The Role of the Brain in Mental and Physical Fatigue

Investigating Fundamental Mechanisms of Mental and Physical Fatigue Using Neurotransmitter Reuptake Inhibitors and Electroencephalography: a Randomized Counterbalanced Crossover Trial

The goal of this clinical trial is to determine the role of brain neurotransmission in the onset of fatigue, identify the brain areas involved, and determine how brain activity and neuromuscular efficiency changes during onset of fatigue. Three different experimental studies (physical fatigue, mental fatigue and combined) will be performed with a randomized, single-blinded, placebo controlled, counter-balanced, cross-over design.

The objectives of the projects are as follows:

• To experimentally assess the role of a dopamine, and a noradrenalin reuptake inhibitor in the onset of exercise-induced fatigue
• To identify changes in brain activation associated with altered PF and fatigue perception
• To experimentally assess the effect of a NA or DA reuptake inhibitor on MF, brain activation and the sources of changes in brain activation
• To experimentally assess the role of brain neurotransmitters (DA, NA) in the interaction between mental and PF from a neurophysiological perspective.

Participants will be healthy young adults. In each study, they will start with a familiarization trial followed by two experimental trials and one control trial with a randomized treatment order. At each visit, different drugs will be administered to elicit different neurotransmitter response. The trials will be performed at the MFYS exercise lab (BLITS, VUB campus Etterbeek, Boulevard General Jaques 271, 1050 Elsene (Brussels)).

Depending on the type of study they are participating in, participants will perform three distinct tasks:

• In the first experimental study participants will perform a 60-min Stroop Task to elicit mental fatigue.
• In the second experimental study participants will perform a knee-extension exercise until exhaustion to elicit physical fatigue.
• In third experimental study participants will first preform a mental fatiguing task (Stroop taks) followed by physical fatigue task (knee extension).

While participants will perform above mentioned task their EEG signal and heart rate will be measured. At the same time, participants will report on their subjective feeling of fatigue during these tasks. In addition, all participants will be administered cognitive tasks before and after the study, along with questionnaires. In the second and third experiments, tensiomyography and electromyography will also be recorded from the quadriceps muscle of the leg used for knee extension.

Researchers will compare physiological and behavioural changes in response to specific neurotransmitter drug to answer the main question: what the role of a DA and a NA reuptake inhibitor on the onset of mental and physical fatigue is.

Study Overview

• Status: Recruiting
• Conditions: Fatigue
• Intervention / Treatment: Drug: Reboxetine Pill; Drug: Methylphenidate Oral Product

• Study Type: Interventional
• Enrollment (Estimated): 62
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Yahaira Laurisa Arenales Arauz, Msc; Phone Number: +31615076269; Email: laurisa.arenales@vub.be
• Study Contact Backup: Name: Tjaša Ocvirk, Msc; Phone Number: +38631278074; Email: tjasa.ocvirk@vub.be

Study Locations

• Belgium
  • Brussels, Belgium, 1050
    • Recruiting
    • Brussels Labo voor Inspanning & Topsport U-residence
    • Contact: Phone Number: +32 (0)2 629 22 22

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy trained individuals (exercises at least 1x per week, no neurological, cardiovascular internal or musculoskeletal disorders of any kind)
• No use of chronic or occasional prescribed medication (except for contraceptives)
• Non-smoker

Exclusion Criteria:

• Injuries of any kind in the past 6 months
• Pregnancy
• Specific food or drink allergies (e.g. lactose and/or gluten intolerance)
• Suffering from a chronic health condition (could be neurological, cardiovascular, internal and musculoskeletal)
• Participating in any concomitant care or research trials
• History of suffering from any mental/psychiatric disorders:

Suffering from a higher risk of burn out, indicated by a total score of more than 2.59 on the Burn out assessment tool (BAT) Suffering from high general fatigue, indicated by a score of more than 57 on the Multidimensional fatigue inventory (MFI) Suffering from depression, indicated by a score of more than16 on the Beck depression inventory-II (BDI-II)

• Use of medication Chronic use with an exception for contraceptives Prescribed medication in between or before trials Use of non-prescribed occasional medication 24 hours prior each trial
• 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

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Mental fatigue group	Drug: Reboxetine Pill; 8 mg; Drug: Methylphenidate Oral Product; 20 mg
Other: Physical fatigue group	Drug: Reboxetine Pill; 8 mg; Drug: Methylphenidate Oral Product; 20 mg
Other: Combined group	Drug: Reboxetine Pill; 8 mg; Drug: Methylphenidate Oral Product; 20 mg

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of repetitions	Number of repetitions during knee extension task	30 minutes
Electroencephalography (spectral analysis)	measurement of cortical activity with 64 channels (spectral density in alpha, beta, gamma, delta, theta)	80 minutes
Electroencephalography (event related potentials)	measurement of cortical activity with 64 channels (event related potentials)	80 minutes
Electromyography	Target muscles are rectus femoris and vastus lateralis (median frequency)	60 minutes
Accuracy	Accuracy of correct answers during Stroop task	60 minutes
Reaction time	Reaction time for answers during Stroop task	60 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Perceived stress scale questionnaire (PSS-10)	Result is the score of the questionnaire (may 40 points)	5 minites
the international physical activity questionnaire short form (IPAQ-SF)	Result is the score of the questionnaire	2 minutes
The Brunel Mood Scale (BRUMS)	Result is the score of the questionnaire (each subscale max 0-16)	5 minutes
Motivation with visual analog score (Moti-VAS)	Result is the score between 0 and 100	1 minute
The National Aeronautics and Space Administration Task Load Index (NASA-TLX)	Result is the score of the questionnaire	3 minutes
Subjective feeling of Mental Fatigue with visual analog score (M-VAS)	Result is the score between 0 and 100	1 minute
Subjective feeling of physical fatigue with visual analog score (P-VAS)	Result is the score between 0 and 100	1 minute
Karolinska Sleepiness Scale (KSS)	Result is the score of the questionnaire (max 24)	5 minutes
Internal load of the physical performance (CR100 RPE)	Result is the score between 0 and 100	30 minutes
Heart Rate	continuously assessed by using the POLAR H10 sensor	60 minutes
Lactate concentration	blood lactate will be measured at the beginning and end of the trial at the finger tip of the participant (unit = mmol/L)	5 minutes

Collaborators and Investigators

• Sponsor: Vrije Universiteit Brussel
• Collaborators: Science and Research Centre Koper

Study record dates

Study Major Dates

• Study Start (Actual): May 3, 2023
• Primary Completion (Estimated): December 31, 2025
• Study Completion (Estimated): December 31, 2025

Study Registration Dates

• First Submitted: May 9, 2023
• First Submitted That Met QC Criteria: May 19, 2023
• First Posted (Actual): May 30, 2023

Study Record Updates

• Last Update Posted (Actual): June 18, 2025
• Last Update Submitted That Met QC Criteria: June 15, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Fatigue; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Neurotransmitter Agents; Membrane Transport Modulators; Psychotropic Drugs; Adrenergic Agents; Central Nervous System Stimulants; Dopamine Uptake Inhibitors; Neurotransmitter Uptake Inhibitors; Dopamine Agents; Antidepressive Agents; Adrenergic Uptake Inhibitors; Reboxetine; Methylphenidate
• Other Study ID Numbers: G095422N

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
• product manufactured in and exported from the U.S.: No