Prefrontal cortical activity during uneven terrain walking in younger and older adults.

Introduction: Walking in complex environments increases the cognitive demand of locomotor control; however, our understanding of the neural mechanisms contributing to walking on uneven terrain is limited. We used a novel method for altering terrain unevenness on a treadmill to investigate the association between terrain unevenness and cortical activity in the prefrontal cortex, a region known to be involved in various cognitive functions. Methods: Prefrontal cortical activity was measured with functional near infrared spectroscopy while participants walked on a novel custom-made terrain treadmill surface across four different terrains: flat, low, medium, and high levels of unevenness. The assessments were conducted in younger adults, older adults with better mobility function and older adults with worse mobility function. Mobility function was assessed using the Short Physical Performance Battery. The primary hypothesis was that increasing the unevenness of the terrain would result in greater prefrontal cortical activation in all groups. Secondary hypotheses were that heightened prefrontal cortical activation would be observed in the older groups relative to the younger group, and that prefrontal cortical activation would plateau at higher levels of terrain unevenness for the older adults with worse mobility function, as predicted by the Compensation Related Utilization of Neural Circuits Hypothesis. Results: The results revealed a significant main effect of terrain, indicating a significant increase in prefrontal cortical activation with increasing terrain unevenness during walking in all groups. A significant main effect of group revealed that prefrontal cortical activation was higher in older adults with better mobility function compared to younger adults and older adults with worse mobility function in all pooled terrains, but there was no significant difference in prefrontal cortical activation between older adults with worse mobility function and younger adults. Contrary to our hypothesis, the older group with better mobility function displayed a sustained increase in activation but the other groups did not, suggestive of neural compensation. Additional findings were that task-related increases in prefrontal cortical activation during walking were lateralized to the right hemisphere in older adults with better mobility function but were bilateral in older adults with worse mobility function and younger adults. Discussion: These findings support that compared to walking on a flat surface, walking on uneven terrain surfaces increases demand on cognitive control resources as measured by prefrontal cortical activation.

Electrical Brain Activity during Human Walking with Parametric Variations in Terrain Unevenness and Walking Speed.

Mobile brain imaging with high-density electroencephalography (EEG) can provide insight into the cortical processes involved in complex human walking tasks. While uneven terrain is common in the natural environment and poses challenges to human balance control, there is limited understanding of the supraspinal processes involved with traversing uneven terrain. The primary objective of this study was to quantify electrocortical activity related to parametric variations in terrain unevenness for neurotypical young adults. We used high-density EEG to measure brain activity when thirty-two young adults walked on a novel custom-made uneven terrain treadmill surface with four levels of difficulty at a walking speed tailored to each participant. We identified multiple brain regions associated with uneven terrain walking. Alpha (8 - 13 Hz) and beta (13 - 30 Hz) spectral power decreased in the sensorimotor and posterior parietal areas with increasing terrain unevenness while theta (4 - 8 Hz) power increased in the mid/posterior cingulate area with terrain unevenness. We also found that within stride spectral power fluctuations increased with terrain unevenness. Our secondary goal was to investigate the effect of parametric changes in walking speed (0.25 m/s, 0.5m/s, 0.75 m/s, 1.0 m/s) to differentiate the effects of walking speed from uneven terrain. Our results revealed that electrocortical activities only changed substantially with speed within the sensorimotor area but not in other brain areas. Together, these results indicate there are distinct cortical processes contributing to the control of walking over uneven terrain versus modulation of walking speed on smooth, flat terrain. Our findings increase our understanding of cortical involvement in an ecologically valid walking task and could serve as a benchmark for identifying deficits in cortical dynamics that occur in people with mobility deficits.

Comparison of EEG Source Localization Using Simplified and Anatomically Accurate Head Models in Younger and Older Adults.

Accuracy of electroencephalography (EEG) source localization relies on the volume conduction head model. A previous analysis of young adults has shown that simplified head models have larger source localization errors when compared with head models based on magnetic resonance images (MRIs). As obtaining individual MRIs may not always be feasible, researchers often use generic head models based on template MRIs. It is unclear how much error would be introduced using template MRI head models in older adults that likely have differences in brain structure compared to young adults. The primary goal of this study was to determine the error caused by using simplified head models without individual-specific MRIs in both younger and older adults. We collected high-density EEG during uneven terrain walking and motor imagery for 15 younger (22±3 years) and 21 older adults (74±5 years) and obtained [Formula: see text]-weighted MRI for each individual. We performed equivalent dipole fitting after independent component analysis to obtain brain source locations using four forward modeling pipelines with increasing complexity. These pipelines included: 1) a generic head model with template electrode positions or 2) digitized electrode positions, 3) individual-specific head models with digitized electrode positions using simplified tissue segmentation, or 4) anatomically accurate segmentation. We found that when compared to the anatomically accurate individual-specific head models, performing dipole fitting with generic head models led to similar source localization discrepancies (up to 2 cm) for younger and older adults. Co-registering digitized electrode locations to the generic head models reduced source localization discrepancies by  âˆ¼  6 mm. Additionally, we found that source depths generally increased with skull conductivity for the representative young adult but not as much for the older adult. Our results can help inform a more accurate interpretation of brain areas in EEG studies when individual MRIs are unavailable.

Familial Risk of Graves Disease Among First-Degree Relatives and Interaction With Smoking: A Population-Based Study.

CONTEXT: Population-based studies on the familial aggregation of Graves disease (GD) are scarce and gene-environment interactions are not well-studied. OBJECTIVE: We evaluated the familial aggregation of GD and assessed interactions between family history and smoking. METHODS: Using the National Health Insurance database, which includes information on familial relationships and lifestyle risk factors, we identified 5 524 403 individuals with first-degree relatives (FDRs). Familial risk was calculated using hazard ratios (HRs), comparing the risk of individuals with and without affected FDRs. Interactions between smoking and family history were assessed on an additive scale using relative excess risk due to interaction (RERI). RESULTS: The HR among individuals with affected FDRs was 3.39 (95% CI, 3.30-3.48) compared with those without affected FDR, and among individuals with affected twin, brother, sister, father, and mother, the HRs were 36.53 (23.85-53.54), 5.26 (4.89-5.66), 4.12 (3.88-4.38), 3.34 (3.16-3.54), and 2.63 (2.53-2.74), respectively. Individuals with both a positive family history and smoking had an increased risk of disease (HR 4.68) with statistically significant interaction (RERI 0.94; 95% CI, 0.74-1.19). Heavy smokers with a positive family history showed a nearly 6-fold increased risk, which was higher than moderate smoking, suggesting a dose-response interaction pattern. Current smoking also showed a statistically significant interaction with family history (RERI 0.52; 95% CI, 0.22-0.82), while this was not observed for former smoking. CONCLUSION: A gene-environment interaction can be suggested between smoking and GD-associated genetic factors, which diminishes after smoking cessation. Smokers with a positive family history should be considered a high-risk group and smoking cessation should be advised.

Uneven terrain treadmill walking in younger and older adults.

We developed a method for altering terrain unevenness on a treadmill to study gait kinematics. Terrain consisted of rigid polyurethane disks (12.7 cm diameter, 1.3-3.8 cm tall) which attached to the treadmill belt using hook-and-loop fasteners. Here, we tested four terrain unevenness conditions: Flat, Low, Medium, and High. The main objective was to test the hypothesis that increasing the unevenness of the terrain would result in greater gait kinematic variability. Seventeen younger adults (age 20-40 years), 25 higher-functioning older adults (age 65+ years), and 29 lower-functioning older adults (age 65+ years, Short Physical Performance Battery score < 10) participated. We customized the treadmill speed to each participant's walking ability, keeping the speed constant across all four terrain conditions. Participants completed two 3-minute walking trials per condition. Using an inertial measurement unit placed over the sacrum and pressure sensors in the shoes, we calculated the stride-to-stride variability in step duration and sacral excursion (coefficient of variation; standard deviation expressed as percentage of the mean). Participants also self-reported their perceived stability for each condition. Terrain was a significant predictor of step duration variability, which roughly doubled from Flat to High terrain for all participant groups: younger adults (Flat 4.0%, High 8.2%), higher-functioning older adults (Flat 5.0%, High 8.9%), lower-functioning older adults (Flat 7.0%, High 14.1%). Similarly, all groups exhibited significant increases in sacral excursion variability for the Medium and High uneven terrain conditions, compared to Flat. Participants were also significantly more likely to report feeling less stable walking over all three uneven terrain conditions compared to Flat. These findings support the hypothesis that altering terrain unevenness on a treadmill will increase gait kinematic variability and reduce perceived stability in younger and older adults.

Active video games in fully immersive virtual reality elicit moderate-to-vigorous physical activity and improve cognitive performance in sedentary college students.

BACKGROUND: Active video games are a new method for increasing physical activity (PA). Fully immersive virtual reality (VR) is a hardware device on which an active video game can run. Active (video games in) VR (AVR), might increase immersion, game engagement, and moderate-to-vigorous PA (MVPA), thereby yielding greater exercise-related benefits, e.g., cognitive performance. METHODS: We examined the induction of MVPA via an AVR and a sedentary VR (SVR) as well as the effects of VR play on cognitive performance, which was monitored using 2 different methods. Each of 29 sedentary college students attended three 20-min laboratory sessions (AVR, SVR, or control) in a randomized order; during the control session, they sat quietly doing nothing. A fully immersive headset was used for the 2 video game sessions. We monitored and computed participants' PA using hip-worn accelerometers (wGT3x-bt; ActiGraph, Pensacola, FL, USA) and a heart rate band (Polar H7; Polar, Kempele, Finland). After each session, the participants completed a mnemonic similarity test (MST) to measure recognition memory. They also filled out a motion sickness questionnaire and an abbreviated game experience questionnaire. RESULTS: The AVR session induced a significantly greater heart rate and more time spent in MVPA than did either of the other 2 sessions regardless of the PA monitoring method. AVR elicited greater game experience questionnaire-assessed sensory and imaginative immersion, challenge, and positive affect than did SVR. The mnemonic similarity test recognition score was marginally higher post-AVR session than it was post-SVR session. CONCLUSION: AVR elicited MVPA without a significant increase in motion sickness and induced a better game experience and better borderline cognitive performance than did SVR.

Surveillance of patients with cirrhosis remains suboptimal in the United States.

BACKGROUND & AIMS: Regular monitoring/surveillance for liver complications is crucial to reduce morbidity and mortality in patients with cirrhosis. Recommendations from professional societies are available but adherence is not well studied, especially outside of academic centers. We aimed to determine the frequencies and factors associated with laboratory monitoring, and hepatocellular carcinoma (HCC) and esophageal varices (EV) surveillance in patients with cirrhosis. METHODS: We identified 82,427 patients with cirrhosis (43,280 compensated and 39,147 decompensated) from the Truven Health MarketScan Research Database®, 2007-2016. We calculated the proportion of patients with cirrhosis with various frequencies of procedures/testing: laboratory (complete blood count, comprehensive metabolic panel, and prothrombin time), HCC and EV surveillance. We also used multivariable logistic regression to determine factors associated with having procedures. RESULTS: The proportions of patients undergoing HCC surveillance (8.78%), laboratory testing (29.72%) at least every 6-12 months, or EV surveillance (10.6%) at least every 1-2 years were suboptimal. The majority did not have HCC (45.4%) or EV (80.3%) surveillance during the entire study period. On multivariable regression, age 41-55 (vs. <41) years, preferred provider organization (vs. health maintenance organization) insurance plan, specialist care (vs. primary care and other specialties), diagnosis between 2013-2016 (vs. 2007-2009), decompensated (vs. compensated) cirrhosis, non-alcoholic fatty liver disease (vs. viral hepatitis), and higher Charlson comorbidity index were associated with significantly higher odds of undergoing procedures/testing every 6-12 months and EV surveillance every 1-2 years. CONCLUSIONS: Despite modest improvements in more recent years, routine monitoring and surveillance for patients with cirrhosis is suboptimal. Further efforts including provider awareness, patient education, and system/incentive-based quality improvement measures are urgently needed. LAY SUMMARY: Patients with cirrhosis should undergo health monitoring for liver complications to achieve early detection and treatment. In a large nationwide cohort of 82,427 patients with cirrhosis in the United States, we found a low rate of adherence (well less than half) to routine blood test monitoring and surveillance for liver cancer and esophageal varices (swollen blood vessels in the abdomen that could lead to fatal bleeding). Adherence has increased in the recent years, but much more improvement is needed.

Rapid component of excess post-exercise oxygen consumption of children of different weight status after playing active video games.

BACKGROUND: Excess post-exercise oxygen consumption (EPOC) of children could indicate the potential of an exercise therapy to treat or prevent obesity. However, EPOC as a result of playing active video games (AVG) has been poorly investigated. Therefore, we aimed to investigate the rapid component of EPOC of children with healthy weight and overweight/obesity (according to their BMI percentile) after playing AVGs that feature predominately upper body (UB) and whole-body (WB) movement. METHODS: Twenty-one children with healthy weight (BMI percentile < 85%) and with overweight/obesity (BMI percentile ≥ 85%) randomly underwent two 10-min AVG sessions (UB and WB). The heart rate (HR), minute ventilation (VE), oxygen consumption (VO2) and carbon dioxide production (VCO2) were recorded during exercise and post-exercise recovery period. For the rapid component of EPOC in each AVG session, measurements were recorded every 15 s for 5-min of post-exercise recovery. The rate of perceived exertion (RPE) was also measured immediately before and after each AVG play. RESULTS: Children with overweight/obesity had a higher average of absolute VE, VO2, and VCO2 than their healthy-weight counterparts (BMI percentile < 85%; n = 21) during post-exercise recovery. RPE, HR, and HR% were not different between the game sessions and weight groups. Children with overweight/obesity showed a higher absolute VO2 during EPOC than healthy-weight children in both game sessions, but relative VO2 was higher in healthy-weight children during EPOC. No differences were observed for EPOC between UB and WB sessions. CONCLUSIONS: Children with overweight/obesity had a greater EPOC than healthy-weight children after AVG sessions in terms of absolute oxygen values, whereas healthy-weight children have higher EPOC considering relative VO2 when controlling for body mass. UB and WB AVGs induced a similar EPOC among children with healthy weight and overweight/obesity. As UB and WB AVGs induce the rapid component of EPOC in children regardless their weight status, AVGs could be used as an exercise method to treat and prevent child obesity.

Comparison of Inhibitory Control After Acute Bouts of Exergaming Between Children with Obesity and Their Normal-Weight Peers.

Objective: The benefits of exergaming on executive function in children have been increasingly reported; however, weight-dependent effects of exergames on executive function, and inhibitory control in particular, remain poorly understood. We examined performance on an inhibitory control task at baseline and following acute bouts of exergaming in children who varied in weight status. Materials and Methods: Forty 8-12-year-old children with obesity (n = 20) and normal weight (n = 20) performed neutral, congruent, and incongruent conditions of a Victoria Stroop Test (VST) before and after exergames through an Xbox One in an elementary classroom. We measured time spent in moderate-to vigorous-intensity activity through ActiGraph accelerometers and recorded gameplay time. Results: At baseline, children with obesity relative to their normal-weight peers had significantly longer reaction times (P = 0.011), resulting in significantly longer completion time (P = 0.005) during incongruent trials requiring greater inhibitory control, and therefore had higher interference scores (P = 0.024). However, following acute bouts of exergames, children with obesity compared with their normal-weight counterparts significantly decreased completion time (P = 0.013), made fewer errors (P = 0.012) during incongruent trials, and subsequently had reduced interference effects (P = 0.037). Children with obesity and normal-weight children spent similar time (minutes) (7.8 vs. 8.6, P = 0.725) in moderate-to vigorous-intensity activity during similar gameplay time (8.7 vs. 10.5, P = 0.819). Conclusion: Our results suggest that greater, acute cognitive gains occur in children with obesity relative to normal-weight children following similar intensity and duration of exergames, which may be due to reduced inhibitory control capacity at baseline in childhood obesity.

The impact of narratives and active video games on long-term moderate-to-vigorous physical activity: A randomized controlled trial protocol.

BACKGROUND: Although physical activity (PA) has been shown in helping prevent and treat obesity, current PA interventions are still not effective in ameliorating the obesity epidemic. Additional forms of PA need to be investigated to improve PA engagement and outcomes. We hypothesize that pairing a narrative (i.e., story) with an active video game (AVG), a less traditional form of PA, will increase participant engagement in PA. This paper presents the rationale, implementation, and pilot results of a study assessing the effect of narrative's impact on PA and a series of other health outcomes. OBJECTIVE: This paper presents the rationale, implementation, and pilot results of a study assessing the effect of narrative's impact on PA and a series of other health outcomes. METHODS/DESIGN: The Active Video Game Study is a six-month randomized controlled single-blind trial projected to include 210 participants. The intervention strategy will pair a narrative to an active video game (AVG). Participants will be randomized into 3 groups: condition A [Narrative + AVG], condition B [AVG Only], and condition C [Control]. Participants will undergo three in-person data collection visits over the course of six months. Inclusion criteria are that children are between the ages of 8-12 and have a BMI ≥ 85%. The primary outcome is change in moderate to vigorous physical activity (MVPA). Secondary outcome measures include change in BMI percentile, fasting insulin and glucose, lipid panel, C-reactive protein, and cognitive function. A pilot trial of n = 6 was conducted to help develop procedures and address problems that could arise in the main trial. DISCUSSION: Successful completion of this study will provide the empirical basis for novel intervention and design strategies to enhance the impact of AVGs on long-term MVPA.

Correction: The Effect of Narrative on Physical Activity via Immersion During Active Video Game Play in Children: Mediation Analysis.

[This corrects the article DOI: 10.2196/17994.].

The Effect of Narrative on Physical Activity via Immersion During Active Video Game Play in Children: Mediation Analysis.

BACKGROUND: Active video games (AVGs) can increase physical activity (PA) and help produce higher physiological expenditure. Animated narrative videos (NVs) possess unique immersive and motivational properties. When added to AVGs, they have been found to increase moderate-to-vigorous physical activity (MVPA) as opposed to the original no video condition. However, there is no evidence of whether that was due to the NV or the addition of an animated video to an AVG. OBJECTIVE: This study aimed to investigate the differential effect of adding an NV versus a nonnarrative video (NNV) to an AVG on PA parameters and physiological responses and to explore the mediating role of immersion. METHODS: A total of 22 children aged 8 to 12 years were randomly assigned to the NV or NNV condition. They were instructed to play an AVG (on Xbox Kinect) for as long as they wanted. We used accelerometers to estimate the time spent (in minutes) in MVPA. Heart rate (HR) and rate of perceived exertion (RPE) were measured before, during, and after the AVG play session. The participants then reported their experience of narrative immersion via a questionnaire. RESULTS: The NV group had significantly higher narrative immersion (mean 3.50, SD 0.55 vs mean 2.91, SD 0.59; P=.03) and MVPA (mean 19.46, SD 13.31 vs mean 7.85, SD 5.83; P=.02) than the NNV group. Narrative immersion was positively correlated with MVPA (r=0.52; P=.01) and average HR during AVG (r=0.43; P=.05). Mediation analysis indicated that narrative immersion mediated the effect of NV (NV vs NNV) on MVPA (direct effect: beta=7.51; P=.01). The indirect effect was that NV was positively correlated with the mediator variable narrative immersion (beta=.59; P=.03), which was itself marginally associated with MVPA (beta=6.95; P=.09); when narrative immersion was included in the model, the regression coefficient was attenuated. CONCLUSIONS: AVG with added narratives elicits more narrative immersion, resulting in more minutes in MVPA. Narrative immersion served as a mediator between NV and MVPA via its elicitation of an elevated HR without increasing RPE. The inclusion of immersive narratives in AVG could be helpful for inducing MVPA, to enhance AVG engagement without additional exertion.

Exploring Energy Expenditure and Body Movement of Exergaming in Children of Different Weight Status.

PURPOSE: This study examined differences in energy expenditure and bodily movement among children of different weight status during exergames that varied in mode and intensity. METHODS: Fifty-seven 8- to 12-year-old children including overweight/obesity (n = 28) and normal weight (n = 29) played three 10-minute interval Xbox One exergames (Fruit Ninja, Kung-Fu, and Shape Up) categorized based on predominantly upper-, whole-, or lower-limb movement, respectively. The authors measured bodily movement through accelerometry and obtained energy expenditure and metabolic equivalent (MET) via indirect calorimetry. RESULTS: Energy expended during gameplay was the highest in Shape Up (P < .01) and higher in Kung-Fu than Fruit Ninja (P < .01). Absolute energy expenditure was significantly higher in overweight/obese children (P < .01), but not when controlling for body mass across 3 exergames (P > .05). Based on the MET cut-points, overweight/obese children spent more time at light intensity (<3 METs) for Fruit Ninja (P < .05) and Shape Up (P < .01), but less time at vigorous intensity (≥6 METs) for Kung-Fu (P < .01) and Shape Up (P < .01). Lower-limb movements during Shape Up were less in overweight/obese children (P = .03). CONCLUSION: Although children in both groups expended similar energy relative to their body mass during gameplay, overweight/obese children spent more time at light intensity but less time at vigorous intensity with fewer movements especially while playing a lower limb-controlled exergame.

Application and Validation of Activity Monitors' Epoch Lengths and Placement Sites for Physical Activity Assessment in Exergaming.

We assessed the agreement of two ActiGraph activity monitors (wGT3X vs. GT9X) placed at the hip and the wrist and determined an appropriate epoch length for physical activity levels in an exergaming setting. Forty-seven young adults played a 30-min exergame while wearing wGT3X and GT9X on both hip and wrist placement sites and a heart rate sensor below the chest. Intraclass correlation coefficient indicated that intermonitor agreement in steps and activity counts was excellent on the hip and good on the wrist. Bland-Altman plots indicated good intermonitor agreement in the steps and activity counts on both placement sites but a significant intermonitor difference was detected in steps on the wrist. Time spent in sedentary and physical activity intensity levels varied across six epoch lengths and depended on the placement sites, whereas time spent from a 1-s epoch of the hip-worn monitors most accurately matched the relative exercise intensity by heart rate. Hip placement site was associated with better step-counting accuracy for both activity monitors and more valid estimation of physical activity levels. A 1-s epoch was the most appropriate epoch length to detect short bursts of intense physical activity and may be the best choice for data processing and analysis in exergaming studies examining intermittent physical activities.

Narrative and active video game in separate and additive effects of physical activity and cognitive function among young adults.

Physically active video games (AVGs) have been found to positively impact physical activity behaviors, especially when a narrative is added. However, the motivational and cognitive benefits of adding narrative to AVG are unclear. We examined the separate and additive effects of narrative and AVG on physical activity and cognitive function versus an active comparator, such as a sedentary video game (SVG). We randomly assigned young adults to one of four groups (narrative-AVG, AVG, narrative-SVG, or SVG) and had them complete sustained attention and working memory tasks before and after a 30-min experimental condition. Participants in both narrative-AVG and AVG groups achieved a moderate-intensity physical activity, while adding narrative to AVG resulted in higher step counts and more time spent in moderate-to-vigorous physical activity than AVG without narrative. Regardless of the narrative effect, participants in both AVG groups performed better on overall working memory than both SVG groups, while both AVG and SVG groups similarly achieved maximal performance in sustained attention. Working memory enhancement was positively correlated with increased heart rate. Participants in narrative-SVG group had a better response accuracy in working memory than those who played SVG without narrative. Taken together, adding narrative to AVG as a motivational component increased physical activity, which was the primary factor in the improvement of overall working memory.

Association between aerobic fitness and cerebrovascular function with neurocognitive functions in healthy, young adults.

Studies of the effects of physical activity on cognition suggest that aerobic fitness can improve cognitive abilities. However, the physiological mechanisms for the cognitive benefit of aerobic fitness are less well understood. We examined the association between aerobic fitness and cerebrovascular function with neurocognitive functions in healthy, young adults. Participants aged 18-29 years underwent measurements of cerebral vasomotor reactivity (CVMR) in response to rebreathing-induced hypercapnia, maximal oxygen uptake (VO2max) during cycle ergometry to voluntary exhaustion, and simple- and complex-neurocognitive assessments at rest. Ten subjects were identified as having low-aerobic fitness (LF < 15th fitness percentile), and twelve subjects were identified as having high-aerobic fitness (HF > 80th fitness percentile). There were no LF versus HF group differences in cerebrovascular hemodynamics during the baseline condition. Changes in middle cerebral artery blood velocity and CVMR during hypercapnia were elevated more in the HF than the LF group. Compared to the LF, the HF performed better on a complex-cognitive task assessing fluid reasoning, but not on simple attentional abilities. Statistical modeling showed that measures of VO2max, CVMR, and fluid reasoning were positively inter-correlated. The relationship between VO2max and fluid reasoning, however, did not appear to be reliably mediated by CVMR. In conclusion, a high capacity for maximal oxygen uptake among healthy, young adults was associated with greater CVMR and better fluid reasoning, implying that high-aerobic fitness may promote cerebrovascular and cognitive functioning abilities.

The positive cognitive impact of aerobic fitness is associated with peripheral inflammatory and brain-derived neurotrophic biomarkers in young adults.

There is ample evidence for supporting the positive impact of aerobic fitness on cognitive function, but little is known about the physiological mechanisms. The objective of this study was to investigate whether the positive cognitive impact of aerobic fitness is associated with inflammatory and neurotrophic peripheral biomarkers in young adults aged 18 to 29years (n=87). For the objective assessment of aerobic fitness, we measured maximal oxygen uptake (VO2max) as a parametric measure of cardiorespiratory capacity. We demonstrated that young adults with the higher levels of VO2max performed better on computerized cognitive tasks assessing sustained attention and working memory. This positive VO2max-cognitive performance association existed independently of confounders (e.g., years of education, intelligence scores) but was significantly dependent on resting peripheral blood levels of inflammatory (C-reactive protein, CRP) and neurotrophic (brain-derived neurotrophic factor, BDNF) biomarkers. Statistical models showed that CRP was a mediator of the effect of VO2max on working memory. Further, BDNF was a moderator of the effect of VO2max on working memory. These mediating and moderating effects occurred in individuals with higher levels of aerobic fitness. The results suggest that higher aerobic fitness, as measured by VO2max, is associated with enhanced cognitive functioning and favorable resting peripheral levels of inflammatory and brain-derived neurotrophic biomarkers in young adults.

Acute high-intensity exercise-induced cognitive enhancement and brain-derived neurotrophic factor in young, healthy adults.

Acute exercise can positively impact cognition. The present study examined the effect of acute high-intensity aerobic exercise on prefrontal-dependent cognitive performance and brain-derived neurotrophic factor (BDNF). Fifty-eight young adults were randomly assigned to one of two experimental groups: (a) an acute bout of high-intensity exercise (n=29) or (b) a non-exercise control (n=29). Participants in the exercise group improved performance on inhibitory control in Stroop interference and on cognitive flexibility in Trail Making Test (TMT) Part-B compared with participants in the control group and increased BDNF immediately after exercise. There was a significant relationship between BDNF and TMT Part-B on the pre-post change following exercise. These findings provide support for the association between improved prefrontal-dependent cognitive performance and increased BDNF in response to acute exercise. We conclude that the changes in BDNF concentration may be partially responsible for prefrontal-dependent cognitive functioning following an acute bout of exercise.

Cognitive enhancement by transcranial laser stimulation and acute aerobic exercise.

This is the first randomized, controlled study comparing the cognitive effects of transcranial laser stimulation and acute aerobic exercise on the same cognitive tasks. We examined whether transcranial infrared laser stimulation of the prefrontal cortex, acute high-intensity aerobic exercise, or the combination may enhance performance in sustained attention and working memory tasks. Sixty healthy young adults were randomly assigned to one of the following four treatments: (1) low-level laser therapy (LLLT) with infrared laser to two forehead sites while seated (total 8 min, 1064 nm continuous wave, 250 mW/cm(2), 60 J/cm(2) per site of 13.6 cm(2)); (2) acute exercise (EX) of high-intensity (total 20 min, with 10-min treadmill running at 85-90 % VO2max); (3) combined treatment (LLLT + EX); or (4) sham control (CON). Participants were tested for prefrontal measures of sustained attention with the psychomotor vigilance task (PVT) and working memory with the delayed match-to-sample task (DMS) before and after the treatments. As compared to CON, both LLLT and EX reduced reaction time in the PVT [F(1.56) = 4.134, p = 0.01, η (2) = 0.181] and increased the number of correct responses in the DMS [F(1.56) = 4.690, p = 0.005, η (2) = 0.201], demonstrating a significant enhancing effect of LLLT and EX on cognitive performance. LLLT + EX effects were similar but showed no significantly greater improvement on PVT and DMS than LLLT or EX alone. The transcranial infrared laser stimulation and acute aerobic exercise treatments were similarly effective for cognitive enhancement, suggesting that they augment prefrontal cognitive functions similarly.

The effect of an amino acid beverage on glucose response and glycogen replenishment after strenuous exercise.

PURPOSE: We previously reported that an amino acid mixture (AA) was able to lower the glucose response to an oral glucose challenge in both rats and humans. Increased glucose uptake and glycogen storage in muscle might be associated with the faster blood glucose clearance. We therefore tested the effect of two different doses of AA provided with a carbohydrate supplement on blood glucose homeostasis and muscle glycogen replenishment in human subjects after strenuous aerobic exercise. METHODS: Ten subjects received a carbohydrate (1.2 g/kg body weight, CHO), CHO/HAA (CHO + 13 g AA), or CHO/LAA (CHO + 6.5 g AA) supplement immediately and 2 h after an intense cycling bout. Muscle biopsies were performed immediately and 4 h after exercise. RESULTS: The glucose responses for CHO/HAA and CHO/LAA during recovery were significantly lower than CHO, as was the glucose area under the curve (CHO/HAA 1259.9 ± 27.7, CHO/LAA 1251.5 ± 47.7, CHO 1376.8 ± 52.9 mmol/L 4 h, p < 0.05). Glycogen storage rate was significantly lower in CHO/HAA compared with CHO, while it did not differ significantly between CHO/LAA or CHO (CHO/HAA 15.4 ± 2.0, CHO/LAA 18.1 ± 2.0, CHO 21.5 ± 1.4 µmol/g wet muscle 4 h). CHO/HAA caused a significantly higher insulin response and a greater effect on mTOR and Akt/PKB phosphorylation compared with CHO. Phosphorylation of AS160 and glycogen synthase did not differ across treatments. Likewise, there were no differences in blood lactate across treatments. CONCLUSIONS: The AA lowered the glucose response to a carbohydrate supplement after strenuous exercise. However, it was not effective in facilitating subsequent muscle glycogen storage.