Optimizing Combined Physical and Cognitive Activity in Community-Dwelling Older Adults. (CONSCIOUS)

Determining the Optimal Combination of Physical and Cognitive Activity for Acute Cognitive Benefits in Community-Dwelling Older Adults.

This laboratory-based interventional study aims to determine which combination of physical activity intensity and cognitive activity difficulty yields the greatest acute cognitive benefits in community-dwelling older adults.

The main question it aims to answer is:

- Which combination of physical and cognitive activity results in the greatest short-term improvement in cognitive functioning?

Researchers will compare four different combinations of physical intensity and cognitive task difficulty to determine whether one combination stands out. In addition, the study examines whether these effects differ depending on baseline cardiorespiratory fitness.

Participants will:

• undergo a preparatory phase in which their cardiorespiratory fitness, individualized physical activity intensity levels, and cognitive activity difficulty levels are established
• visit the laboratory four times, with one week between visits, to complete each combination of physical and cognitive activity (light vs. moderate physical activity × easy vs. challenging cognitive activity)
• complete cognitive tests immediately before and after each condition

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Behavioral: Light physical activity + easy cognitive activity; Behavioral: Light physical activity + challenging cognitive activity; Behavioral: Moderate physical activity + easy cognitive activity; Behavioral: Moderate physical activity + challenging cognitive activity

Detailed Description

Recognizing the escalating dementia rates, its profound social and economic consequences and the lack of curative treatments, the World Health Organization (WHO) emphasizes the importance of reducing modifiable risk factors for dementia, as outlined in Action Area 3 of the WHO Global action plan on the public health response to dementia 2017-2025. Previous research suggests that combining physical activity and cognitive activity may produce greater cognitive benefits than either activity alone, but it remains unclear which specific combinations are most effective in older adults. In particular, little is known about how physical activity intensity and cognitive activity difficulty interact, and whether cardiorespiratory fitness influences these effects. The present study addresses this knowledge gap in community-dwelling older adults.

The study is conducted in two consecutive parts. In the preparatory phase, participants attend one laboratory visit. During this phase, baseline screening and descriptive assessments will be performed, cardiorespiratory fitness will beestimated using the 6-Minute Walk Test, individualized physical activity intensity zones will be determined using heart-rate reserve, and cognitive activities will be classified as easy or challenging based on subjective ratings. Participants will also be familiarized with treadmill walking and simultaneous physical and cognitive task performance.

In the fundamental phase, eligible participants will complete four laboratory sessions in randomized order, each involving one combination of physical and cognitive activity: light physical activity with easy cognitive activity, light physical activity with challenging cognitive activity, moderate physical activity with easy cognitive activity, and moderate physical activity with challenging cognitive activity. During each session, participants walk on a treadmill at a prescribed heart-rate-based intensity while simultaneously performing cognitive tasks. Cognitive functioning is assessed immediately before and after each session using three tasks from the CANTAB neuropsychological test battery: a) Multitasking test (MTT), (b) Delayed Matching to Sample (DMS), and (c) Match to Sample Visual Search (MTS), allowing the study to examine the short-term cognitive effects of each physical activity × cognitive activity combination. The overall aim is to identify the optimal combination of simultaneous physical and cognitive activity for acute cognitive benefits in older adults.

• Study Type: Interventional
• Enrollment (Actual): 53
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Belgium
  • Ghent, Belgium, 9000
    • University Ghent

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Aged 65 years or older
• Community-dwelling
• Able to safely walk on a treadmill and complete the 6-Minute Walk Test
• Sufficient Dutch proficiency to understand study instructions and complete study procedures

Exclusion Criteria:

• MoCA score < 23
• Severe cognitive or physical impairment that would hinder participation or understanding of study procedures
• Use of medication affecting heart rate
• Any medical condition contraindicating engagement in physical or cognitive activity
• Severe visual or hearing impairment that would prevent valid participation in the study procedures

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Sequence 1; Participants complete the four experimental conditions in the following order across four separate laboratory visits: C1, C2, C3, and C4. C1 = light physical activity + easy cognitive activity; C2 = light physical activity + challenging cognitive activity; C3 = moderate physical activity + easy cognitive activity; C4 = moderate physical activity + challenging cognitive activity.	Behavioral: Light physical activity + easy cognitive activity; Participants walk on a treadmill at an individualized light physical activity intensity (30-39% of heart rate reserve) while performing cognitive tasks individually classified as easy.; Behavioral: Light physical activity + challenging cognitive activity; Participants walk on a treadmill at an individualized light physical activity intensity (30-39% of heart rate reserve) while performing cognitive tasks individually classified as challenging.; Behavioral: Moderate physical activity + easy cognitive activity; Participants walk on a treadmill at an individualized moderate physical activity intensity (40-59% of heart rate reserve) while performing cognitive tasks individually classified as easy.; Behavioral: Moderate physical activity + challenging cognitive activity; Participants walk on a treadmill at an individualized moderate physical activity intensity (40-59% of heart rate reserve) while performing cognitive tasks individually classified as challenging.
Experimental: Sequence 2; Participants complete the four experimental conditions in the following order across four separate laboratory visits: C2, C4, C1, and C3. C1 = light physical activity + easy cognitive activity; C2 = light physical activity + challenging cognitive activity; C3 = moderate physical activity + easy cognitive activity; C4 = moderate physical activity + challenging cognitive activity.	Behavioral: Light physical activity + easy cognitive activity; Participants walk on a treadmill at an individualized light physical activity intensity (30-39% of heart rate reserve) while performing cognitive tasks individually classified as easy.; Behavioral: Light physical activity + challenging cognitive activity; Participants walk on a treadmill at an individualized light physical activity intensity (30-39% of heart rate reserve) while performing cognitive tasks individually classified as challenging.; Behavioral: Moderate physical activity + easy cognitive activity; Participants walk on a treadmill at an individualized moderate physical activity intensity (40-59% of heart rate reserve) while performing cognitive tasks individually classified as easy.; Behavioral: Moderate physical activity + challenging cognitive activity; Participants walk on a treadmill at an individualized moderate physical activity intensity (40-59% of heart rate reserve) while performing cognitive tasks individually classified as challenging.
Experimental: Sequence 3; Participants complete the four experimental conditions in the following order across four separate laboratory visits: C3, C1, C4, and C2. C1 = light physical activity + easy cognitive activity; C2 = light physical activity + challenging cognitive activity; C3 = moderate physical activity + easy cognitive activity; C4 = moderate physical activity + challenging cognitive activity.	Behavioral: Light physical activity + easy cognitive activity; Participants walk on a treadmill at an individualized light physical activity intensity (30-39% of heart rate reserve) while performing cognitive tasks individually classified as easy.; Behavioral: Light physical activity + challenging cognitive activity; Participants walk on a treadmill at an individualized light physical activity intensity (30-39% of heart rate reserve) while performing cognitive tasks individually classified as challenging.; Behavioral: Moderate physical activity + easy cognitive activity; Participants walk on a treadmill at an individualized moderate physical activity intensity (40-59% of heart rate reserve) while performing cognitive tasks individually classified as easy.; Behavioral: Moderate physical activity + challenging cognitive activity; Participants walk on a treadmill at an individualized moderate physical activity intensity (40-59% of heart rate reserve) while performing cognitive tasks individually classified as challenging.
Experimental: Sequence 4; Participants complete the four experimental conditions in the following order across four separate laboratory visits: C4, C3, C2, and C1. C1 = light physical activity + easy cognitive activity; C2 = light physical activity + challenging cognitive activity; C3 = moderate physical activity + easy cognitive activity; C4 = moderate physical activity + challenging cognitive activity.	Behavioral: Light physical activity + easy cognitive activity; Participants walk on a treadmill at an individualized light physical activity intensity (30-39% of heart rate reserve) while performing cognitive tasks individually classified as easy.; Behavioral: Light physical activity + challenging cognitive activity; Participants walk on a treadmill at an individualized light physical activity intensity (30-39% of heart rate reserve) while performing cognitive tasks individually classified as challenging.; Behavioral: Moderate physical activity + easy cognitive activity; Participants walk on a treadmill at an individualized moderate physical activity intensity (40-59% of heart rate reserve) while performing cognitive tasks individually classified as easy.; Behavioral: Moderate physical activity + challenging cognitive activity; Participants walk on a treadmill at an individualized moderate physical activity intensity (40-59% of heart rate reserve) while performing cognitive tasks individually classified as challenging.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Multitasking Test (MTT) performance from pre- to post-condition	Change in accuracy and response latency from pre- to post-condition on the Multitasking Test (MTT), assessing executive functioning, cognitive flexibility, and processing speed.	Immediately before and 10 minutes after each experimental condition
Change in Delayed Matching to Sample (DMS) performance from pre- to post-condition	Change in accuracy and response latency from pre- to post-condition on the Delayed Matching to Sample (DMS), assessing short-term visual recognition memory.	Immediately before and 10 minutes after each experimental condition
Change in Match to Sample Visual Search (MTS) performance from pre- to post-condition	Change in accuracy and response latency from pre- to post-condition on the Match to Sample Visual Search (MTS), assessing visual attention and psychomotor speed.	Immediately before and 10 minutes after each experimental condition

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
General impression of each experimental condition	Self-reported general impression of each experimental condition, rated on a 0-10 scale, where 0 indicates "not good at all" and 10 indicates "very good."	Immediately after each experimental condition, during the 10-minute post-condition interval.
Perceived feasibility of each experimental condition	Self-reported feasibility of each experimental condition, rated on a 0-10 scale in response to the statement "I feel capable of doing this session," where higher scores indicate greater perceived feasibility.	Immediately after each experimental condition, during the 10-minute post-condition interval.
Enjoyment of each experimental condition	Self-reported enjoyment of each experimental condition, rated on a 0-10 scale in response to the statement "I enjoyed this session," where higher scores indicate greater enjoyment.	Immediately after each experimental condition, during the 10-minute post-condition interval.

Collaborators and Investigators

• Sponsor: University Ghent
• Investigators: Principal Investigator: Greet Cardon, Prof. Dr., University Ghent

Study record dates

Study Major Dates

• Study Start (Actual): February 2, 2026
• Primary Completion (Actual): May 13, 2026
• Study Completion (Actual): May 13, 2026

Study Registration Dates

• First Submitted: June 1, 2026
• First Submitted That Met QC Criteria: June 1, 2026
• First Posted (Actual): June 5, 2026

Study Record Updates

• Last Update Posted (Actual): June 5, 2026
• Last Update Submitted That Met QC Criteria: June 1, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: physical activity; community-dwelling older adults; healthy ageing; cognitive activity
• Additional Relevant MeSH Terms: Behavior; Motor Activity
• Other Study ID Numbers: CONSCIOUS - ONZ-2025-0282

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data collected during the study will be made available to other researchers. The exact dataset(s), supporting documents, timing, and access procedures will be specified after completion of the main analyses and publication of the primary study results.
• IPD Sharing Time Frame: De-identified individual participant data will become available after publication of the primary study results and are expected to remain available indefinitely in an institutional or open research repository.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF

Drug and device information, study documents

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