Combined Exercise Trial (COMET)

Differential Effects of Exercise Modality on Cognition and Brain in Older Adults

The number of older Americans will double in the next 4 decades to nearly 90 million, placing an unprecedented financial and resource burden on the health care system. Exercise has clear and demonstrable physical benefits, but a more precise understanding of how exercise supports cognitive function is essential. Demonstrating definitively that exercise as recommended by public health entities has benefits for cognition would have enormous public health implications, encourage the public to adapt more active lifestyles, and stimulate the development of effective exercise delivery programs.

Study Overview

• Status: Completed
• Conditions: Healthy Aging
• Intervention / Treatment: Behavioral: Exercise

Detailed Description

Older adults often experience physical decline that can be directly ameliorated by physical activity and exercise. Evidence is building that exercise prevents cognitive decline or delays the onset of debilitating dementia (e.g. Alzheimer's disease) yet, the optimal dose and combination of exercise modalities for promoting brain health, however, remains unknown and essentially untested.

The long-term research goal of this project is to develop and test strategies to support successful aging and prevent Alzheimer's disease. The study will enroll 280 individuals, age 65 to 80 years without cognitive impairment, into a 26-week exercise intervention to test the combined and independent effects of aerobic and resistance training on cognition, brain structure, and physical function. The project will also explore underlying biological mechanisms that may link exercise with brain health.

Participants will be randomized into 1 of 4 groups: flexibility, toning and balance (control), aerobic exercise training, progressive resistance training, or combined aerobic and resistance training. All intervention groups represent the most common modalities of exercise and directly reflect the public health recommendations for aerobic and resistance training. Exercise training will occur in a community setting through the network of Greater Kansas City Young Men's Christian Association. It is hypothesized that 26 weeks of exercise will improve 1) cognitive performance, 2) regional brain volume, 3) cardiorespiratory fitness and strength 4) biomarkers.

This will be the largest study to assess the combined and independent effects of the two most recommended forms of exercise. Demonstrating specific exercise effects on cognitive function and brain health in older adults would have enormous public health implications. The study's results will also impact public health policy and education by providing evidence towards the specific or synergistic effects of aerobic and resistance training on cognition and brain structure. Encouraging the public to adapt more active lifestyles and stimulate the development of effective exercise delivery programs to enhance initiation and maintenance of physical activity interventions is key to increasing the number of quality years of life for America's aging population.

• Study Type: Interventional
• Enrollment (Actual): 282
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Kansas
    • Fairway, Kansas, United States, 66205
      • University of Kansas Alzheimer's Disease Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 65 years to 80 years (Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age 65-80 yrs (inclusive at time of consent).
• Conversant English speaking and reading ability.
• Medical clearance by a health care provider.
• Reliable means of transportation.
• Telephone Interview of Cognitive Status score > 25 and adjudication of normal cognition based on cognitive test data by a study medical monitor.

Exclusion Criteria:

• Intention to move out of the area or travel for more than 4 weeks in the next year.
• Use of an assistive device for ambulation.
• Joint pain severe enough to prevent taking walks in community, lifting objects over your head due to pain or restriction of movement, or that is worsened by increasing physical activity.
• Any MRI contraindications or refusal to attempt MRI.
• Treatment for alcohol or substance abuse in the last 2 years.
• Treatment for cancer (other than non-metastatic, localized cancer) in the last 2 years.
• Currently taking insulin.
• Diagnosis of heart disease, heart failure, heart attack, or heart surgery or chest pain with effort in the last 2 years.
• Untreated atrial fibrillation, valve replacements, angioplasty or stent placement in the last 2 years regardless of physician clearance.
• History of major psychiatric illness including schizophrenia (not including general anxiety disorder or depression), multiple sclerosis, Parkinson's, Dementia, mild cognitive impairment, brain injury (traumatic or clinically evident Stroke), or similar, likely to negatively impact cognitive testing.
• Head injury with loss of consciousness for more than a few minutes.
• Change in blood pressure medication in the last 2 months.
• Considered "Active" or engaging in a progressive resistance training 2 or more times a week.
• reported condition likely to compromise ability to safely perform exercise as determined by study medical monitor (e.g. chronic obstructive pulmonary disease, Lupus, end stage renal disease, etc.)

Study Plan

How is the study designed?

Design Details

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

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Core and Fusion Training; 150 minutes/week of Core and Fusion exercise, a mix of low impact toning, strengthening, flexibility and balance exercises.	Behavioral: Exercise; Standard public health exercise recommendations; Other Names: Weight Training, Aerobic Exercise, Progressive Resistance Exercise, Cross Training
Active Comparator: Endurance Training; Moderate-intensity endurance training such as brisk walking, 150 minutes/week over 3-5 days. Progression based on a set schedule. In addition 0-2 days of Core and Fusion control exercise will also be recommended.	Behavioral: Exercise; Standard public health exercise recommendations; Other Names: Weight Training, Aerobic Exercise, Progressive Resistance Exercise, Cross Training
Active Comparator: Weight Training; Progressive resistance training 2 days/week, non-consecutive, of 2 sets (10 - 15 repetitions) of 10 exercises (~75 minutes/week). Progression based on repetition completion and 1-repetition maximum. In addition 3 days of Core and Fusion control exercise will also be recommended.	Behavioral: Exercise; Standard public health exercise recommendations; Other Names: Weight Training, Aerobic Exercise, Progressive Resistance Exercise, Cross Training
Active Comparator: Combined Endurance and Weight Training; Moderate-intensity endurance training such as brisk walking, 150 minutes/week over 3-5 days. Progression based on a set schedule. Progressive resistance training 2 days/week, non-consecutive, of 2 sets (10 - 15 repetitions) of 10 exercises (~75 minutes/week). Progression based on repetition completion and 1-repetition maximum.	Behavioral: Exercise; Standard public health exercise recommendations; Other Names: Weight Training, Aerobic Exercise, Progressive Resistance Exercise, Cross Training

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Global Cognition	Assessing change in cognitive function from baseline to 12 months. The 6 month measure is being used to assess the trajectory of the change. A comprehensive neuropsychological battery will be used that assesses a global cognition score derived from domains of cognition (e.g. Executive Function, Visuospatial Processing, Episodic Memory, Processing Speed). We will use a second order confirmatory factor analysis (CFA) to estimate the factor loadings between the observed indicators and the first order factors and between the first and second order factors. The CFA will use baseline data to avoid any potential intervention related biases. The primary outcome will be constructed by summing the weighted average (by the estimated first and second order loadings) of the standardized observed scores across the cognitive tests.	Baseline, 6 months, 12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hippocampal volume	Volume of bilateral hippocampus in milliliters	Baseline, 12 months
Peak oxygen consumption	Peak volume of oxygen used in in milliliters per kilogram of body mass per minute during a graded maximal exercise test	Baseline, 12 months
1-Repetition Maximum	The maximum amount of mass that can be lifted one time (summed leg press and chest press)	Baseline, 12 months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hopkins Verbal Learning Test - Revised	The Hopkins Verbal Learning Test - Revised is an oral test that has been validated within brain-disordered populations (e.g., Alzheimer's disease, amnestic disorders) as a measure of verbal learning and memory.	Baseline, 6 months, 12 months
NIH Toolbox Flanker Task	The NIH ToolboxFlanker Task is a computer based test to assess selective attention and inhibitory function.	Baseline, 6 months, 12 months
NIH Toolbox Dimensional Change Card Sort	The NIH Toolbox Dimensional Change Card Sort is a computer based test to assess cognitive flexibility and attention.	Baseline, 6 months, 12 months
NIH Toolbox Oral Symbol Digit Test	The NIH Toolbox Oral Symbol Digit Test is a computer based test to Measure of processing speed.	Baseline, 6 months, 12 months
Virginia Cognitive Aging Project Logical Memory	The Virginia Cognitive Aging Project Logical Memory test measures episodic verbal memory.	Baseline, 6 months, 12 months
Letter Comparison	This paper-based task measures processing speed.	Baseline, 6 months, 12 months
Matrix Reasoning	This computer-based task measures visuospatial ability.	Baseline, 6 months, 12 months
Task Switching	This computer task asks participants to learn two different tasks. This task measures task switching.	Baseline, 6 months, 12 months
Spatial Working Memory	This computer task measures spatial memory.	Baseline, 6 months, 12 months
Stroop Task	This paper-based oral task measures executive control, specifically attention and inhibitory control.	Baseline, 6 months, 12 months
Fat Mass	Estimated total body, axial, appendicular and visceral fat mass from dual x-ray absorptiometry.	Baseline, 12 months
Lean Mass	Estimated total body, axial, appendicular lean mass from dual x-ray absorptiometry.	Baseline, 12 months
Bone Mass	Estimated total body, axial, appendicular bone mass and density from dual x-ray absorptiometry.	Baseline, 12 months
Cerebral brain blood flow	Whole brain and regional cerebral blood flow estimated using arterial spin labeling, a technique of magnetic resonance imaging	Baseline, 12 months
Senior Fitness Test	Composite and sub-test scores of 6 common physical activities. Scores can be normalized for age and sex	Baseline, 12 months
Waist to Hip Ratio	The circumference of the waist and hip areas are measured via measuring tape.	Baseline, 12 months
Body Mass Index	Height and body mass are measured and Body Mass Index is calculated based on a standard equation.	Baseline, 12 months
Blood lactate concentration	Blood lactate concentration is measured before and after a bout of exercise.	Baseline, 12 months
Pittsburgh Sleep Quality Index	Paper-based questionnaire of self-rated sleep quality.	Baseline, 6 months, 12 months
Perceived Stress Scale, 10-item	Paper-based questionnaire of self-rated appraisal of stress.	Baseline, 6 months, 12 months
National Health and Nutrition Examination Survey Diet Survey Questionnaire	Self-rated computer based questionnaire of dietary intake.	Baseline, 6 months, 12 months
Mediterranean Eating Pattern for Americans	Self-rated computer based questionnaire of mediterranean diet eating pattern.	Baseline, 6 months, 12 months
Barriers Self-Efficacy Scale	Self-rated computer based questionnaire of physical activity self-efficacy.	Baseline, 3 months, 6 months, 12 months
Exercise Self-Efficacy Scale	Self-rated computer based questionnaire of exercise goal self-efficacy.	Baseline, 3 months, 6 months, 12 months
Leisure Self-Efficacy Scale	Self-rated computer based questionnaire of leisure-time physical activity self-efficacy.	Baseline, 3 months, 6 months, 12 months
Godin Leisure-Time Exercise Questionnaire	Self-rated computer based measure of use of leisure-time for physical activity	Baseline, 3 months, 6 months, 12 months
Wechsler Test of Adult Reading	The Wechsler Test of Adult Reading is a reading recognition test that can be used to estimate intelligence quotient and memory scores	Baseline
Spatial Relations	In this computer task, participants are asked to determine which three-dimensional figure can be formed from a two-dimensional pattern presented. This task measures visual construction ability.	Baseline, 26-weeks, 52-weeks
MacArthur Scale of Subjective Social Status	The MacArthur Scale of Subjective Social Status (MacArthur Socio-Economic Status Scale) contains questions regarding finances, assets and other home socioeconomics.	Baseline, 6 months, 12 months
Patient-Reported Outcomes Measurement Information System (PROMIS) Applied Cognitive Abilities v1.0	Computer-based adaptive questionnaire of self-rated cognitive function.	Baseline, 6 months, 12 months
Patient-Reported Outcomes Measurement Information System (PROMIS) Applied Cognitive General Concerns v1.0	Computer-based adaptive questionnaire of self-rated cognitive concerns.	Baseline, 6 months, 12 months
Patient-Reported Outcomes Measurement Information System (PROMIS) Anxiety v1.0	Computer-based adaptive questionnaire of self-rated anxiety.	Baseline, 6 months, 12 months
Patient-Reported Outcomes Measurement Information System (PROMIS) Depression v1.0	Computer-based adaptive questionnaire of self-rated depression.	Baseline, 6 months, 12 months
Patient-Reported Outcomes Measurement Information System (PROMIS) Ability to Participate in Social Roles and Activities v1.0	Computer-based adaptive questionnaire of self-rated social roles.	Baseline, 6 months, 12 months
Patient-Reported Outcomes Measurement Information System (PROMIS) General Life Satisfaction v1.0	Computer-based adaptive questionnaire of self-rated life satisfaction.	Baseline, 6 months, 12 months
Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function v1.0	Computer-based adaptive questionnaire of self-rated life physical function.	Baseline, 6 months, 12 months
EuroQol Group Five Dimension Five Level (EQ-5D-5L)	A visual analog scale of quality of life	Baseline, 6 months, 12 months
Physical Activity Self-Regulation Scale, 12-item	Self-rated computer based measure of physical activity self-regulation for use with older adults.	Baseline, 3 months, 6 months, 12 months
Blood biomarkers	Brain Derived Neurotrophic factor , Insulin Growth Factor-1 (IGF-1), lactate, glucose and insulin levels, inflammatory cytokines, plasma phosphorylated tau (various form), plasma beta-amyloid (various forms), neurofilament light, glial fibrillary acidic protein and others as become available.	Baseline, 6 months, 12 months

Collaborators and Investigators

• Sponsor: University of Kansas Medical Center
• Investigators: Principal Investigator: Eric D Vidoni, PhD, University of Kansas Medical Center

Publications and helpful links

General Publications

• Clutton J, Montgomery RN, Mudaranthakam DP, Blocker EM, Shaw AR, Szabo Reed AN, Vidoni ED. An open-source system for efficient clinical trial support: The COMET study experience. PLoS One. 2023 Nov 27;18(11):e0293874. doi: 10.1371/journal.pone.0293874. eCollection 2023.

Study record dates

Study Major Dates

• Study Start (Actual): October 14, 2021
• Primary Completion (Actual): May 22, 2026
• Study Completion (Actual): May 22, 2026

Study Registration Dates

• First Submitted: April 12, 2021
• First Submitted That Met QC Criteria: April 12, 2021
• First Posted (Actual): April 19, 2021

Study Record Updates

• Last Update Posted (Actual): June 3, 2026
• Last Update Submitted That Met QC Criteria: June 1, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Motor Activity; Movement; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Exercise
• Other Study ID Numbers: 146904

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: All data generated during the project will be entered into a secure database. This database will be housed on a secure network drive that is routinely backed-up to an offsite data storage location. Upon completion of the project, all data will be de-identified and available for other investigators at their request, in compliance with the NIH guidelines. It is not anticipated that unique resources will be developed and thus a plan for resource sharing is not provided.

Drug and device information, study documents

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