity elicits the greatest increase in CBF in older adults (65+ yrs). Additionally, this study will help verify positive correlations between MCAv and cognitive function. These findings are important in determining the optimal exercise prescription for increased resilience against the age-related cognitive degradation.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

With an increasingly aging population, it is paramount that we further understand the changes that occur during aging, especially those which contribute to cognitive decline. Evidence shows that cognitive function is closely linked to brain blood flow. When comparing cerebral blood flow (CBF) between old and young individuals, older adults appear to have lower baseline levels of CBF. One of the principle determinants of CBF is CO2. Since exercise results in rises in CO2 production, changes in CBF can be monitored. Older adults appear to have diminished changes in CBF compared to younger individuals during moderate intensity exercise. This then leads to the idea that older adults may need a greater exercise stimulus (i.e. HIIT) to see these changes in CBF. However, the effects of HIIT on CBF in older adults is largely unstudied.

Purpose: To analyze the acute influence of HIIT on middle cerebral artery velocity (MCAv) in older adults, and to verify the positive association between MCAv and cognitive function.

Experimental Design: Recruiting 16 healthy adults age 65 and older. The study will require each participant to report to 4 visits: a screening visit, a control, a moderate intensity exercise bout, and a high intensity exercise bout. The order of the experimental visits will be randomized to each subject, and exercise bouts will be work-matched. During the experimental visits, MCAv, end-tidal CO2, MAP, and HR will be measured continuously. Vascular measures such as pulse wave analysis and pulse wave velocity will be taken pre- and post-exercise. Additionally, blood flow through the internal carotid artery and cognitive measures (n-back test) will be measured and administered pre-exercise, and at 15 mins, 30 mins, and 45 mins post-exercise. A two-way repeated measures ANOVA will be used to determine significant differences for time (pre vs. post measures) x condition (control/moderate/HIIT).

Results: In the process of collecting data.

Implications: If the study is successful in its findings, this could change how exercise is prescribed to older adults. It could also lead to the question regarding if a greater exercise stimulus (i.e. SIT) may be even more beneficial for these individuals.

Study Type

Interventional

Enrollment (Actual)

13

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Virginia
      • Charlottesville, Virginia, United States, 22903
        • University of Virginia; Kinesiology Labs

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

65 years and older (Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • 65+ years of age
  • Comfortable with experiencing exercise-induced fatigue
  • Willingness and ability to comply with scheduled visits and study procedures
  • Able to provide consent on their own behalf
  • Type 2 Diabetics accepted

Exclusion Criteria:

  • Competitive athlete (Recreationally active is okay but no more than 3 days/week of structured exercise)
  • VO2max below 18 ml/kg/min in men, 15ml/kg/min in women (minimum thresholds for independent living seniors)
  • Inability of study staff to acquire signal from the MCA using TCD
  • Diagnosis of mild cognitive impairment, Parkinson's Disease, Alzheimer's Disease, multiple sclerosis, or psychiatric illness (unless mild depression or anxiety)
  • History of brain damage/stroke/concussions
  • Cardiovascular Disease, Pulmonary Disease, or dependence of supplemental O2
  • Type 2 Diabetics who aren't cleared by the study physician during the first screening visit (HbA1C > 8.5%)
  • Neuromuscular or musculoskeletal dysfunctions impairing one from cycling
  • Changes in vasoactive medication dose or quantity, recently prior to or during the study time course, or inability to maintain regular timed ingestion of vasoactive medication
  • Currently involved in Estrogen or Testosterone Replacement Therapy
  • Unable to abstain from food consumption (3hrs), caffeine/alcohol consumption (12hrs), and vigorous exercise (24hrs) prior to experimental procedures

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Control
Other: Control
In this intervention placebo, subjects will lay down on a flat, soft surface for 30 minutes in a dimly light room. They will not be allowed to use any electronic devices or read during this time to avoid potentially influencing continuous data recording.
Other Names:
  • Rest
Experimental: Acute bout of Continuous Moderate Intensity Exercise
Other: Acute bout of Continuous Moderate Intensity Exercise
In this experimental intervention subjects will cycle continuously at moderate intensity (VO2 corresponding to lactate threshold) until a 200 kcal equivalent energy expenditure is reached.
Experimental: Acute bout of High Intensity Interval Training (HIIT)
Other: Acute bout of High Intensity Interval Training
In this experimental invention subjects will alternate between 1 minute of high intensity cycling (watts corresponding to 85% VO2peak) and 1 minute of low intensity cycling (watts corresponding to 35-40% VO2peak) until a 200 kcal equivalent energy expenditure is reached.
Other Names:
  • HIIT

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Middle Cerebral Artery Velocity (MCAv)
Time Frame: Measured continuously over the course of each experimental session (i.e. 2-3 hours)
Blood flow velocity measured in the Middle Cerebral Artery via Transcranial Doppler probe secured to the right temporal window.
Measured continuously over the course of each experimental session (i.e. 2-3 hours)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Working Memory
Time Frame: 4 individual measurements taken during each experimental session with each session lasting up to about 3 hours. 1 pre-intervention measurement and 3 post-intervention measurements spaced at least 15min apart
Measured via n-back test (2-back); Subject's will be presented a sequence of letters (25 of them from a base set of 15 letters) one-by-one and will have 3 seconds to indicate whether the letter they see currently matches the letter from 2 frames ago. If there is no match, then they do not need to respond.They will complete three rounds each with a different sequence. Accuracy score (%) = correct inputs/# of stimuli, averaged across 3 blocks.
4 individual measurements taken during each experimental session with each session lasting up to about 3 hours. 1 pre-intervention measurement and 3 post-intervention measurements spaced at least 15min apart
Internal Carotid Artery (ICA) Diameter
Time Frame: 4 individual measurements taken during each experimental session with each session lasting up to about 3 hours. 1 pre-intervention measurement and 3 post-intervention measurements spaced at least 15min apart
Measured via Ultrasound; diameter will be measured as the peak of the pulse wave
4 individual measurements taken during each experimental session with each session lasting up to about 3 hours. 1 pre-intervention measurement and 3 post-intervention measurements spaced at least 15min apart
Internal Carotid Artery (ICA) Pulse Velocity
Time Frame: 4 individual measurements taken during each experimental session with each session lasting up to about 3 hours. 1 pre-intervention measurement and 3 post-intervention measurements spaced at least 15min apart
Measured via Ultrasound; velocity will be assessed at the peak of each pulse wave
4 individual measurements taken during each experimental session with each session lasting up to about 3 hours. 1 pre-intervention measurement and 3 post-intervention measurements spaced at least 15min apart

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Heart Rate
Time Frame: Measured continuously over the course of each experimental session (i.e. 2-3 hours)
Measured via three-lead ECG
Measured continuously over the course of each experimental session (i.e. 2-3 hours)
End Tidal CO2 (ETCO2)
Time Frame: Measured continuously over the course of each experimental session (i.e. 2-3 hours)
Measured via Capnograph; connected nasal cannulas are placed in the nostrils and respiration will be assessed continuously
Measured continuously over the course of each experimental session (i.e. 2-3 hours)
Mean Arterial Pressure (MAP)
Time Frame: Measured continuously over the course of each experimental session (i.e. 2-3 hours)
Measured via Finger photoplethysmography (Non-Invasive Blood Pressure; NIBP), pressure cuffs on the subjects fingers will take continual blood pressure readings via continual inflation and deflation
Measured continuously over the course of each experimental session (i.e. 2-3 hours)
Augmentation Index (AI)
Time Frame: 4 individual measurements taken during each experimental session with each session lasting up to about 3 hours. 1 pre-intervention measurement and 3 post-intervention measurements spaced at least 15min apart
Measured via Pulse Wave Analysis; a SphygmoCor device probe will be held on carotid artery and pulse wave will be analyzed
4 individual measurements taken during each experimental session with each session lasting up to about 3 hours. 1 pre-intervention measurement and 3 post-intervention measurements spaced at least 15min apart
Pulse Wave Velocity (Brachial-Femoral)
Time Frame: 4 individual measurements taken during each experimental session with each session lasting up to about 3 hours. 1 pre-intervention measurement and 3 post-intervention measurements spaced at least 15min apart
Measured via SphygmoCor; distances between brachial artery and femoral artery will be taken for calibration, cuffs at the brachial and femoral arteries will inflate and SphygmoCor will take pulse wave measurements
4 individual measurements taken during each experimental session with each session lasting up to about 3 hours. 1 pre-intervention measurement and 3 post-intervention measurements spaced at least 15min apart
Internal Carotid Artery (ICA) Distensibility
Time Frame: 4 individual measurements taken during each experimental session with each session lasting up to about 3 hours. 1 pre-intervention measurement and 3 post-intervention measurements spaced at least 15min apart
Measured via Ultrasound; diameter will be measured during both systole and diastole
4 individual measurements taken during each experimental session with each session lasting up to about 3 hours. 1 pre-intervention measurement and 3 post-intervention measurements spaced at least 15min apart

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Virginia

Investigators

  • Principal Investigator: Jason Allen, PhD, University of Virginia

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 14, 2022

Primary Completion (Actual)

May 1, 2023

Study Completion (Actual)

May 1, 2023

Study Registration Dates

First Submitted

November 11, 2021

First Submitted That Met QC Criteria

November 11, 2021

First Posted (Actual)

November 23, 2021

Study Record Updates

Last Update Posted (Actual)

November 29, 2023

Last Update Submitted That Met QC Criteria

November 28, 2023

Last Verified

November 1, 2023

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • HSR200454

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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