The Individual Response of Healthy Individuals to Mental Fatigue

The Individual Response of Healthy Individuals to Mental Fatigue: a Randomized Crossover Trial Investigating the Influence of Internal Factors in the Effects of Mental Fatigue on Human Performance

The objective of the present study is to confirm and map out the presence of interindividual differences in the effect of mental fatigue on both physical and cognitive performance, and to see if these differences are related to individual factors of the participants.

Every participant will visit the lab a total of three times within a period of two weeks. In the first visit, they will undergo both a detailed screening as well as perform all intervention/control trial measures to familiarize themselves with the utilised equipment. This detailed screening entails, among other things, a maximal incremental exercise test, a cognitive test battery and multiple subjective questionnaires.

The experimental and control trial are almost identical, with the only difference being the task performed in the middel of the trial. At the beginning of the trial the EEG will be fitted to the head of the participant and baseline measures will be taken. Afterwards, participants will perform a go nogo task to assess baseline cognitive performance. Then the intervention (i.e. Stroop task) or control (i.e. documentary) task will be performed. The goal of the Stroop task is to elicit mental fatigue, while the documentary provides a meaningful comparison. Afterwards, cognitive performance will again be assessed using the go no go task, followed by a physical performance task in the form of a time trial.

The different internal factors assessed during the screening stage will be correlated to the difference in cognitive and physical performance between the intervention and control trial.

Inclusion Criteria:

• Healthy (No neurological, cardiovascular or musculoskeletal disorders of any kind)
• No prior knowledge of the concept of mental fatigue
• No medication
• Non-smoker

Exclusion Criteria:

• Injuries of any kind in the past 6 months
• 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 ≥ 2.59 on the Burn out assessment tool (BAT)
• Suffering from high general fatigue, indicated by a score of >59 on the Multidimensional fatigue inventory (MFI)
• Suffering from depression, indicated by a score of >16 on the Beck depression inventory-II (BDI-II)
• 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