Monitoring the Effect of Mental Fatigue on Physical Performance Using Wearable Sensors and Physiological Parameters

NCT07323810 | Recruiting

• 1 other identifier: EC-2025-113
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

Mental fatigue (MF) negatively affects both cognitive and physical performance, increasing the risk of errors in high-stakes environments such as sports and surgery. Traditional methods to assess MF rely on subjective self-report scales, which are prone to bias, or on complex brain measurements (e.g. EEG) that are impractical outside laboratory settings. This study aims to develop a real-time, objective monitoring method for MF using wearable physiological sensors. The study will recruit healthy, trained runners (18-35 years old) who will complete both an MF-inducing cognitive task (Stroop test) and a control condition (watching a documentary) in a randomized, counterbalanced, crossover design. Heart rate variability, respiration rate, and pupil metrics will be continuously recorded using wearable devices. Machine learning models will be used to predict MF-level as well as the effect of MF on physical performance (5-km time trial on a treadmill) using the physiological data as input.

Conditions

Mental Fatigue

Keywords

Fatigue; Performance; Physiology; Wearables

Outcome Measures

Primary Outcomes (9)

• Heart rate variability time-domain parameters

  Root mean square of successive differences \[RMSSD\], standard deviation of normal-to-normal intervals \[SDNN\] in milliseconds.

  Continuously during the cognitive intervention and control condition on the study day (approximately 75 minutes).

• Heart rate variability frequency-domain parameters

  Low-frequency (LF), High-frequency (HF) in milliseconds squared (ms²) and Low/high-frequency ratio \[LF/HF\]

  Continuously during the cognitive intervention and control condition on the study day (approximately 75 minutes).

• Respiration rate

  Respiration rate (RR) will be measured as the number of breaths per minute (breaths/min)

  Continuously during the cognitive intervention and control condition on the study day (approximately 75 minutes).

• Pupil diameter

  Pupil diameter (PD) will be measured in millimeters (mm) as an index of autonomic nervous system activity.

  Continuously during the cognitive intervention and control condition on the study day (approximately 75 minutes).

• Blinking rate

  Blinking rate (BR) will be measured as the number of spontaneous blinks per minute (blinks/min)

  Continuously during the cognitive intervention and control condition on the study day (approximately 75 minutes).

• Eyelid opening

  Eyelid opening (EO) will be measured as the vertical distance between the upper and lower eyelid in millimeters (mm).

  Continuously during the cognitive intervention and control condition on the study day (approximately 75 minutes).

• Cognitive Performance Accuracy

  Cognitive performance will be evaluated using a Go/No-Go task. The task begins with a general instruction screen, followed by the simultaneous presentation of two types of stimuli: a Go or No-Go signal and a left or right directional indicator. This results in four possible combinations: GoRight, GoLeft, NoGoRight, and NoGoLeft. When a Go signal appears, participants must respond by pressing the arrow key corresponding to the left or right direction. In contrast, when a No-Go signal is displayed, participants must withhold any response, regardless of the directional cue. This paradigm is designed to assess attention, response inhibition, working memory, and executive functions, all of which are known to be negatively affected by MF. Accuracy in percentage (%) of correct answers on this Go/No-Go task as well as accuracy during the Stroop intervention task will be measured.

  At baseline (pre-intervention), during the 60-minute cognitive intervention, and immediately after completion of the intervention on the study day (approximately 70 minutes total).

• Cognitive Performance Reaction Time

  Cognitive performance will be evaluated using a Go/No-Go task. The task begins with a general instruction screen, followed by the simultaneous presentation of two types of stimuli: a Go or No-Go signal and a left or right directional indicator. This results in four possible combinations: GoRight, GoLeft, NoGoRight, and NoGoLeft. When a Go signal appears, participants must respond by pressing the arrow key corresponding to the left or right direction. In contrast, when a No-Go signal is displayed, participants must withhold any response, regardless of the directional cue. This paradigm is designed to assess attention, response inhibition, working memory, and executive functions, all of which are known to be negatively affected by MF. Reaction time (RT) will be measured in milliseconds (ms) as the latency between stimulus onset and the participant's behavioral response (button press) on the Go/No-Go task and during the Stroop intervention task.

  At baseline (pre-intervention), during the 60-minute cognitive intervention, and immediately after completion of the intervention on the study day (approximately 70 minutes total).

• Physical performance: Time to Completion

  Participants will perform a 5-km running time trial on a treadmill to assess endurance performance under MF. The treadmill will be set at a 1% gradient, following established protocols to replicate outdoor running conditions. Before beginning the time trial, participants will complete a standardized warm-up for 5 minutes. To maintain self-paced running conditions, participants will receive real-time feedback on the distance covered but will not be provided with information about running speed or elapsed time. Researchers will remain present but will not offer verbal encouragement or pacing cues to ensure that the effort remains internally regulated. Once the 5-km distance is completed, participants will immediately stop running and step onto the treadmill's side platforms. The total time elapsed will be recorded.

  Immediately after completion of the 60-minute cognitive intervention, during a single 5-km treadmill time trial on the study day (approximately 20 minutes).

Secondary Outcomes (7)

• Subjective feeling of Mental Fatigue

  At baseline (pre-intervention), every 5 minutes during the 60-minute cognitive intervention, and immediately after completion of the intervention on the study day.

• Mood

  At baseline, prior to the start of each experimental and control trial on the study day.

• Motivation

  At baseline (pre-intervention) and immediately after completion of the 60-minute cognitive intervention on the study day.

• Sleepiness

  At baseline (pre-intervention) and immediately after completion of the 60-minute cognitive intervention on the study day.

• Physical fatigue

  Immediately prior to the physical performance test on the study day.

Study Arms (2)

Mental Fatigue Condition

EXPERIMENTAL

The mental fatigue task will involve a modified Stroop test, adapted from previous research. Words will appear on the screen in 34-point font for 1000 milliseconds, with the inter-stimulus interval personalized based on each participant's Stroop max test performance. Stroop task duration will be 60 minutes for every participant. Participants will be instructed to respond as quickly and accurately as possible.

Behavioral: Mental Fatigue

Control condition

NO INTERVENTION

The control task will consist of watching a pre-approved, emotionally neutral 60-minute documentary.

Interventions

Mental Fatigue BEHAVIORAL

Mental fatigue (MF) is a psychobiological state characterized by feelings of tiredness and/or a measurable decline in performance following prolonged or intense cognitive activity.

Mental Fatigue Condition

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy (no neurological, cardiovascular or musculoskeletal disorders of any kind)
• Male or female
• No prior knowledge of the concept of MF
• No medication
• Non-smoker
• years of age
• Experienced runners: (≥15km/week and/or ≥2u/week during the last 6 months)

You may not qualify if:

• Injuries in the past 6 months, affecting running performance
• Suffering from a chronic health condition (could be neurological, cardiovascular, internal or musculoskeletal)
• Participating in any concomitant care or research trials
• History of suffering from any mental/psychiatric disorders
• Use of medication
• Use of caffeine and heavy efforts 24 hours prior each trial
• Suffering from colour vision deficiencies
• Not eating a standardized meal, the morning of each trial and the evening before each trial

Sponsors & Collaborators

• Vrije Universiteit Brussel: lead

Study Sites (1)

Brussels Labo voor Inspanning en Topsport

Brussels, 1050, Belgium

RECRUITING

MeSH Terms

Conditions

Mental Fatigue; Fatigue

Condition Hierarchy (Ancestors)

Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Behavioral Symptoms; Behavior

Central Study Contacts

Emilie Schampheleer, Msc

CONTACT

26292222; emilie.schampheleer@vub.be

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor Doctor

Study Record Dates

• First Submitted: August 22, 2025
• First Posted: January 7, 2026
• Study Start: January 1, 2026
• Primary Completion (Estimated): June 1, 2026
• Study Completion (Estimated): June 1, 2026
• Last Updated: January 7, 2026

Record last verified: 2025-08

Data Sharing

• IPD Sharing: Will not share

Locations

BE (1)