The main aim of this biomedical study is to determine the effect of moderate-intensity aerobic exercise, before and after an 8-hour workday and a combined work model, on the performance and efficiency of cognitive functions during mental work. There are lack of previous studies analysing the effects of different physical activity strategies on cognitive efficiency and investigating mental fatigue resistance. Limited research in this area shows that the mechanism of the effect of physical activity on mental fatigue resistance is still unclear. This research will aim to investigate different physical activity strategies, such as combined work model and moderate intensity physical activity before and after office workday, and their impact on a mental and emotional fatigue, cognitive efficiency, sympathetic and parasympathetic systems and metabolic indicators during mentally demanding 8 h workday.
Prolonged sedentary behavior and sustained cognitive workload during typical office workdays contribute significantly to the onset of acute mental fatigue (Kunasegaran et al., 2023). This condition is linked to physiological mechanisms such as reduced cerebral blood flow, diminished glucose availability and transport to active brain regions (García et al., 2021; Kennedy \& Scholey, 2000), as well as hormonal alterations (Miyashita \& Williams, 2006; Wiehler et al., 2022). These changes negatively impact cognitive efficiency, motivation, and overall brain function (Kunasegaran et al., 2023; Tran et al., 2020). While existing evidence supports the positive influence of physical activity on physical and mental health (Calderwood et al., 2021; Jacquet et al., 2021), there remains a lack of research specifically examining how different physical activity strategies influence cognitive efficiency and resistance to mental fatigue. This study aims to address this gap by investigating the effects of various physical activity interventions, including a combined work-exercise model and moderate-intensity aerobic exercise performed either before or after an 8-hour mentally demanding workday. Outcomes will focus on mental and emotional fatigue, cognitive efficiency, autonomic nervous system activity (sympathetic and parasympathetic balance), and metabolic responses. By evaluating these parameters, the study seeks to clarify the potential of targeted physical activity strategies to enhance mental fatigue resistance and support cognitive performance in occupational settings. The findings are expected to contribute valuable insight into the development of effective workplace interventions that promote employee well-being, productivity, and resilience.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
60
During a simulated 8-hour mental work day, subjects will complete a set of cognitive tests (ANAM4, version 4; Vista Life Science, Norman, OK, USA) 8 times (1 session approximately 45 minutes), with a break of approximately 10 minutes after each session.
In one of the conditions, subjects will perform moderate intensity aerobic activity (cycle veloergometer) for 30 min before 8 hours simulated mental workday and after.
In one of the conditions, subjects will perform cognitive test during 8 hours simulated mental workday applying combined work model (they will work standing and sitting on a balance ball).
Institute of Sport Science and Innovations
Kaunas, Lithuania
RECRUITINGBody mass and body composition (kg)
Body mass and composition (in kilograms) will be evaluated using Tanita Body Composition Analyzer (Japan).
Time frame: 2 times in the mornings (day 1 and day 2) of each 3 conditions.
Height (m)
Height (in meters) will be measured using a Harpenden anthropometer set (Holtain Ltd, UK).
Time frame: 2 times in the mornings (day 1 and day 2) of each 3 conditions.
Brain hemodynamic response
To measure and evaluate hemodynamic response, a functional near-infrared (fNIRS) device NIRx NIRS Sport2 (Medical Technologies LLC-NIR-Scout, USA) with 8 near-infrared (NIR) radiation sources and 7 photodetectors will be used. The photodetectors record the relative changes in oxygen and oxygenated hemoglobin at 7.81 Hz for both wavelengths. The probes are placed at the manufacturer's specified locations to capture the hemodynamic response of the prefrontal cortex. Live recording will be monitored for 6 minutes.
Time frame: Before, immediately after the simulated mental workday, 3 hours after the simulated mental workday, and 12 hours recovery after a simulated mental workday in 3 conditions.
Cognitive performance
Automated Neuropsychological Assessment Metrics Test Set (ANAM4, version 4; Vista Life Science, Norman, OK, USA). 11 tests will be selected, reflecting the three main cognitive functions - memory, attention and executive function. 11 tests: Procedural RT, Memory search, Spatial processing simultaneous, Matching grids, Matching to sample, Stroop colour word test, Code substitution-learning and Code substitution-delayed, Running memory continuous performance, Continous performance test - traditional. To assess cognitive performance, during a simulated 8-hour mental work day, the subjects will complete a set of cognitive tests 8 times (1 session approximately 45 minutes), after each session there will be a break of approximately 10 minutes. Participants were familiarized with the test battery twice before the experiments.
Time frame: Day 1 in 3 different conditions, in 1 condition 8 times for 45 minutes.
Blood pressure (mmHg)
Systolic and diastolic blood pressure (in mmHg) will be measured using a blood pressure monitor (Biolight, Patient Monitor S10, Guangdong Biolight Meditech Co, Hamburg, Germany).
Time frame: 11 times during 1 condition (total 33 times).
Heart rate and heart rate variability (ms)
Heart rate (HR) will be recorded using a heart rate monitor (Polar H10, Kempele, Finland) with an electrode strap around the chest throughout the study. 5-min RR interval file will then be analyzed using Kubios HR Variability Analysis Software 2.0 (Biomedical Signal and Medical Image Analysis Group, Department of Applied Physics, University of Kuopio, Kuopio, Finland).
Time frame: During 1 condition rest measurements in the morning, during brain hemodynamic response (3 times during 1 condition), during every session of 8 hours simultaneous mental work day, total 3 conditions.
Glucose level (mmol/l)
Glucose level will be measured from capillary blood using Akray glucose analyzer (CONTOUR®PLUS ELITE; Basel, Switzerland). Capillary blood samples will be taken by a qualified medical professional (general practice nurse) at the LSU Institute of Sports Science and Innovation laboratory.
Time frame: 9 times during 1 condition (total 27 times).
Ketones level (mmol/L)
Ketones level will be measured from capillary blood using a ketone analyzer (The On Call® GK Dual; San Diego, CA; USA). Capillary blood samples will be taken by a qualified medical professional (general practice nurse) at the LSU Institute of Sports Science and Innovation laboratory.
Time frame: 9 times during 1 condition (total 27 times).
Lactate level (mmol/L)
Lactate levels will be measured using a lactate analyzer (Lactatte Pro 2, Arkray, Koji Konan-cho, Koka-shi, Japan). Capillary blood samples will be taken by a qualified medical professional (general practice nurse) at the LSU Institute of Sports Science and Innovation laboratory.
Time frame: 9 times during 1 condition (total 27 times).
Salivary cortisol concentration (µg/dl)
The saliva samples will be collected to measure cortisol level (in µg/dl) using an ELISA kits and a Spark multimode microplate reader (Tecan, Austria).
Time frame: 11 times during 1 condition (total 33 times).
Salivary testosterone concentration (µg/dl)
The saliva samples will be collected to measure cortisol level (in µg/dl) using an ELISA kits and a Spark multimode microplate reader (Tecan, Austria).
Time frame: 11 times during 1 condition (total 33 times).
Salivary female sex hormones concentration (pgmol/L)
The saliva samples will be collected to measure cortisol level (in µg/dl) using an ELISA kits and a Spark multimode microplate reader (Tecan, Austria).
Time frame: 11 times during 1 condition (total 33 times).
Biochemical urine analysis
The urine sample will be analyzed in the laboratory using a urine analyzer (PocketChem UA, PU-4010, Arkray, Koji, Konan-cho, Koka-shi, Japan). The analyzer will determine the concentrations of ketones.
Time frame: 2 times during 1 condition (total 6 times).
Pupil diameter (mm)
The dilation and contraction of the pupils of the test subjects' eyes will be recorded using a special camera (Gazepoint, Vancouver, Canada), which will be placed under the computer screen, in front of the subject.
Time frame: Before and 3 times during simulated 8 hours workday in 1 condition (total 12 times).
The psycho-emotional state: Dundee Stress State Questionnaire (DSSQ)
The psycho-emotional state of the subjects will be assessed using the Dundee Stress State Questionnaire (DSSQ). The DSSQ questionnaire will be used to assess the subjects' motivation in relation to the content of the task, performing a cognitive test battery during the mental work day. 15 questions will be used, e.g.: "the content of the task was interesting", "I wanted to do the task well compared to others", etc. The subject will have to mark the corresponding answers to each question, where 4 (strongly), 3 (very), 2 (a little), 1 (a little), 0 (not at all).
Time frame: Before and 8 times during simulated 8 hours workday in 1 condition (total 27 times).
The psycho-emotional state: the VAS scale
Motivation, mental fatigue and mind wondering will be assessed using a visual analogue scale (VAS). Subjects will mark their feelings on a 10 centimetres horizontal line from 0 ("completely unmotivated"; "not mentally tired"; "no mind wandering") to 100 ("maximum motivated"; "maximum mental fatigue"; "maximum mind wandering").
Time frame: Before and 8 times during simulated 8 hours workday in 1 condition (total 27 times).
The psycho-emotional state: Stanford sleepiness scale.
The Stanford Sleepiness Scale will be used to assess subjects' sleepiness. On this scale, subjects will mark their level of sleepiness from 1 "I feel active, efficient, lively, alert or awake" to 7 "I can no longer fight sleep, I will fall asleep quickly; thoughts are like dreams".
Time frame: Before and 8 times during simulated 8 hours workday in 1 condition (total 27 times).
Measurement of maximal aerobic capacity
The maximal aerobic capacity of the subjects will be measured in order to determine the average aerobic load, which will be applied in the study condition "aerobic activity ". The subjects will perform a consistently increasing load until complete fatigue on a bicycle ergometer (Lode B.V., Excalibur Sport, Groningen, Netherlands). Throughout the test, subjects will have their heart rate monitored using a chest strap heart rate monitor (Polar H10, Kempele, Finland). A spirometry system (Metalyzer 3B, Cortex, Leipzig, Germany) will be used to measure oxygen uptake (VO2). VO2max (maximum oxygen uptake) will be considered the highest oxygen uptake during any 15 s of exercise.
Time frame: Before.
Sleep quality assessment
Sleep (hours of total sleep and sleep stages) will be monitored using a Garmin wrist-worn watch (Vivo fit 4, UK).
Time frame: 3 days before each condition and during testings.
Physical activity assessment
Physical activity (steps per day) will be monitored using a Garmin wrist-worn watch (Vivo fit 4, UK).
Time frame: 3 days before each condition and during testings.
Biochemical urine analysis
The urine sample will be analyzed in the laboratory using a urine analyzer (PocketChem UA, PU-4010, Arkray, Koji, Konan-cho, Koka-shi, Japan). The analyzer will determine the concentrations of leukocytes.
Time frame: 2 times during 1 condition (total 6 times).
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