Mental Fatigue Negatively Impacts Cognitive and Physical Performance Outcomes: A Large-Scale Randomized Crossover Trial

Introduction: Mental fatigue is a change in psychobiological state caused by prolonged periods of demanding cognitive activity and has been observed to decrease whole-body endurance performance [1-5]. Recently a decreased resting-state cerebral blood-flow in the fronto-parietal cortex in the heat compared to in thermoneutral temperature was observed [6], raising the question whether mental fatigue may be even more detrimental for wholebody endurance performance in the heat. In normal ambient temperatures, performancedecrements of 5% [2] and 2% [4] have been observed in self-paced time trials (TT) due to mental fatigue.  Aim: To examine the effect of mental fatigue on a subsequent whole-body endurance performance and brain activity in the heat.  Methods: In 30°C and 30% relative humidity, ten endurance-trained male athletes (Age: 22 ± 3y; W max : 332 ± 41W; PL 3 [7]) completed two experimental trials in a single blind, randomized, cross-over design. A 5min Flanker was completed preceding and immediately following a 45min Stroop task [mental fatigue (MF)] or watching a documentary [control (C)]. Thereafter subjects cycled for 45min at a fixed pace equal to 60% Wmax, immediately followed by a self-paced TT in which they had to produce a fixed amount of energy (equal to cycling 15min at 80% W max ) as fast as possible. In the TT subjects started at 80% of their Wmax and were free to in- or decrease the resistance as desired from outset. Electroencephalographic measures (32 electrodes) were recorded continuously during the cognitive tasks. Power output, heart rate, blood lactate, core and skin temperature, thermal sensation, ratings of perceived exertion, NASA-TLX and mental fatigue-VAS-scale (M-VAS) were assessed throughout the protocol.  Results: Electroencephalographic (P3b-amplitude decreased and I±1-activity increased (p<0,05; fig. 1)) and perceptual (M-VAS increased (p<0,05)) measures were significantly altered in the Stroop compared to during the documentary. M-VAS was also significantly increased in the first 15min of the fixed intensity part of the physical performance. The induced mental fatigue did however not influence any physiological (heart rate, blood lactate, core or skin temperature) or perceptual (ratings of perceived exertion and thermal sensation) measure during the fixed intensity part. TT-time also did not differ between conditions (MF: 906 ± 30s, C: 916 ± 29s; Fig. 2). Individually three participants performed worse when mentally fatigued, four better and three replicated the same TT-time within a 5s-marge in both conditions (Fig. 2).  Conclusion: Although a mild mental fatigue was induced in the heat, no negative effect was observed on physiological, perceptual or behavioral measures during the fixed intensity part or the TT. There are three possible explanations for these results. Firstly, the mild mental fatigue was insufficient to alter endurance performance and/or endurance trained athletes are resistant to the negative effects of mental exertion on subsequent endurance performance [8]. Another plausible explanation is that mild mental fatigue does not reduce endurance performance when the brain is already stressed by a hot environment when the brain is already stressed by a hot environment.

Electrophysiological impact of mental fatigue on brain activity during a bike task: A wavelet analysis approach

It has been shown that the mental fatigue induced by prolonged self-regulation increases perception of effort and reduces performance during subsequent endurance exercise. However, the physiological mechanisms underlying these negative effects of mental fatigue are unclear. The primary aim of this study was to test the hypothesis that mental fatigue exacerbates central fatigue induced by whole-body endurance exercise. Twelve subjects performed 30 min of either an incongruent Stroop task to induce a condition of mental fatigue or a congruent Stroop task (control condition) in a random and counterbalanced order. Both cognitive tasks (CTs) were followed by a whole-body endurance task (ET) consisting of 6 min of cycling exercise at 80% of peak power output measured during a preliminary incremental test. Neuromuscular function of the knee extensors was assessed before and after CT, and after ET. Rating of perceived exertion (RPE) was measured during ET. Both CTs did not induce any decrease in maximal voluntary contraction (MVC) torque (p = 0.194). During ET, mentally fatigued subjects reported higher RPE (mental fatigue 13.9 ± 3.0, control 13.3 ± 3.2, p = 0.044). ET induced a similar decrease in MVC torque (mental fatigue –17 ± 15%, control –15 ± 11%, p = 0.001), maximal voluntary activation level (mental fatigue –6 ± 9%, control –6 ± 7%, p = 0.013) and resting twitch (mental fatigue –30 ± 14%, control –32 ± 10%, p < 0.001) in both conditions. These findings reject our hypothesis and confirm previous findings that mental fatigue does not reduce the capacity of the central nervous system to recruit the working muscles. The negative effect of mental fatigue on perception of effort does not reflect a greater development of either central or peripheral fatigue. Consequently, mentally fatigued subjects are still able to perform maximal exercise, but they are experiencing an altered performance during submaximal exercise due to higher-than-normal perception of effort.

The aim of this study was to test the effects of mental exertion involving response inhibition on pacing and endurance performance during a subsequent 5-km running time trial. After familiarization, 12 physically active subjects performed the time trial on a treadmill after two different cognitive tasks: (i) an incongruent Stroop task involving response inhibition (inhibition task) and (ii) a congruent Stroop task not involving response inhibition (control task). Both cognitive tasks were performed for 30 min. Neither the inhibition nor the control task induced subjective feelings of mental fatigue. Nevertheless, time trial performance was impaired following the inhibition task (24.4 ± 4.9 min) compared to the control task (23.1 ± 3.8 min) because of a significant reduction in average running speed chosen by the subject. The response inhibition task did not affect pacing strategy, which was negative in both conditions. Heart rate and blood lactate responses to the time trial were not affected by the inhibition task, but subjects rated perceived exertion higher compared to the control condition (13.5 ± 1.3 vs 12.4 ± 1.3). These findings show for the first time that 30 min of mental exertion involving response inhibition reduces subsequent self-paced endurance performance despite no overt mental fatigue. The impairment in endurance performance observed after the incongruent Stroop task seems to be mediated by the higher perception of effort as predicted by the psychobiological model of endurance performance.

A cross-sectional comparison of performance, neurophysiological and MRI outcomes of responders and non-responders to fampridine treatment in multiple sclerosis – An explorative study

ABSTRACTThis study investigated the effects of a mentally fatiguing test on physical tasks among elite cricketers. In a cross-over design, 10 elite male cricket players from a professional club performed a cricket run-two test, a Batak Lite reaction time test and a Yo-Yo-Intermittent Recovery Level 1 (Yo-Yo-IR1) test, providing a rating of perceived exertion (RPE) after completing a 30-min Stroop test (mental fatigue condition) or 30-min control condition. Perceived fatigue was assessed before and after the two conditions and motivation was measured before testing. There were post-treatment differences in the perception of mental fatigue (P < 0.001; d = −7.82, 95% CIs = −9.05–6.66; most likely). Cricket run-two (P = 0.002; d = −0.51, 95% CIs = −0.72–0.30; very likely), Yo-Yo-IR1 distance (P = 0.023; d = 0.39, 95% CIs = 0.14–0.64; likely) and RPE (P = 0.001; d = −1.82, 95% CIs = −2.49–1.14; most likely) were negatively affected by mental fatigue. The Batak Lite test was not affected (P = 0.137), yet a moderate (d = 0.41, 95% CIs = −0.05–0.87) change was likely. Mental fatigue, induced by an app-based Stroop test, negatively affected cricket-relevant performance.

The purpose of this study was to investigate the effects of mental fatigue, characterized by a subjective feeling of tiredness, on the development of neuromuscular fatigue during a 4-km cycling time trial (4-km TT). Eight recreationally trained male cyclists performed a 4-km TT after either performing a prolonged cognitive task (mental fatigue) or after viewing emotionally neutral documentaries (control). The neuromuscular function of the knee extensors was assessed using electrical nerve stimulation at baseline, before (pre-TT), and after (post-TT) the 4-km TT. Rating of perceived exertion (RPE) and physiological variables were periodically measured during 4-km TT. Subjective ratings of fatigue increased significantly only after a prolonged cognitive task (P = 0.022). Neuromuscular function at baseline was similar between conditions and remained unchanged at pre-TT. Time to complete the 4-km TT was similar between control (376 ± 27s) and mental fatigue (376 ± 26s). There was no significant difference between conditions for RPE, [Formula: see text], [Formula: see text], and HR throughout the exercise. The 4-km TT-induced similar decrease (from baseline to post-TT) in maximal voluntary contraction (mental fatigue - 11 ± 10%, control - 16 ± 12%), twitch force (mental fatigue - 26 ± 16%, control - 24 ± 17%), and voluntary activation (mental fatigue - 5 ± 7%, control - 3 ± 2%) for both conditions. Mental fatigue induced by prolonged cognitive task does not impair performance nor alter the degree of central and peripheral fatigue development during self-paced exercise in recreationally trained cyclists.

To examine the effects of caffeine ingestion on physiological and perceptual responses in mentally fatigued individuals. Eight male physically active subjects completed four cycling constant-workload tests in four experimental conditions at 80% of maximal power output: control (C), mental fatigue (MF), mental fatigue plus caffeine ingestion (5mg/kg) (MF-CAF), and mental fatigue plus placebo (MF-PLA). The mental fatigue was induced by a continuous performance task A-X version (AX-CPT). Before and after the AX-CPT, the profile of mood state (POMS) and blood samples for lactate measurement were collected. Oxygen consumption ([Formula: see text]), rating of perceived exertion (RPE), and electromyography (EMG) activity were measured during the cycling test. The time to exhaustion in C, MF, MF-PLA, and MF-CAF were 251±30, 222±23, 248±28, and 285±42s, respectively. Delta values (corrected by C condition) were higher in MF-CAF than MF (P=0.031). MF-CAF reported higher Vigor scores when compared with C (P=0.046) and MF (P=0.020). RPE at the first minute was significantly higher in MF-PLA than in C (P=0.050); at the second minute, RPE was higher in MF-PLA than in C (P=0.049) and MF-CAF (P=0.048). EMG activity was not different between the conditions. Caffeine ingestion increased approximately 14% endurance performance after the induction of mental fatigue. This effect was accompanied by a tendency to improvement in mood state (i.e., vigor). Therefore, caffeine ingestion can promote a beneficial effect on endurance performance in mentally fatigued individuals.

BackgroundMental fatigue is a psychobiological state characterized by a feeling of tiredness or lack of energy after performing cognitive activities. Recently, studies have found that prolonged use of social media can cause mental fatigue and consequently impair decision-making performance in athletes. On the other hand, caffeine may counteract mental fatigue by antagonizing adenosine. Therefore, this study aimed to analyze the effect of caffeine on the attack decision-making skill of trained beach volleyball players after prolonged cognitive effort by using social media on smartphones.MethodsTwelve trained young male beach volleyball players (Agemean: 18.38 ± 1.49 years old; Heightmean: 179.83 ± 7.54 cm; Body massmean: 73.14 ± 16.42 Kg) were recruited to a randomized, single-blind, crossover pilot study. Participants performed a beach volleyball task on low-dose caffeine (CAF: 3 mg/kg) or placebo (PLAC: crystallized cellulose) conditions after cognitive effort by social media use. In both conditions, participants used social media for 30 min and took capsules (CAF or PLAC, without identifying the type of capsule) 60 min before the beach volleyball task. Mental fatigue was assessed by visual analog scale and executive function by Stroop task (accuracy and response time). The Game Performance Assessment Instrument (GPAI) was used to assess attack decision-making skills through video recordings.ResultsThe subjective perception of mental fatigue increased only in the CAF condition (p = 0.018), and Stroop task performance was not different for all variables analyzed in both conditions (p > 0.05). Finally, the decision-making skill was not different between situations in attack (p = 0.890; d = 0.054) or counterattack (p = 0.617; d = 0.141).ConclusionsAt similar levels of mental fatigue, low-dose caffeine was not superior to placebo in improving attack decision-making. Considering the limitations of time and sample size, the results must be interpreted with caution.Trial registration numberBrazilian Clinical Trial Register (RBR-2yyd8jb). Registered 01 January 2024 (Retrospectively registered).

Acute carbohydrate (CHO) supplementation has consistently been shown to positively affect prolonged (> 60–90 min) moderate intensity endurance performance. In addition to substrate availability, prolonged endurance performance may be influenced by central fatigue as reflected by ratings of perceived exertion (RPE). Central fatigue may be mediated by cognitive and physiological factors such as motivation and endogenous opioids, respectively. Endogenous opioids are released during exercise and have been shown to decrease RPE, but to our knowledge no study to date has investigated the effects of supplementation designed to increase endogenous opioid activity on exercise performance and RPE. Lemongrass (cymbopogon citratus) has been shown to have antinoceceptive effects, possibly mediated by enhanced endogenous opioid activity. PURPOSE: To compare the effects of sports drinks without (CO) and with lemongrass (LG) on exercise performance and RPE. METHODS: Following a familiarization trial, 10 experienced male cyclists (25 ± 5 yr, 51.2 ± 5.7ml/kg/min VO2peak) completed two 40-km time trials on a cycle ergometer while consuming the CO and LG drinks in randomized order and double-blind fashion. The time trials were separated by a week and the CO and LG drinks consisted of 6 and 3% CHO, respectively. Subjects consumed 250 mL of the assigned drink immediately prior to and at each 20% completed segment (∼ every 15 min) throughout the test. Subjects were instructed to provide a maximal sprint effort over the final 1 km of the time trial. Time, power, speed, RPE and HR were recorded at each 20% completed segment. RESULTS: Subjects rode at approximately 82% of maximal HR during the time trials. No significant differences were found between the CO and LG drinks in total time (74.1 ±3.7 vs. 74.6 ±3.6 min), power (189.4 ±25.4 vs. 185.7 ± 25.4 W), speed (31.1 ± 3.8 vs. 32.3 ± 1.6km/h), HR(153 ± 11 vs. 151 ± 13 b/pm), or RPE (13.4 ± 1.0 vs. 12.9 ± 0.8). Similarly, there were no significant differences between drinks in any of the measured variables at any of the 20% completed segments or the final 1-km sprint. CONCLUSION: Lemongrass supplementation during endurance exercise may compensate for reduced CHO intake, but does not appear to do so by reducing RPE.

Frank, E, Ben-Zeev, T, Weissman, I, Binman, L, Ostfeld, I, Harel, N, and Hoffman, JR. The effect of an American football practice on physical and cognitive performance and recovery. J Strength Cond Res 39(11): 1169-1176, 2025-This study examined the effects of the first full-contact American football practice on cognitive and physical performance and recovery during a 36-hour period. Twelve male athletes from the Israeli Football League volunteered to participate in a study representing the initial full-contact football practice. Cognitive performance was assessed using the Sports Concussion Assessment Tool Fifth Edition and Stroop tests. Physical performance assessments included the isometric mid-thigh pull, vertical jump power, and reactive agility. Assessments occurred before practice (PRE), immediately postpractice (IP), 24 hours postpractice (D1), and 36 hours postpractice (D2). Blood samples were obtained to assess myoglobin, and brain-derived neurotrophic factor (BDNF), testosterone (T), and cortisol (C). T and C measures were obtained at PRE only to provide an indication of the baseline anabolic/catabolic ratio on the recovery response. Results revealed that physical performance measures, including peak force and rate of force development (RFD), showed significant declines IP, and remained impaired at D2. In contrast, cognitive function demonstrated improvements over time, with significant increases in acute memory, concentration, and delayed memory at D2. The testosterone-to-cortisol ratio was correlated ( r = 0.704, p = 0.034) with changes in RFD max , Myoglobin concentrations were significantly elevated at IP, reflecting the muscle damaging effects of the practice. No changes were observed in BDNF concentrations. These findings indicate that the initial full-contact football practice induces neuromuscular impairments for at least 36 hours. However, cognitive performance demonstrated a different recovery trajectory, improving over time. Understanding these recovery patterns may provide insight into optimizing training load management and recovery strategies during initial football training.

Background/Objectives: Creatine monohydrate (CrM) supplementation is well-established for enhancing physical performance and accelerating recovery in several sporting contexts. However, beyond these traditional performance benefits, its effects on sleep metrics and cognitive function have not been thoroughly investigated. This investigation aimed to determine the effect of a loading phase of CrM on sleep metrics, physical performance, psycho-cognitive aspects, and recovery in physically active men. Methods: In a randomized, double-blind, placebo-controlled crossover design, 14 physically active men ingested 20 g/day of CrM or placebo (PL) for 7 days, during which their habitual exercise routines were maintained and standardized across both intervention phases. Sleep metrics were monitored throughout the interventions using wrist-worn actigraphy. On the day following the completion of each supplementation phase, participants rated their sleep quality using the Sleep Subjective Quality (SSQ) scale, and the Hooper questionnaire was used to monitor participants’ well-being status. Physical performance was assessed using the 5 m shuttle run test (5mSRT), which measured total distance (TD), best distance (BD), performance decrement (PD), fatigue index (FI), and the rating of perceived exertion (RPE). Affective valence was determined using the feeling scale (FS) and cognitive function was evaluated using the digit cancellation test (DCT). Recovery and muscle soreness perceptions were evaluated at multiple time points (pre-exercise, 5 min, 24 h, 48 h, and 72 h post-exercise) using the perceived recovery status (PRS) and the delayed onset muscle soreness (DOMS) scales, respectively. Results: During the supplementation, CrM improved sleep quality compared to PL, as measured with the SSQ scale (d = 0.81, p = 0.009), and was associated with an earlier in-bed time (r = 0.60; p = 0.026). However, CrM did not affect sleep latency (t = 0.98; p = 0.35), sleep efficiency (t = 0.018; p = 0.98), or total sleep time (t = 0.25; p = 0.81). After the supplementation phase, CrM resulted in significantly lower muscle soreness scores, as measured by the Hooper questionnaire (d = −0.59; p = 0.046), improved cognitive performance on the DCT (d = 0.77; p = 0.013), and enhanced TD (r = 0.88; p < 0.001) and BD (r = 0.76; p < 0.05) during the 5mSRT. However, CrM did not significantly affect other exercise-related measures such as RPE, fatigue index (FI), or performance decrement (PD) during the 5mSRT, nor did it alter other subjective recovery scales compared to PL, up to 72 h following the end of the supplementation phase (all p > 0.05). Conclusions: A 7-day CrM loading protocol improved subjective sleep quality during the supplementation phase, enhanced cognitive performance, and increased physical output during high-intensity intermittent exercise. CrM also reduced muscle soreness, but did not significantly affect objective sleep parameters, or recovery markers up to 72 h post-exercise. These findings suggest that CrM may offer additional benefits beyond its traditional ergogenic role. Trial Registration: This trial was registered on 18 September 2023 at the Pan African Clinical Trials Registry (PACT) (identifier: PACTR202309597156293).

Normalization is a method used to account for body mass in clinical practice and research. It is unclear if thismethod will improve the correlation between muscle cross-sectional area (CSA) and physical performance. We examinedthe correlations between quadriceps muscle morphology parameters and physical performance outcomes in older women.Material and methods: Twenty older women participated in this study. Ultrasound imaging was used to measure quadricepsmuscle CSA and echo intensity. Muscle CSA was expressed as an absolute value (cm2) and as a relative value normalized tobody mass (cm2/kg). Physical performance was assessed from timed up-and-go and 6-min walk tests. Relative CSAwas significantly related to timed up-and-go scores (r=-0.489, p=0.029) and 6-min walking speed (r=0.606, p=0.005), whereasabsolute CSA was not significantly associated with these performances (r=-0.231, p=0.327 and r=0.373, p=0.105). There wasa significant correlation between absolute CSA and body mass (r=0.456, p=0.043). There were also significant correlationsbetween echo intensity and timed up-and-go scores (r=0.556, p=0.011) and 6-min walking speed (r=-0.484, p=0.031). Our study showed that relative CSA correlated better than absolute CSA with physical performance. These findingssupport the need to normalize measurements of muscle CSA to body mass in older adults.

Purpose: To quantify the evolution of mental fatigue during an official padel competition. Also, to test the influence of gender on mental fatigue, and the correlation between fatigue, effort perceptions and motivation. Method: Mental load and fatigue, motivation and ratio of perceived exertion of 18 semi-professional padel players (11 males, Mage = 33.68, SDage = 8.36, and 7 females, Mage = 30.70, SDage = 2.36) were quantified with Likert’s scales after three official matches. Repeated measures of ANOVA, with gender like a co-variable, pairwise comparisons when significance was detected and paired t-test when significance was not detected were performed. Pearson’s test was performed to clarify the relation between variables. Results: a significant main effect in repeated measures appear for mental fatigue, without gender differences (F = 8.85; p = .02 in males; F = 5.70; p = .03 in females). This main effect has not been observed for mental load (F = .08; p = .86 in males; F = .36; p = .71 in females) neither effort perception (F = .16; p = .83 in males; F = .43; p = .66 in females), in both genders. Bivariate correlations also suggested that higher levels of mental fatigue and motivation increase the effort perceptions. Conclusion: Play successive padel matches produces an accumulation of mental fatigue that increase the subjective feelings of mental fatigue. This only occurs between matches played the same day. Players with higher levels of motivation report higher effort perceptions. They might imply more resources during matches.

Individuals experience mental fatigue during or after prolonged periods of cognitive activity. The aim of the present study was to investigate the effect of mental fatigue on detection of changes at the preattentive stage in the visual system by recording visual mismatch negativity of event-related potential components. Twenty-four students who volunteered for the study were divided randomly into either a mental fatigue group or a control group. Participants in the mental fatigue group were asked to perform an AX continued practice test for 2.5 h while the control group rested in the lab for 2.5 h. Then, subjective fatigue and mood state were measured by the Subjective Fatigue Symptom Questionnaire and the Profile of Mood States, respectively. Preattentive processing was evaluated as well by assessing the duration of the passive oddball task both before and after manipulation. In participants who performed the AX continued practice test, we observed a significant increase in feelings of fatigue and tiredness, and negative emotion. In these same participants, we observed a significant decrease in attention and positive emotion. This indicates that continuous cognitive operation induces mental fatigue. In addition, we found that the visual mismatch negativity amplitude was significantly reduced in participants with mental fatigue, implying that visual deviant/change detection is affected by mental fatigue. These results suggest that preattentive change detection and automatic processing decline as a result of mental fatigue.