Search Results (53)

Reaction time (RT) is widely used as a fundamental indicator of central nervous system processing speed. Numerous studies have shown that RT increases with age, generally interpreted as a decline in information processing efficiency. However, most previous studies have focused on absolute RT values, and it remains unclear whether aging also alters the relative relationships between responses under different task conditions. The present study investigated whether aging affects the relative difference between inside and outside pedal reaction times in a Foot Psychomotor Vigilance Test (Foot PVT). A total of 44 participants were analyzed, including 20 younger adults (24 ± 3 years) and 24 older adults (73 ± 5 years). Participants responded to visual stimuli by pressing either the left or right pedal with the right foot. The difference between inside and outside RT (dRT) was calculated for each participant as an index of relative response structure. Group comparisons and correlation analyses were conducted to examine associations with age, height, physical activity level (PAL), and sleep-related factors. As expected, RTs were consistently longer in older adults across conditions. In contrast, dRT did not differ significantly between younger and older groups, with negligible effect sizes (|d| < 0.1). Furthermore, dRT showed no significant correlations with height, PAL, or sleep-related indices. These findings indicate that while aging affects the overall speed of motor responses, the relative temporal structure between response conditions is preserved. This dissociation between global slowing and stable response structure may represent a fundamental characteristic of neuromotor aging. Full article

Background/Objectives: Creatine is a supplement that, beyond its physiological effects, has been shown to have positive effects on cognitive abilities. In our previous study, we showed that a single dose of 0.35 g/kg creatine induces changes in brain metabolism during sleep deprivation and reduces deterioration in cognitive performance. The present study investigates whether supplementation of a lower dose is associated with cognitive effects during sleep deprivation, focusing exclusively on cognitive performance outcomes. Methods: Twenty-nine healthy subjects performed cognitive tests at the evening baseline and 3, 5.5, and 7.5 h after receiving a single dose of creatine monohydrate (0.2 g/kg) or a placebo during a total of 21 h of sleep deprivation (SD). Results: The results show a mitigating effect of creatine on sleep deprivation-induced deterioration in logical and numerical tasks, language-related processing speed, and the Psychomotor Vigilance Test (PVT). Compared to males, females benefit more in logic, PVT and processing speed in language and logic tasks. Conclusions: Our results show that a dose of 0.2 g/kg creatine is associated with a reduced deterioration in cognitive performance during sleep deprivation. Although the effect is less pronounced than with a high dose of 0.35 g/kg, there is still an improvement of up to 12%. Full article

Background/Objectives: Adolescence is a critical period for executive function (EF) maturation. While sleep and physical activity (PA) are key lifestyle factors, their longitudinal impact on EF in ecologically valid settings is insufficiently characterised. This study examined the associations between objectively measured sleep duration, daily steps, and EF performance across one academic year (~9 months). Methods: A longitudinal study was conducted with 168 Spanish adolescents (13–16 years). Sleep duration and daily steps were monitored using Fitbit Charge 6 wearables for 7-day periods at baseline (M1; September 2024) and follow-up (M2; June 2025). EFs were assessed using three validated tasks: Stroop (inhibitory control), Psychomotor Vigilance Task-Brief (PVT-B; sustained attention), and Paced Auditory Serial Addition Test (PASAT; working memory). Linear Mixed Models (LMM) were employed to analyse the effects of the fixed factors (i.e., Group and Time), and their interactions. Results: PA, but not sleep duration, significantly predicted executive performance. The High_PA group demonstrated faster reaction times in inhibitory control (p = 0.007) and significantly fewer attentional lapses in sustained attention (p = 0.014). In contrast, sleep duration showed no significant main effects on EF domains (p > 0.05). Regression analyses confirmed that higher daily steps predicted faster reaction times in inhibitory control in the total sample (r = −0.173, p = 0.002), although an unexpected positive association was observed in the Low_PA group for inhibitory control, warranting cautious interpretation. Conclusions: These findings suggest that habitual PA is associated with better EF performance in adolescents, whereas sleep duration alone (without considering timing or variability) showed no significant associations with cognitive outcomes. Sensitivity analyses using clinically informed thresholds and continuous standardised predictors confirmed the robustness of these findings. Full article

This study examined the acute effects of electric lighting parameters (illuminance and correlated color temperature (CCT)) on vigilance and subjective alertness in older adults with mild cognitive impairment (MCI), with direct relevance to architectural lighting design in senior-care and rehabilitation settings. A within-subject experimental design was used with nine older adults diagnosed with MCI. Participants completed the NASA Psychomotor Vigilance Task (PVT) under four lighting conditions: 350 lux at 2700 K, 350 lux at 6500 K, 478 lux at 2700 K, and 478 lux at 6500 K. To account for repeated testing, practice-related changes across sessions were explicitly considered in the interpretation of outcomes. Subjective measures included the Karolinska Sleepiness Scale (KSS), the Groningen Sleep Quality Questionnaire, and two lighting evaluation surveys. Data analyses included paired-sample t-tests, effect sizes (Hedges’ g, η²), odds ratios, and confidence intervals. Across sessions, PVT performance improved overall, consistent with a practice effect. On Day 1 (350 lux), minimum reaction time did not differ between 2700 K and 6500 K; however, maximum reaction time was shorter under 6500 K, suggesting a selective reduction in extreme slow responses under cooler-spectrum light at baseline. On Day 2 (478 lux), minimum reaction time improved significantly under 6500 K, indicating faster responses under cooler-spectrum light when combined with higher illuminance and repeated exposure. False starts and lapses did not show consistent condition-dependent differences. Overall, cooler-spectrum light did not uniformly shift mean performance but instead appeared to stabilize performance by reducing extreme slow responses at baseline and enhancing rapid responses under higher illuminance with repeated exposure. These findings suggest that practice effects and spectral sensitivity jointly shape vigilance outcomes in older adults with MCI. From a building design perspective, the results support the potential value of tunable lighting (adjustable CCT and illuminance) as a non-pharmacological strategy to help sustain daytime alertness in senior-care and rehabilitation environments. Full article

Aim: This study compared the effects of standard evening smartphone restriction with an adapted intervention combining progressive restriction, psychoeducational guidance, and pre-sleep relaxation on sleep, psychological state, cognitive performance, and physical performance in physically active physical education students with moderate-to-high nomophobia. Methods: Thirty participants (age 21.9 ± 1.2 years; intermediate chronotype) completed a randomized controlled trial consisting of a 7-day baseline period, a 14-day intervention phase, and post-intervention assessments. The standard group (n = 15) implemented a 2-h pre-bedtime smartphone restriction combined with general sleep hygiene guidance. The adapted group (n = 15) followed a progressive restriction protocol (30→60→120 min) supplemented with psychoeducational guidance targeting smartphone-related anxiety and a nightly slow-paced breathing routine. Objective sleep parameters were quantified using wrist-worn actigraphy. Subjective sleep quality, pre-sleep anxiety, and stress were assessed using visual analog scales. Cognitive performance (psychomotor vigilance task and choice reaction time) and physical performance (vertical jumps and agility) were evaluated at both morning and afternoon time points. Results: The adapted intervention produced significantly greater improvements in sleep efficiency (time × group: F(1,28) = 6.84, p = 0.014, ηp² = 0.20; d = 0.78) and sleep onset latency (F(1,28) = 5.97, p = 0.021, ηp² = 0.18; d = 0.72) compared with standard restriction. Significant reductions were also observed in pre-sleep anxiety (F(1,28) = 7.12, p = 0.012, ηp² = 0.20; d = 0.81) and stress (F(1,28) = 6.45, p = 0.017, ηp² = 0.19; d = 0.74). Cognitive performance showed significant time × group × time-of-day interactions, with improvements during afternoon assessments in psychomotor vigilance (F(1,28) = 7.48, p = 0.011; d = 0.83) and choice reaction time (F(1,28) = 6.89, p = 0.014; d = 0.79) exclusively in the adapted group. Physical performance outcomes remained stable across interventions. Conclusions: Progressive smartphone restriction combined with psychoeducational strategies and pre-sleep relaxation yields clinically meaningful improvements in sleep continuity, psychological arousal, and afternoon cognitive performance, exceeding the benefits achieved through behavioral restriction alone. Full article

This study examined the effects of cognitive fatigue on repeated sprint ability (RSA), neuromuscular performance, and vigilance in physically active young adults (N = 28, 16 males, 12 females; mean age = 20.6 ± 1.4 years). Participants were randomly assigned to a mental fatigue (MF) or control (CON) group and completed baseline and post-condition assessments following a cognitively demanding or neutral task. Repeated sprint performance significantly declined in the MF group, as shown by increased RSA mean time (Δ = 0.432 s, p < 0.001) and total time (Δ = 4.331 s, p < 0.001), with no statistically significant change observed in the CON group. Countermovement jump height remained unaffected; however, repeated jump ability showed impaired contact time (Δ = 0.084 s, p = 0.007) in the MF group. Psychomotor vigilance significantly deteriorated under mental fatigue, as evidenced by slower reaction times (Δ = 119.71 ms, p < 0.001) and increased lapses (Δ = 2.86, p < 0.001). Subjective ratings confirmed elevated perceived exertion (Δ = 0.79, p = 0.002) and mental fatigue (Δ = 8.00, p < 0.001) in the MF group, without changes in motivation. These findings may demonstrate that cognitive fatigue impairs both physical and cognitive performance, even in trained individuals. Full article

This study investigated the physiological effects of seat vibration during prolonged sitting in a simulated autonomous driving environment. Eleven healthy participants (3 young adults and 8 older adults) viewed a 120-min highway driving video under two conditions: rhythmic seat vibration (2 Hz, mimicking natural respiration) and no vibration. Physiological and behavioral metrics—including Psychomotor Vigilance Task (PVT), seat pressure distribution, heart rate variability (HRV), body acceleration, and skin temperature—were assessed across three phases. Results demonstrated that seat vibration significantly enhanced parasympathetic activity, as evidenced by increased HF power and decreased LF/HF ratio (p < 0.05), suggesting reduced autonomic stress. Additionally, seated posture remained more stable under vibration, with reduced asymmetry and sway, while the no-vibration condition showed time-dependent postural degradation. Interestingly, skin surface temperature was lower in the vibration condition (p < 0.001), indicating a possible thermoregulatory mechanism. In contrast, PVT performance revealed more false starts in the vibration condition, particularly among older adults, suggesting that vibration may not enhance—and could slightly impair—cognitive alertness. These findings suggest that low-frequency seat vibration can support physiological stability and postural control during prolonged sedentary conditions, such as in autonomous vehicles. However, its effects on vigilance appear limited and age-dependent. Overall, rhythmic vibration may contribute to enhancing passenger comfort and reducing fatigue-related risks, particularly in older individuals. Future work should explore adaptive vibration strategies to balance physiological relaxation and cognitive alertness in mobility environments. Full article

Objective: Mental fatigue (MF) worsens soccer performance. Further knowledge is needed to understand MF’s effects on soccer players and its underlying mechanisms. Our aim was to analyze the subjective, objective, and neural MF-related outcomes induced by different type of tasks. Methods: A randomized crossover experimental design with repeated measures was used. Thirteen amateur soccer players (M_age = 23 ± 5.43) completed three conditions: cognitive (30 min. Stroop.), physical (30 min. cycling), or combined (30 min. Stroop while cycling). Ratings of mental fatigue (measured via the Visual Analogue Scale), electroencephalographical signals (electroencephalography), and psychomotor performance (Brief-Psychomotor Vigilance Test) were measured pre- and post-condition. Soccer-related decision-making (TacticUP^® test) was assessed post-condition. Results: Linear Mixed Models analysis revealed increments in perceived mental fatigue in all conditions, especially cognitive (p = 0.004) and combined (p < 0.0001) conditions. Psychomotor performance worsened, especially for cognitive (p = 0.039) and combined (p = 0.009) conditions. The Individual Alpha Peak Frequency was lower after the cognitive task (p = 0.040) and compared with the physical task (p = 0.021). The Alpha midline power increased after the cognitive task in the central-frontal (p = 0.047) and central-posterior brain regions (p = 0.043). Conclusions: Cognitive and combined conditions were found to be more mentally demanding and fatiguing than single physical tasks. This was also reflected by an impaired reaction time. Based on the neural activity recorded, the performance impairments caused by mental fatigue were caused by reduced brain readiness (i.e., a lower Alpha Peak Frequency). However, non-significant changes were found in soccer-related decision-making. Coaches should consider the type of training tasks they recommend in light of their different effects on mental fatigue and performance. Full article

This study aimed to investigate the effects of mental fatigue on physical and cognitive performance (lower-limb power, isometric and handgrip strength, and psychomotor vigilance). Twenty-two physically active young adults (12 males, 10 females; M_age = 20.82 ± 1.47) were randomly assigned to either a Mental Fatigue (MF) or Control group (CON). The MF group showed a statistically significant (p = 0.019) reduction in non-dominant handgrip strength, declining by approximately 2.3 kg (about 5%), while no such change was observed in the CON group or in dominant handgrip strength across groups. Reaction time (RT) was significantly impaired following the mental fatigue protocol: RT increased by 117.82 ms, representing an approximate 46% longer response time in the MF group (p < 0.001), whereas the CON group showed a smaller, non-significant increase of 32.82 ms (~12% longer). No significant differences were found in squat jump performance, indicating that lower-limb explosive power may be less affected by acute mental fatigue. These findings demonstrate that mental fatigue selectively impairs fine motor strength and cognitive processing speed, particularly reaction time, while gross motor power remains resilient. Understanding these effects is critical for optimizing performance in contexts requiring fine motor control and sustained attention under cognitive load. Full article

Objectives: With the advancement of modern society, people in cognitively demanding jobs are increasingly exposed to occupational stress. Prolonged and high-intensity cognitive activities are prone to inducing mental fatigue (MF), which adversely affects both psychological and physiological well-being, as well as task performance. Existing methods for inducing MF often demonstrate limited effectiveness due to insufficient cognitive load from overly simplistic tasks and the potential emotional disturbance caused by prolonged task duration. This study aims to explore a comprehensive cognitive task paradigm that integrates task complexity and time pressure, thereby developing a novel and effective method for inducing MF based on high mental workload (HMW) and the effects of time on task (ToT). Methods: Using convenience sampling, university students from a medical college were recruited as participants. The study was conducted in three steps. In the first step, we constructed a 1-back Stroop (BS) task paradigm by designing tasks with varying levels of complexity and incorporating time pressure through experimental manipulation. In the second step, the efficacy of the BS task paradigm was validated by comparing it with the traditional 2-back cognitive task in inducing HMW. In the third step, an MF induction protocol was established by combining the BS task paradigm with the ToT effect (i.e., a continuous 30 min task). Effectiveness was assessed using validated subjective measures (NASA Task Load Index [NASA-TLX] and Visual Analog Scale [VAS]) and objective behavioral metrics (reaction time and accuracy). Statistical analyses were performed using analysis of variance (ANOVA) and t-tests. Results: The BS task paradigm, which integrates complex cognitive abilities such as attention, working memory, inhibitory control, cognitive flexibility, and time pressure, demonstrated significantly higher NASA-TLX total scores, as well as elevated scores in mental demand, temporal demand, performance, and frustration scales, compared to the 2-back task. Additionally, the BS task paradigm resulted in longer reaction times and lower accuracy. As the BS task progressed, participants exhibited significant increases in mental fatigue (MF), mental effort (ME), mental stress (MS), and subjective feelings of fatigue, while the overall number of correct trials and accuracy showed a significant decline. Furthermore, reaction times in the psychomotor vigilance test (PVT) were significantly prolonged, and the number of lapses significantly increased between pre- and post-task assessments. Conclusions: The BS task paradigm based on complex cognitive abilities and time pressure could effectively induce an HMW state. Combined with the ToT effect, the BS paradigm demonstrated effective MF induction capabilities. This study provides a novel and reliable method for inducing HMW and MF, offering a valuable tool for future research in related fields. Full article

Sustained attention is a critical cognitive function, especially in contexts such as driving safety, where performance deterioration due to fatigue or drowsiness can have serious consequences. Although individual differences in sustained attention have been recognized and are known to decline with age, quantitative analyses considering sex and circadian timing are limited. In this study, we analyzed psychomotor vigilance task (PVT) data from 356 participants to investigate the effects of age, sex, and time of day on attention performance. Participants completed a 5-min PVT, and metrics including the reaction time (RT), minor lapses (MNLs, ≥5 ms), major lapses (MJLs, ≥8 ms), and false starts (FSs) were calculated. A general linear model was applied with sex and testing time (8:00–12:00, 13:00–16:00, 16:00–18:00) as fixed factors and age as a covariate. Stepwise multiple regression was also used to assess how well age, sex, and time of day explain performance. The RT showed significant differences by time and age (p < 0.001), with higher numbers of MNLs during morning sessions. Both sexes demonstrated significantly better performance in the afternoon compared to the morning. These results highlight the importance of controlling for the testing time in PVT-based experiments and underscore the measurable individual differences in sustained attention. Full article

Objective: Mental fatigue (MF) induced by prolonged cognitive tasks poses significant risks to postural stability, yet its effects on multi-sensory integration remain poorly understood. Method: This study investigated how MF alters sensory reweighting and postural control in 27 healthy young males. A 45 min incongruent Stroop task was employed to induce MF, validated via subjective Visual Analog Scale (VAS) scores and psychomotor vigilance tests. Postural stability was assessed under four sensory perturbation conditions (O-H: no interference; C-H: visual occlusion; O-S: proprioceptive perturbation; C-S: combined perturbations) using a Kistler force platform. Center of pressure (COP) signals were analyzed through time-domain metrics, sample entropy (SampEn), and Discrete Wavelet Transform (DWT) to quantify energy distributions across sensory-related frequency bands (visual: 0–0.1 Hz; vestibular: 0.1–0.39 Hz; cerebellar: 0.39–1.56 Hz; proprioceptive: 1.56–6.25 Hz). Results: MF significantly reduced proprioceptive energy contributions (p < 0.05) while increasing vestibular reliance under O-S conditions (p < 0.05). Time-domain metrics showed no significant changes in COP velocity or displacement, but SampEn decreased under closed-eye conditions (p < 0.001), indicating reduced postural adaptability. DWT analysis highlighted MF’s interaction with visual occlusion, altering cerebellar and proprioceptive energy dynamics (p < 0.01). Conclusion: These findings demonstrate that MF disrupts proprioceptive integration, prompting compensatory shifts toward vestibular and cerebellar inputs. The integration of nonlinear entropy and frequency-domain analyses advances methodological frameworks for fatigue research, offering insights into real-time sensor-based fatigue monitoring and balance rehabilitation strategies. This study underscores the hierarchical interplay of sensory systems under cognitive load and provides empirical evidence for optimizing interventions in high-risk occupational and clinical settings. Full article

Background: Mental fatigue can impair sport, exercise and cognitive performance. Warmup activities can improve performance when the individual is rested. However, their effectiveness when the individual is fatigued has yet to be established. The research objectives were to evaluate the effects of physical and combined physical plus cognitive warmup activities on subsequent sport, exercise, and cognitive performance when rested and fatigued by sleep restriction in athletes (Study 1) and older adults (Study 2). Methods: In Study 1, 31 padel players completed a padel performance test and Stroop task after physical and combined warmups when rested and fatigued by sleep deprivation. In Study 2, 32 older adults completed sit–stand, arm curl, walking, Stroop, and psychomotor vigilance tests after no warmup, physical warmup, and combined warmup when rested and fatigued by sleep deprivation. In both studies, combined warmups intermixed short-, medium-, or long-duration cognitive tasks between physical warmup activities. Mental fatigue was measured using visual analog scale ratings. Results: In both studies, sleep deprivation increased mental fatigue and impaired performance. In Study 1, relative to a physical warmup, padel and Stroop performance were improved by combined warmups (with short-to-medium cognitive tasks) when rested and fatigued. In Study 2, relative to no warmup, sit–stand, arm curl, walking, Stroop, and reaction time performance were improved by physical and combined warmups (with short-to-medium cognitive tasks) when rested and fatigued. Conclusions: The negative effects of sleep deprivation on sport, exercise, and cognitive performance were best mitigated by combined warmups with short-to-medium cognitive tasks. Combined warmups are effective countermeasures against the deleterious effects of mental fatigue on performance. Full article

Time-of-day and individual circadian variability influence cognitive performance, with later chronotypes being most compromised earlier in the day. On the other hand, moderate-intensity exercise has been shown to enhance cognitive function. We sought to evaluate the interplay among circadian rhythms, exercise, and cognitive performance in 22 students from the Uruguayan National Dance School, a population previously characterized as late chronotypes, attending a demanding morning schedule. We assessed sleep habits and physical activity patterns using self-report questionnaires and actigraphy. Before and after morning training, participants completed a psychomotor vigilance task (PVT) and a visual Stroop task (congruent and incongruent). The reaction speeds were lower early in the morning than at noon for all these tasks. We also found (1) a positive correlation between weekend sleep duration and PVT performance before training but not after; (2) a negative correlation between individual circadian phase and Stroop performance for both congruent and incongruent conditions after training but not before; and (3) a better Stroop performance after training for both congruent and incongruent conditions in dancers who engaged longer moderate-intensity exercise during training. Our findings suggest that regular morning training might help mitigate cognitive impairments experienced by dancers with later chronotypes in challenging morning scenarios. Full article

This study aimed to analyze how active versus passive rest periods after a warm-up influence performance in psychomotor vigilance tasks (PVT). Twenty amateur karate athletes participated in a randomized cross-over study consisting of two sessions with either a 20 min active rest involving kata techniques or passive rest. PVT was administered before and after these conditions to assess the changes in reaction time. The results revealed that the active rest condition significantly improved reaction times compared to both the passive rest condition (F(1,31) = 5.34, p = 0.03, η² partial = 0.14) and control condition (F(1,31) = 5.49, p = 0.02, η² partial = 0.15). No significant time-on-task effects were observed, F(4,120) = 2.31, p = 0.06, and there were no significant interactions between effort condition and time-on-task, F(4,120) = 1.89, p = 0.11). Participating in an active rest period post-warm-up improves cognitive performance in karate athletes, as evidenced by quicker reaction times in the PVT. This finding supports the use of active rest strategies (involving kata techniques) to maintain and improve cognitive readiness in young karate athletes. Full article