Effects of incremental exercise on cerebral oxygenation measured by near-infrared spectroscopy: A systematic review

Blunted cerebral hemodynamic responses to incremental exercise in patients with end-stage renal disease

PURPOSE

The aims of this study were to compare cerebral hemodynamics and maximal oxygen uptake (VO2peak) in patients with end-stage renal disease (ESRD) vs. age-matched healthy controls during maximal exercise.

METHODS

Twelve patients with ESRD and twelve healthy adults (CTR group) performed exhaustive incremental exercise test. Throughout the exercise test, near-infrared spectroscopy allowed the investigation of changes in oxyhemoglobin (∆O2Hb), deoxyhemoglobin (∆HHb), and total hemoglobin (∆THb) in the prefrontal cortex.

RESULTS

Compared to CTR, VO2peak was significantly lower in ESRD group (P < 0.05). Increase in ∆THb (i.e., cerebral blood volume) was significantly blunted in ESRD (P < 0.05). ESRD patients also had impaired changes in cerebral ∆HHb and ∆O2Hb during high intensity of exercise (P < 0.05). Finally, no significant correlation was observed between VO2peak and changes in cerebral hemodynamics parameters in both groups (All P > 0.05).

CONCLUSION

Maximal exercise highlights subtle disorders of both hemodynamics and neuronal oxygenation in the prefrontal cortex in patients with ESRD. This may contribute to both impaired cognitive function and reduced exercise tolerance throughout the progression of the disease.

Inverted U-shape-like functional connectivity alterations in cognitive resting-state networks depending on exercise intensity: An fMRI study

Acute physical activity influences cognitive performance. However, the relationship between exercise intensity, neural network activity, and cognitive performance remains poorly understood. This study examined the effects of different exercise intensities on resting-state functional connectivity (rsFC) and cognitive performance. Twenty male athletes (27.3 ± 3.6 years) underwent cycling exercises of different intensities (high, low, rest/control) on different days in randomized order. Before and after, subjects performed resting-state functional magnetic resonance imaging and a behavioral Attention Network Test (ANT). Independent component analysis and Linear mixed effects models examined rsFC changes within ten resting-state networks. No significant changes were identified in ANT performance. Resting-state analyses revealed a significant interaction in the Left Frontoparietal Network, driven by a non-significant rsFC increase after low-intensity and a significant rsFC decrease after high-intensity exercise, suggestive of an inverted U-shape relationship between exercise intensity and rsFC. Similar but trend-level rsFC interactions were observed in the Dorsal Attention Network (DAN) and the Cerebellar Basal Ganglia Network. Explorative correlation analysis revealed a significant positive association between rsFC increases in the right superior parietal lobule (part of DAN) and better ANT orienting in the low-intensity condition. Results indicate exercise intensity-dependent subacute rsFC changes in cognition-related networks, but their cognitive-behavioral relevance needs further investigation.

Aerobic exercise promotes emotion regulation: a narrative review

Aerobic exercise improves the three stages of emotion regulation: perception, valuation and action. It reduces the perception of negative emotions, encourages individuals to reinterpret emotional situations in a positive or non-emotional manner, and enhances control over emotion expression behaviours. These effects are generated via increased prefrontal cortex activation, the strengthening of functional connections between the amygdala and several other brain regions, and the enhancement of the plasticity of key emotion regulation pathways and nodes, such as the uncinate fasciculus. The effect of aerobic exercise on emotion regulation is influenced by the exercise intensity and duration, and by individuals' exercise experience. Future research may explore the key neural basis of aerobic exercise's promotion of emotion regulation.

Muscle oxygen supply impairment during maximal exercise in patients undergoing dialysis therapy

This study aimed to investigate whether Chronic Kidney Disease (CKD) influences O2 supply including O2 delivery and release to the active muscles during maximal physical exercise. Twelve CKD patients undergoing dialysis therapy (HD group) and twelve healthy adults (CTR group) performed an incremental exercise test to determine maximal oxygen uptake (VO2peak). Throughout the exercise, near-infrared spectroscopy allowed the investigation of changes in oxyhemoglobin (∆O2Hb), deoxyhemoglobin (∆HHb), and total hemoglobin (∆THb) in the vastus lateralis muscle. VO2peak was significantly lower in HD group. In addition, HD patients had impaired changes in muscular oxygenation (∆HHb and ∆O2Hb) and blood volume (∆THb) during the exercise (p < 0.05). Moreover, a positive correlation was observed between VO2peak and muscle blood volume (∆THb) in both groups (p < 0.05). This study provides the first evidence that HD patients displayed lower VO2peak and blunted muscular deoxyhemoglobin increase during exercise. This result supports the hypothesis of an increase in oxygen affinity and/or mitochondrial dysfunction in this population.

Exercise Reshapes the Brain: Molecular, Cellular, and Structural Changes Associated with Cognitive Improvements

Physical exercise is well known as a non-pharmacological and holistic therapy believed to prevent and mitigate numerous neurological conditions and alleviate ageing-related cognitive decline. To do so, exercise affects the central nervous system (CNS) at different levels. It changes brain physiology and structure, promoting cognitive improvements, which ultimately improves quality of life. Most of these effects are mediated by neurotrophins release, enhanced adult hippocampal neurogenesis, attenuation of neuroinflammation, modulation of cerebral blood flow, and structural reorganisation, besides to promote social interaction with beneficial cognitive outcomes. In this review, we discuss, based on experimental and human research, how exercise impacts the brain structure and function and how these changes contribute to cognitive improvements. Understanding the mechanisms by which exercise affects the brain is essential to understand the brain plasticity following exercise, guiding therapeutic approaches to improve the quality of life, especially in obesity, ageing, neurodegenerative disorders, and following traumatic brain injury.

Infrared Spectroscopy: A New Frontier in Hematological Disease Diagnosis

Hematological diseases, due to their complex nature and diverse manifestations, pose significant diagnostic challenges in healthcare. The pressing need for early and accurate diagnosis has driven the exploration of novel diagnostic techniques. Infrared (IR) spectroscopy, renowned for its noninvasive, rapid, and cost-effective characteristics, has emerged as a promising adjunct in hematological diagnostics. This review delves into the transformative role of IR spectroscopy and highlights its applications in detecting and diagnosing various blood-related ailments. We discuss groundbreaking research findings and real-world applications while providing a balanced view of the potential and limitations of the technique. By integrating advanced technology with clinical needs, we offer insights into how IR spectroscopy may herald a new era of hematological disease diagnosis.

Prefrontal NIRS signal is unaffected by forehead Doppler flux during incremental cycling exercise

Near-infrared spectroscopy (NIRS) is used to measure tissue concentrations of oxyhemoglobin (O2 Hb) and deoxyhemoglobin (HHb). In the context of exercise, NIRS confers a higher signal-to-noise ratio than other neuroimaging techniques. However, part of the signal may be influenced by thermoregulatory hyperemia in the superficial cutaneous capillaries of the forehead. The degree to which NIRS signals during exercise reflect cerebral or extracerebral hemodynamic changes is a continuing source of controversy. However, the influence of skin blood flow may be attenuated depending on the NIRS technique (e.g., frequency domain machines with maximal optode separation distances >3.5 cm). The purpose of this study was to compare the changes in forehead skin blood flow and cerebral hemoglobin concentration during incremental exercise versus direct vasodilation of the forehead skin induced by gradual local heating. Thirty participants (12 females, 18 males; age: 20.8 ± 3.2 years; body mass index: 23.8 ± 3.7 kg·m-2 ) participated in the study. Forehead skin blood flow was quantified laser Doppler flux and absolute concentrations of cerebral O2 Hb and HHb were measured by NIRS. Local heating significantly increased the Doppler flux signal across time and these changes were significantly correlated with skin temperature. During incremental exercise, skin temperature, Doppler flux, O2 Hb and HHb increased however, the only significant change that was consistently correlated with Doppler flux was skin temperature. Therefore, a significant change in forehead skin blood flow may not significantly the NIRS hemoglobin data, depending on the type of NIRS device used.

Differential effects of acute cardiovascular exercise on explicit and implicit motor memory: The moderating effects of fitness level

A single bout of cardiovascular exercise (CE) performed after practice can facilitate the consolidation of motor memory. However, the effect is variable and may be modulated by different factors such as the motor task's or participant's characteristics and level of awareness during encoding (implicit vs explicit learning). This study examines the effects of acute CE on the consolidation of motor sequences learned explicitly and implicitly, exploring the potential moderating effect of fitness level and awareness. Fifty-six healthy adults (24.1 ± 3.3 years, 32 female) were recruited. After practicing with either the implicit or explicit variant of the Serial Reaction Time Task (SRTT), participants either performed a bout of 16 min of vigorous CE or rested for the same amount of time. Consolidation was quantified as the change in SRTT performance from the end of practice to a 24 h retention test. Fitness level (V̇O2peak) was determined through a graded exercise test. Awareness (implicit vs explicit learning) was operationalized using a free recall test conducted immediately after retention. Our primary analysis indicated that CE had no statistically significant effects on consolidation, regardless of the SRTT's variant utilized during practice. However, an exploratory analysis, classifying participants based on the level of awareness gained during motor practice, showed that CE negatively influenced consolidation in unfit participants who explicitly acquired the motor sequence. Our findings indicate that fitness level and awareness in sequence acquisition can modulate the interaction between CE and motor memory consolidation. These factors should be taken into account when assessing the effects of CE on motor memory.

Aerobic physical exercise versus dual-task cognitive walking in cognitive rehabilitation of people with stroke: a randomized clinical trial

Introduction

Stroke is a neurological deficit caused by an acute focal injury to the central nervous system due to vascular injury that can result in loss of neurological function, lasting brain damage, long-term disability and, in some cases, death. The literature reports that aerobic physical exercise, as well as dual-task cognitive walking, are used for the cognitive recovery of people with stroke. We aimed to assess whether aerobic physical exercise influences post-stroke cognitive recovery, namely performance on selective and sustained attention. We tested the hypothesis that post-stroke aerobic physical exercise leads to more significant gains than post-stroke dual-task cognitive walking.

Methods

We used a Randomized Clinical Trial, single-blind, parallel group, to verify the existence of differences between two groups. A total of 34 patients with subacute to chronic stroke were divided into two groups to train three times a week for 12 weeks: the aerobic physical exercise (PE) group engaged in 20 min on a treadmill, 20 min on a stationary bicycle and 5 min on a desk bike pedal exerciser per session; the dual-task (DT) gait exercise group walked for 45 min while simultaneously performing cognitive tasks per session. All participants were assessed on cognitive functioning with the Mini-Mental State Examination (MMSE) and d2 Test of Attention before acute interventions and post interventions. We have also applied a Visual Analog Scale to monitor the participants' perceived difficulty, pre-, post-acute, and post-chronic interventions. Participants also responded to a Borg Scale of perceived exertion following the acute and the final session of chronic training.

Results

A mixed model ANOVA revealed a significant interaction effect with a large effect size for most of the cognitive variables under study. The variables associated with the d2 Test of Attention showed significant differences between the groups, mainly from T0 to T2. Also for MMSE, an ANOVA revealed a significant interaction effect with significant improvements from T0 to T2. Our results strongly suggest that aerobic physical exercise is more beneficial than dual-task cognitive-gait exercise since in the PE group, cognitive attention scores increase, and cognitive impairment and perception of exertion decrease, compared to the DT group.

Conclusion

These findings support that PE provides more significant benefits for patients post-stroke when compared to DT.

Changes in stress pathways as a possible mechanism of aerobic exercise training on brain health: a scoping review of existing studies

Physical activity (PA) in the form of aerobic exercise (AE) preserves and improves neurocognitive function across the lifespan. However, a mechanistic understanding of the pathways by which aerobic exercise impacts brain health is still lacking, particularly with respect to stress-related pathways. One mechanistic hypothesis is that AE improves neurocognitive health in part by modifying circulating levels of stress-related hormones and signaling factors associated with the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS), as commonly measured by the biomarkers cortisol (CORT) and salivary α-amylase (sAA). Thus, this hypothesis predicts that changes in stress biomarkers, such as CORT and sAA, are possible explanatory pathways mediating the positive effects of AE on neurocognitive health. In the present review article, we provide a summary of available studies examining the possibility that exercise-induced changes to stress biomarkers could partly account for exercise-related improvements in neurocognitive health. Our review indicates that despite the intuitive appeal of this hypothesis, there is insufficient evidence available to conclude that chronic and habitual AE affects neurocognitive health by altering stress biomarker pathways. The cross-sectional nature of the majority of reviewed studies highlights the need for well-controlled studies to adequately test this hypothesis.

Medium chain triglycerides with a C8:C10 ratio of 30:70 enhances cognitive performance and mitigates the cognitive decline associated with prolonged exercise in young and healthy adults

INTRODUCTION

Prolonged exercise has been linked to a decline in cognitive function due to a variety of factors, such as a drop in oxygen in the prefrontal cortex and an increase in stress hormones and neurotransmitters. Medium chain triglycerides (MCTs) may possibly offset this decline as they provide energy for the brain via both direct and indirect pathways, alongside promoting chronic physiological adaptations within the brain.

METHODS

Participants were divided into two groups; MCT (n = 9) and Placebo (n = 10). The MCT gels contained 6 g of MCT with a C8:C10 ratio of 30:70, whereas the placebo gels contained carbohydrates of similar calorific value to the MCT gels. Participants visited the laboratory on three occasions (familiarisation/fitness test, pre-supplementation, post-supplementation), during which they performed a battery of cognitive tasks assessing domains such as processing speed, working memory, selective attention, decision making and coordination, before and after a prolonged bout of exercise (60 mins at 90% gas exchange threshold (GET). A 2-week supplementation period between visits 2 and 3 involved the ingestion of 2 gels per day.

RESULTS

Exercise resulted in detriments in most cognitive tasks pre-supplementation for both groups, and post-supplementation for the Placebo group (main effect ps< 0.05). Post-supplementation, the effect of exercise was mediated in the MCT group for all cognitive tasks (main effect ps< 0.05), except for the Digit and Spatial Span Backwards test phases (main effect ps> 0.05). Furthermore, MCT supplementation enhanced before-exercise cognitive performance and in some measures, such as working memory, this was maintained after-exercise (interaction effect ps> 0.05).

CONCLUSIONS

Chronic MCT supplementation enhanced before-exercise cognitive performance and offset the cognitive decline caused by a prolonged bout of exercise. In some cases, improvements in before-exercise cognitive performance were maintained after-exercise.

Differences in the prefrontal cortex responses of healthy young men performing either water-based or land-based exercise at light to moderate intensity

Cerebral blood flow increases more during water-based exercise than land-based exercise owing to the effects of end-tidal CO₂ (PETCO₂) and mean arterial pressure (MAP) changes due to water immersion. However, it is unclear whether oxygenated hemoglobin (oxy-Hb) concentrations in the prefrontal cortex (PFC) are increased more by water-based or land-based exercise. We hypothesized that oxy-Hb concentrations in the PFC are higher during water-based exercise than land-based exercise when the exercise intensity is matched. To test this hypothesis, 10 healthy participants (age: 24.2 ± 1.7 years; height: 1.75 ± 0.04 m; weight: 69.5 ± 5.2 kg) performed light- to moderate-intensity cycling exercise in water (water-based cycling (WC); chest-high water at 30 °C) and on land (LC). Stroke volume, cardio output, heart rate, MAP, respiratory rate, PETCO₂, and oxy-Hb in the PFC were assessed during 15 min of exercise, with exercise intensity increased every 5 min. Both WC and LC significantly increased oxy-Hb concentrations in the PFC as exercise intensity was increased (intensity effect: p < 0.001). There was no significant difference in oxy-Hb concentrations during WC and LC in most prefrontal areas, although significant differences were found in areas corresponding to the left dorsolateral PFC (exercise effect: p < 0.001). Thus, WC and LC increase oxy-Hb concentrations in the PFC in a similar manner with increasing exercise intensity, but part of the PFC exhibits enhanced oxy-Hb levels during WC. The neural response of the PFC may differ during water-based and land-based exercise owing to differences in external information associated with water immersion.

Cerebral oxygenation during cardiopulmonary exercise testing in cardiorespiratory diseases: A systematic review

BACKGROUND

Cardiopulmonary exercise testing (CPET) is the gold standard for analyzing cardiorespiratory fitness and integrating physiological responses. However, the presence of chronic diseases may compromise cerebral hemodynamic responses during CPET. In addition, the acute response of cerebral oxygenation during incremental CPET may identify abnormal behavior and ensure greater safety for patients with cardiovascular, respiratory, and metabolic diseases.

OBJECTIVE

To summarize the cerebral oxygenation acute response during CPET of patients with cardiovascular, metabolic, or respiratory diseases.

METHODS

From inception to 23rd September 2022, five databases (PubMed, SCOPUS, Web of Science, Embase and CINAHAL) were searched for cross-sectional studies performing incremental CPET and measuring the cerebral oxygenation acute response in cardiovascular, metabolic, or respiratory diseases compared with healthy individuals. The Downs and Black tool assessed the risk of bias of the studies.

RESULTS

We included seven studies with 428 participants (305 men and 123 women), aged 43 to 70 years. Of these, 101 had heart failure NYHA II and III; 77 idiopathic dilated cardiomyopathy; 33 valvular disease; 25 coronary heart disease; 22 pulmonary arterial hypertension; 15 had severe obstructive sleep apnea (OSA) and 166 were apparently healthy. There was no eligible article with metabolic disease. There was a lower magnitude increase in cerebral oxygenation of cardiovascular patients compared with the healthy individuals during the CPET. Furthermore, pulmonary arterial hypertension patients presented increased cerebral oxygen extraction, differently to those with severe OSA.

CONCLUSION

Considering the heterogeneity of the included studies, patients with cardiovascular disease may suffer from reduced cerebral oxygen supply, and individuals with OSA presented lower brain oxygen extraction during the CPET. Future studies should aim for strategies to improve cerebral oxygenation to ensure greater safety at CPET of cardiovascular and OSA patients. An acute response pattern for metabolic and other respiratory diseases was not established.

Does Beetroot Supplementation Improve Performance in Combat Sports Athletes? A Systematic Review of Randomized Controlled Trials

While studies on dietary nitrate (NO₃^-) supplementation and its impact on combat sports performance are increasing, finite conclusions from currently available investigations remain unclear. Thus, the present systematic review examined the acute and chronic ergogenic effect(s) of dietary nitrate intake from beetroot on different aspects of combat sports performance. A systematic search for randomized placebo-controlled studies investigating the effects of beetroot supplementation on combat sports outcomes was performed through Scopus, PubMed/MEDLINE, Web of Science, Scielo, Sport Discus, and Cochrane Library databases up to 2 January 2023. The different terms related to beetroot and to combat sports were connected in the search strategies using the Boolean operators 'AND' and 'OR'. A total of nine studies with good methodological quality (based on the Cochrane risk of bias tool) fulfilled the inclusion criteria. Seven studies used an acute supplementation strategy, while the other two studies utilized chronic supplementation. Findings showed beetroot intake may be an effective tool to improve oxidative metabolism and muscle force production (i.e., isokinetic and isometric) in combat sports athletes. However, these effects may depend on the population, intake duration, muscle group activated, and exercise type. Future studies are required to (1) understand the effects on female athletes and (2) elucidate the impacts of dosing protocols and specific exercise modalities for enhancing combat sports performance.

Effects of acute endurance, strength, and coordination exercise interventions on attention in adolescents: A randomized controlled study

OBJECTIVES

The aim of this study was to compare three different modes of an acute bout of exercise - endurance, strength, and coordination - in their effects on adolescents' attention.

DESIGN

This was a preregistered, prospective, randomized intervention study with four groups and two distinct measurement occasions.

METHOD

Eighty adolescent students aged 15-18 years were randomized to one of three exercise intervention groups (endurance, strength, coordination) or to a non-exercise, control group. The exercise interventions lasted for 25 min. The random assignment to the study groups was stratified according to participants' age and gender. Before and after the exercise intervention, all participants completed the revised d2-test of attention. A 4 × 2 repeated measures ANOVA with contrast-coded test was used as the main analysis method.

RESULTS

Attentional test performance increased from before to after the exercise intervention for all exercise groups, as compared with the control group. The three exercise groups improved equally and did not differ in their attentional scores after the intervention.

CONCLUSIONS

An acute bout of exercise was in general beneficial for adolescent students' attention, while the mode of the provided exercise training was not decisive. School directors and teachers are encouraged to incorporate exercise-related breaks into their school plan.

Fatigue and Human Performance: An Updated Framework

Fatigue has been defined differently in the literature depending on the field of research. The inconsistent use of the term fatigue complicated scientific communication, thereby limiting progress towards a more in-depth understanding of the phenomenon. Therefore, Enoka and Duchateau (Med Sci Sports Exerc 48:2228-38, 2016, [3]) proposed a fatigue framework that distinguishes between trait fatigue (i.e., fatigue experienced by an individual over a longer period of time) and motor or cognitive task-induced state fatigue (i.e., self-reported disabling symptom derived from the two interdependent attributes performance fatigability and perceived fatigability). Thereby, performance fatigability describes a decrease in an objective performance measure, while perceived fatigability refers to the sensations that regulate the integrity of the performer. Although this framework served as a good starting point to unravel the psychophysiology of fatigue, several important aspects were not included and the interdependence of the mechanisms driving performance fatigability and perceived fatigability were not comprehensively discussed. Therefore, the present narrative review aimed to (1) update the fatigue framework suggested by Enoka and Duchateau (Med Sci Sports Exerc 48:2228-38, 2016, [3]) pertaining the taxonomy (i.e., cognitive performance fatigue and perceived cognitive fatigue were added) and important determinants that were not considered previously (e.g., effort perception, affective valence, self-regulation), (2) discuss the mechanisms underlying performance fatigue and perceived fatigue in response to motor and cognitive tasks as well as their interdependence, and (3) provide recommendations for future research on these interactions. We propose to define motor or cognitive task-induced state fatigue as a psychophysiological condition characterized by a decrease in motor or cognitive performance (i.e., motor or cognitive performance fatigue, respectively) and/or an increased perception of fatigue (i.e., perceived motor or cognitive fatigue). These dimensions are interdependent, hinge on different determinants, and depend on body homeostasis (e.g., wakefulness, core temperature) as well as several modulating factors (e.g., age, sex, diseases, characteristics of the motor or cognitive task). Consequently, there is no single factor primarily determining performance fatigue and perceived fatigue in response to motor or cognitive tasks. Instead, the relative weight of each determinant and their interaction are modulated by several factors.

Single-session anodal transcranial direct current stimulation to enhance sport-specific performance in athletes: A systematic review and meta-analysis

BACKGROUND

Transcranial direct current stimulation (tDCS) has emerged as a promising and feasible method to improve motor performance in healthy and clinical populations. However, the potential of tDCS to enhance sport-specific motor performance in athletes remains elusive.

OBJECTIVE

We aimed at analyzing the acute effects of a single anodal tDCS session on sport-specific motor performance changes in athletes compared to sham.

METHODS

A systematic review and meta-analysis was conducted in the electronic databases PubMed, Web of Science, and SPORTDiscus. The meta-analysis was performed using an inverse variance method and a random-effects model. Additionally, two subgroup analyses were conducted (1) depending on the stimulated brain areas (primary motor cortex (M1), temporal cortex (TC), prefrontal cortex (PFC), cerebellum (CB)), and (2) studies clustered in subgroups according to different sports performance domains (endurance, strength, visuomotor skill).

RESULTS

A total number of 19 studies enrolling a sample size of 258 athletes were deemed eligible for inclusion. Across all included studies, a significant moderate standardized mean difference (SMD) favoring anodal tDCS to enhance sport-specific motor performance could be observed. Subgroup analysis depending on cortical target areas of tDCS indicated a significant moderate SMD in favor of anodal tDCS compared to sham for M1 stimulation.

CONCLUSION

A single anodal tDCS session can lead to performance enhancement in athletes in sport-specific motor tasks. Although no definitive conclusions can be drawn regarding the modes of action as a function of performance domain or stimulation site, these results imply intriguing possibilities concerning sports performance enhancement through anodal M1 stimulation.

Relationship between physical activity level and sleep quality with postural control and hemodynamic response in the prefrontal cortex during dual-task performance

Understanding the cortical activation and postural control behavior during dual-task (DT) has been an object of study. However, despite the multiple benefits of exercise and good sleep quality, less is known about the correlation between physical activity (PA) and sleep quality (SQ) on postural control and brain activation under dual-task performance. This study aimed to analyze the correlation between PA level and SQ with postural control performance and hemodynamic response in the prefrontal cortex during the DT performance in young adults. Thirty-four healthy young adults (mean age ± SD = 22.91 ± 3.90 years) participated in this study, and they performed a single-task and cognitive and motor DT using their smartphones. Postural control was assessed using a force plate to record the center of pressure (CoP) data (total excursion of CoP (TOTEX CoP), displacements of the CoP in anterior-posterior (CoP-AP) and medial-lateral (CoP-ML) directions, mean total velocity displacement of CoP (MVELO CoP), mean displacement velocity of CoP in anterior-posterior (MVELO CoP-AP) and medial-lateral (MVELO CoP-ML) directions, amplitude of CoP in anterior-posterior (A-AP) and medial-lateral (A-ML) directions, and 95% confidence ellipse sway area (CEA)). The hemodynamic response was measured by the oxyhemoglobin and deoxyhemoglobin concentrations using the functional near-infrared spectroscopy. The Pittsburg Sleep Quality Index and International Physical Activity Questionnaire-Short Form questionnaires assessed SQ and level of PA, respectively. Results indicated a positive correlation between SQ and cognitive DT cost for CoP-ML (r_s = 0.422, p = 0.013), MVELO CoP-ML (r_s = 0.422, p = 0.013) and A-ML (r_s = 0.579, p < 0.001). There were no significant relations between the other outcomes (p > 0.05). In conclusion, poor sleep quality was associated with a worse postural control performance in CoP-ML, MVELO CoP-ML and A-ML parameters under cognitive dual-task conditions. The differences found in the postural control and hemodynamic response during dual-task performance do not correlate with physical activity level.

Effects of Baduanjin imagery and exercise on cognitive function in the elderly: A functional near-infrared spectroscopy study

Objective

Cognitive function is essential in ensuring the quality of life of the elderly. This study aimed to investigate the effects of Baduanjin imagery and Baduanjin movement (a traditional Chinese health exercise, TCHE) on cognitive function in the elderly using functional near-infrared spectroscopy (fNIRS).

Methods

72 participants with a mean age of 66.92 years (SD = 4.77) were recruited for this study. The participants were randomly assigned to three groups: the Baduanjin imagery, the Baduanjin exercise, and the Control. Stroop task was used to record the accuracy and reaction times, and a near-infrared spectral brain imaging system was used to monitor the brain's oxy-hemoglobin concentration responses.

Results

(1) For the reaction times of Stroop incongruent tasks, the main effect of the test phase (F = 114.076, p < 0.001) and the interaction effect between test phase and group (F = 10.533, p < 0.001) were all significant. The simple effect analysis further demonstrated that the reaction times of the Baduanjin imagery group and Baduanjin exercise group in the post-test was faster than that in the pre-test (ps < 0.001); (2) Analysis of fNIRS data showed the significant interaction effect (F = 2.554, p = 0.013) between the test phase and group in the left dorsolateral prefrontal cortex. Further analysis showed that, during the post-test incongruent tasks, the oxy-Hb variations were significantly higher in participants of the Baduanjin imagery group (p = 0.005) and Baduanjin exercise group (p = 0.002) than in the control group; For the right inferior frontal gyrus, the interaction between the test phase and group was significant (F = 2.060, p = 0.044). Further analysis showed that, during the post-test incongruent tasks, the oxy-Hb variations were significantly higher in participants of the Baduanjin imagery group than in the control group (p = 0.001).

Conclusion

Baduanjin imagery and exercise positively affect cognitive performance; Baduanjin imagery and exercise activated the left dorsolateral prefrontal cortex; Baduanjin imagery activated the right inferior frontal gyrus, while Baduanjin exercise could not.

The effects of acute high-intensity aerobic exercise on cognitive performance: A structured narrative review

It is well established that acute moderate-intensity exercise improves cognitive performance. However, the effects of acute high-intensity aerobic exercise on cognitive performance have not been well characterized. In this review, we summarize the literature investigating the exercise-cognition interaction, especially focusing on high-intensity aerobic exercise. We discuss methodological and physiological factors that potentially mediate cognitive performance in response to high-intensity exercise. We propose that the effects of high-intensity exercise on cognitive performance are primarily affected by the timing of cognitive task (during vs. after exercise, and the time delay after exercise). In particular, cognitive performance is more likely to be impaired during high-intensity exercise when both cognitive and physiological demands are high and completed simultaneously (i.e., the dual-task paradigm). The effects may also be affected by the type of cognitive task, physical fitness, exercise mode/duration, and age. Second, we suggest that interactions between changes in regional cerebral blood flow (CBF), cerebral oxygenation, cerebral metabolism, neuromodulation by neurotransmitters/neurotrophic factors, and a variety of psychological factors are promising candidates that determine cognitive performance in response to acute high-intensity exercise. The present review has implications for recreational, sporting, and occupational activities where high cognitive and physiological demands are required to be completed concurrently.

The mediating role of inhibitory control in the relationship between prefrontal cortex hemodynamics and exercise performance in adults with overweight or obesity

Physical inactivity has been suggested to impair physical performance, cognitive functions and facilitate weight gain. One hypothesis is that long periods of physical inactivity could impair oxygen delivery to the prefrontal cortex (PFC), impairing one's cognitive ability to inhibit unhealthy automated behaviors and, therefore, reduce exercise tolerance. The present study sought to further understand the relationship among PFC hemodynamics, inhibitory control, and exercise tolerance in individuals with low physical fitness levels who are overweight or obese. Thirty-four participants were asked to perform a series of inhibitory control tests (i.e., Stroop task) in one testing session and complete an incremental cycling exercise test with hemodynamic fluctuations of the PFC measured with functional near-infrared spectroscopy in another session. Our results indicate that exercise performance varied with PFC oxygenation. We also found that inhibitory control played a key role mediating the relationship between PFC oxygenation and exercise performance, suggesting that the cognitive ability to inhibit automated responses has an impact on exercise behavior in adults with overweight and obesity.

Brain-muscle interplay during endurance self-paced exercise in normobaric and hypobaric hypoxia

Purpose: Hypoxia is one major environmental factor, supposed to mediate central motor command as well as afferent feedbacks at rest and during exercise. By using a comparison of normobaric (NH) and hypobaric (HH) hypoxia with the same ambient pressure in oxygen, we examined the potential differences on the cerebrovascular and muscular regulation interplay during a self-paced aerobic exercise.

Methods: Sixteen healthy subjects performed three cycling time-trials (250 kJ) in three conditions: HH, NH and normobaric normoxia (NN) after 24 h of exposure. Cerebral and muscular oxygenation were assessed by near-infrared spectroscopy, cerebral blood flow by Doppler ultrasound system. Gas exchanges, peripheral oxygen saturation, power output and associated pacing strategies were also continuously assessed.

Results: The cerebral oxygen delivery was lower in hypoxia than in NN but decreased similarly in both hypoxic conditions. Overall performance and pacing were significantly more down-regulated in HH versus NH, in conjunction with more impaired systemic (e.g. saturation and cerebral blood flow) and prefrontal cortex oxygenation during exercise.

Conclusions: The difference in pacing was likely the consequence of a complex interplay between systemic alterations and cerebral oxygenation observed in HH compared to NH, aiming to maintain an equivalent cerebral oxygen delivery despite higher adaptive cost (lower absolute power output for the same relative exercise intensity) in HH compared to NH.

High-intensity interval training to promote cerebral oxygenation and affective valence during exercise in individuals with obesity

Left/right prefrontal cortex (PFC) activation is linked to positive/negative affects, respectively. Besides, larger left PFC oxygenation during exercise relates to higher cardiorespiratory fitness (CRF). High-intensity interval training (HIIT) is superior to moderate-intensity continuous training (MICT) in improving CRF. The influence of training on PFC oxygenation and affects during exercise in individuals with obesity is, however, currently unknown. Twenty participants with obesity (14 males, 48 ± 8 years, body-mass index = 35 ± 6 kg·m^-2) were randomised to MICT [50% peak work rate (WR_peak)] or HIIT (1-min bouts 100% WR_peak; 3 sessions/week, 8 weeks). Before/after training, participants completed an incremental ergocycle test. Near-infrared spectroscopy and the Feeling Scale assessed PFC oxygenation and affects during exercise, respectively. Improvements in CRF (e.g., WR_peak: 32 ± 14 vs 20 ± 13 W) were greater after HIIT vs MICT (p < 0.05). Only HIIT induced larger left PFC oxygenation (haemoglobin difference from 7 ± 6 to 10 ± 7 μmol) and enhanced affective valence (from 0.7 ± 2.9 to 2.2 ± 2.0; p < 0.05) at intensities ≥ second ventilatory threshold. Exercise-training induced changes in left PFC oxygenation correlated with changes in CRF [e.g., WR_peak (% predicted), r = 0.46] and post-training affective valence (r = 0.45; p < 0.05). HIIT specifically improved left PFC oxygenation and affects during exercise in individuals with obesity. Implementing HIIT in exercise programmes may therefore have relevant implications for the management of obesity, since greater affective response to exercise is thought to be associated with future commitment to physical activity.

Associations of objectively measured movement behavior and cardiorespiratory fitness with mental health and quality of life in older adults with hypertension: an exploratory analysis during the COVID-19 pandemic

Objectives: Herein, we explored the associations of pre-pandemic COVID-19 physical activity (PA), sedentary behavior (SB) and cardiorespiratory fitness (CRF) with mental health and quality of life in older adults with hypertension.Method: Objectively measured PA and SB, perceived stress, depression symptoms, and quality of life were assessed before and during the pandemic in seventeen older adults with hypertension. CRF was assessed before the pandemic by cardiopulmonary exercise testing. Longitudinal and cross-sectional associations were analyzed using the mixed linear model.Results: Pre-pandemic light PA (positive association) and SB (negative association) were associated with quality of life during the pandemic. Higher pre-pandemic CRF was associated with less negative changes in perceived stress, depression symptoms, and quality of life during the pandemic.Conclusion: Our preliminary findings suggest that a healthier pre-pandemic movement behavior (more PA, less SB) and better CRF can mitigate the negative impact of the COVID-19 pandemic on mental health and quality of life in older adults with hypertension.

Effects of different exercise intensities on prefrontal activity during a dual task

The effects of physical exercise on cognitive tasks have been investigated. However, it is unclear how different exercise intensities affect the neural activity. In this study, we investigated the neural activity in the prefrontal cortex (PFC) by varying the exercise intensity while participants performed a dual task (DT). Twenty healthy young adults performed serial subtraction while driving a cycle ergometer. Exercise intensity was set to one of three levels: low, moderate, or high intensity. We did not find any significant change in PFC activity during DT under either the control (no exercise) or low-intensity conditions. In contrast, we observed a significant increase in PFC activity during DT under moderate- and high-intensity conditions. In addition, we observed complex hemodynamics after DT. PFC activity decreased from baseline after DT under the control condition, while it increased under the low-intensity condition. PFC activity remained higher than the baseline level after DT under the moderate-intensity condition but returned to baseline under the high-intensity condition. The results suggest that moderate-intensity exercise with a cognitive load effectively increases PFC activity, and low-intensity exercise may increase PFC activity when combined with a cognitive load.

Acute Effects of Caffeine Supplementation on Physical Performance, Physiological Responses, Perceived Exertion, and Technical-Tactical Skills in Combat Sports: A Systematic Review and Meta-Analysis

Although the effects of caffeine supplementation on combat sports performance have been extensively investigated, there is currently no consensus regarding its ergogenic benefits.This systematic review with meta-analysis aimed to summarize the studies investigating the effects of caffeine supplementation on different aspects of performance in combat sports and to quantitatively analyze the results of these studies to better understand the ergogenic effect of caffeine on combat sports outcomes. A systematic search for randomized placebo-controlled studies investigating the effects of caffeine supplementation on combat sports’ performance was performed through Scopus, Pubmed, Web of Science and Cochrane Library databases up to 18 April 2022. Random-effects meta-analyses of standardized mean differences (Hedge’s g) were performed to analyze the data. Twenty-six studies of good and excellent methodological quality (based on the Pedro scale) fulfilled the inclusion criteria. The meta-analysis results revealed caffeine has a small but evident effect size (ES) on handgrip strength (ES = 0.28; 95% CI: 0.04 to 0.52; p = 0.02), and total number of throws during the special judo fitness test (SJFT) (ES = 0.42; 95% CI: 0.06 to 0.78; p = 0.02). Regarding the physiological responses, caffeine increased blood lactate concentration ([La]) in anaerobic exercise (ES = 1.23; 95% CI: 0.29 to 2.18; p = 0.01) and simulated combat (ES = 0.91; 95% CI: 0.34 to 1.47; p = 0.002). For Heart Rate (HR), caffeine increased HR final (ES = 0.31; 95% CI: 0.11 to 0.52; p = 0.003), and HR 1min (ES = 0.20; 95% CI 0.004 to 0.40; p = 0.045). However, caffeine had no impact on the countermovement jump height, the SJFT index, the judogi strength-endurance test, the number and duration of offensive actions, HR at the end of the fight, and the rating of perceived exertion. Caffeine supplementation may be ergogenic for a range of combat sports aspects involving isometric strength, anaerobic power, reaction time, and anaerobic metabolism. However, supplementation effects might be ineffective under certain circumstances, indicating supplementation needs to take into account the performance metric in question prior to creating a dosing protocol.

Self-Paced Endurance Performance and Cerebral Hemodynamics of the Prefrontal Cortex: A Scoping Review of Methodology and Findings

Recent research has suggested that top-down executive function associated with the prefrontal cortex is key to the decision-making processes and pacing of endurance performance. A small but growing body of literature has investigated the neurological underpinnings of these processes by subjecting the prefrontal cortex to functional near-infrared spectroscopy (fNIRS) measurement during self-paced endurance task performance. Given that fNIRS measurement for these purposes is a relatively recent development, the principal aim of this review was to assess the methodological rigor and findings of this body of research. We performed a systematic literature search to collate research assessing prefrontal cortex oxygenation via fNIRS during self-paced endurance performance. A total of 17 studies met the criteria for inclusion. We then extracted information concerning the methodology and findings from the studies reviewed. Promisingly, most of the reviewed studies reported having adopted commonplace and feasible best practice guidelines. However, a lack of adherence to these guidelines was evident in some areas. For instance, there was little evidence of measures to tackle and remove artifacts from data. Lastly, the reviewed studies provide insight into the significance of cerebral oxygenation to endurance performance and the role of the prefrontal cortex in pacing behavior. Therefore, future research that better follows the guidelines presented will help advance our understanding of the role of the brain in endurance performance and aid in the development of techniques to improve or maintain prefrontal cortex (PFC) oxygenation to help bolster endurance performance.

The Effect of Think Aloud on Performance and Brain Oxygenation During Cycling – An Exploratory Study

In this study, we aimed to investigate the effect of Think Aloud (TA) on performance in trained and untrained participants, using functional Near Infrared Spectroscopy, during incrementally paced cycling. A mixed design was implemented with cycling expertise (10 untrained vs. 9 trained) as the between groups variable and trial stage (5 stages of increasing effort), and condition (silent vs. TA) as within groups independent variables (IVs). Dependent measures were changes in cortical oxygenation (O₂Hb) in 12 areas of the prefrontal cortex (PFC) and physiological indicators of percentage heart rate maximum (%HRmax), average power output (APO), peak power output (PPO), rate of perceived exertion (RPE) and blood lactate ([La]b) over time. Trained cyclists had higher APO and significantly higher PPO from stages 2–5, in addition to a greater increase in PPO over the duration of the test (range 168W–480 W vs. 133W–313 W). There were significant main effects of stage on %HRmax, Bla and RPE (p < .001), with effect sizes (ήp²) ranging from .31 to .97. On average, HRmax%, [La]b and RPE were significantly lower after stage 2 onwards within the TA trial than the silent trial, even though similar power outputs were obtained. Thus, the TA trial elicited a better pacing strategy. There was no main effect of group on changes in O₂Hb, though O₂Hb did change as a function of stage in four areas of the PFC, and as a function of condition in one area. In this first study to assess the effects of TA on performance during self-paced cycling, TA did not disrupt performance outcomes at low through to high levels of physical exertion for either untrained or trained participants.

Acute effects of mindfulness-based intervention on athlete cognitive function: An fNIRS investigation

BACKGROUND

Mindfulness-based intervention (MBI) as a psychological treatment is adopted in the sports field, but its effect during competition has not been explored. This study investigated the acute effect of a brief MBI on athletes' cognitive function after a 45-min, lab-based soccer protocol.

METHODS

In a single-blind randomized counter-balanced crossover design, 17 male soccer players completed two main trials-an MBI trial and a control trial. The MBI trial was provided with a brief MBI after 45-min exercise; the control trial was instead assigned a travel-related audio to listen to at that time. In each main trial, cognitive function (i.e., Stroop task for inhibition; Corsi-block tapping task for working memory), salivary cortisol, blood lactate and mental fatigue were measured at baseline (pretest) and after the intervention (posttest). The cerebral oxygenation status was recorded using functional near-infrared spectroscopy during the cognitive function test.

RESULTS

The brief MBI improved working memory performance in terms of both reaction time (pre vs. post, P = 0.02, d = 0.71) and accuracy (pre vs. post, P = 0.009, d = 0.58), supported by eliciting increased oxyhemoglobin concentration in the prefrontal cortex of the brain. Whereas a slightly better cognitive performance for MBI trial than control trial at posttest (P = 0.37, d = 0.32) accompanied by a lower oxyhemoglobin concentration. A lower mental fatigue level (P = 0.05, d = 0.6) and lower cortisol concentration (P = 0.04, d = 0.65) were observed in the MBI trial than in the control trial after the intervention at posttest. The decreased cortisol concentration correlated with increased inhibition performance in the MBI trial.

CONCLUSION

The acute effect of MBI on athletes' mental fatigue and cortisol concentration was detected, and the beneficial effect on working memory was preliminarily supported. In general, MBI is recommended to be adopted at half-time of a soccer game.

A Novel Intensity-Based Approach to Increasing Prefrontal Cerebral Oxygenation by Walking Exercise

Regional cerebral blood flow (rCBF) increases after moderately intense exercise and is significantly correlated with cognitive function. However, no intensity-based physiological indicator for enhancing rCBF during low- to-moderate-intensity exercise has been proposed. The purpose of this study was to develop a physiological indicator housed in a wearable device to determine whether low-to-moderate intensity walking can increase rCBF. A cross-sectional study with four parallel arms was performed. Each of 114 participants was randomly assigned to either the moderate, low-to-moderate, low, or very low walking intensity groups. A novel dynamic cardiac force meter (CFM) was used to quantify walking intensity. Heart rate and hemoencephalography (HEG) were measured during each phase of the session. Compared to baseline, HEG significantly increased in both the submaximal exercise and recovery phases in members of the low-to-moderate intensity group but not the very low intensity group. Low-to-moderate intensity walking improves prefrontal cerebral blood oxygenation. The present results demonstrate the usefulness of a dynamic CFM housed in a wearable device for quantifying the intensity of walking exercise aimed at increasing prefrontal blood oxygenation. The results of the study may help guide further development of exercise strategies for brain disease patients and the ageing population.

Brain oxygenation during multiple sets of isometric and dynamic resistance exercise of equivalent workloads: Association with systemic haemodynamics

Brain function relies on sufficient blood flow and oxygen supply. Changes in cerebral oxygenation during exercise have been linked to brain activity and central command. Isometric- and dynamic-resistance exercise-(RE) may elicit differential responses in systemic circulation, neural function and metabolism; all important regulators of cerebral circulation. We examined whether (i) cerebral oxygenation differs between isometric- and dynamic-RE of similar exercise characteristics and (ii) cerebral oxygenation changes relate to cardiovascular adjustments occurring during RE. Fourteen men performed, randomly, an isometric-RE and a dynamic-RE of similar characteristics (bilateral-leg-press, 2-min×4-sets, 30% of maximal-voluntary-contraction, equivalent tension-time-index/workload). Cerebral-oxygenation (oxyhaemoglobin-O₂Hb; total haemoglobin-tHb/blood-volume-index; deoxyhemoglobin-HHb) was assessed by NIRS and beat-by-beat haemodynamics via photoplethysmography. Cerebral-O₂Hb and tHb progressively increased from the 1st to 4th set in both RE-protocols (p < 0.05); HHb slightly decreased (p < 0.05). Changes in NIRS-parameters were similar between RE-protocols within each exercise-set (p = 0.91-1.00) and during the entire protocol (including resting-phases) (p = 0.48-0.63). O₂Hb and tHb changes were not correlated with changes in systemic haemodynamics. In conclusion, cerebral oxygenation/blood-volume steadily increased during multiple-set RE-protocols. Isometric- and dynamic-RE of matched exercise characteristics resulted in similar prefrontal oxygenation/blood volume changes, suggesting similar cerebral haemodynamic and possibly neuronal responses to maintain a predetermined force.

Effects of Cardiorespiratory Fitness on Cerebral Oxygenation in Healthy Adults: A Systematic Review

Introduction

Exercise is known to improve cognitive functioning and the cardiorespiratory hypothesis suggests that this is due to the relationship between cardiorespiratory fitness (CRF) level and cerebral oxygenation. The purpose of this systematic review is to consolidate findings from functional near-infrared spectroscopy (fNIRS) studies that examined the effect of CRF level on cerebral oxygenation during exercise and cognitive tasks.

Methods

Medline, Embase, SPORTDiscus, and Web of Science were systematically searched. Studies categorizing CRF level using direct or estimated measures of V̇O_2max and studies measuring cerebral oxygenation using oxyhemoglobin ([HbO₂]) and deoxyhemoglobin ([HHb]) were included. Healthy young, middle-aged, and older adults were included whereas patient populations and people with neurological disorders were excluded.

Results

Following PRISMA guidelines, 14 studies were retained following abstract and full-text screening. Cycle ergometer or treadmill tests were used as direct measures of CRF, and one study provided an estimated value using a questionnaire. Seven studies examined the effects of CRF on cerebral oxygenation during exercise and the remaining seven evaluated it during cognitive tasks. Increased [HbO₂] in the prefrontal cortex (PFC) was observed during cognitive tasks in higher compared to lower fit individuals. Only one study demonstrated increased [HHb] in the higher fit group. Exercise at submaximal intensities revealed increased [HbO₂] in the PFC in higher compared to lower fit groups. Greater PFC [HHb] was also observed in long- vs. short-term trained males but not in females. Primary motor cortex (M1) activation did not differ between groups during a static handgrip test but [HHb] increased beyond maximal intensity in a lower compared to higher fit group.

Conclusion

Consistent with the cardiorespiratory hypothesis, higher fit young, middle-aged, and older adults demonstrated increased cerebral oxygenation compared to lower fit groups. Future research should implement randomized controlled trials to evaluate the effectiveness of interventions that improve CRF and cerebral oxygenation longitudinally.

Enhancing the Cognitive Effects of Flavonoids With Physical Activity: Is There a Case for the Gut Microbiome?

Age-related cognitive changes can be the first indication of the progression to dementias, such as Alzheimer’s disease. These changes may be driven by a complex interaction of factors including diet, activity levels, genetics, and environment. Here we review the evidence supporting relationships between flavonoids, physical activity, and brain function. Recent in vivo experiments and human clinical trials have shown that flavonoid-rich foods can inhibit neuroinflammation and enhance cognitive performance. Improved cognition has also been correlated with a physically active lifestyle, and with the functionality and diversity of the gut microbiome. The great majority (+ 90%) of dietary flavonoids are biotransformed into phytoactive phenolic metabolites at the gut microbiome level prior to absorption, and these prebiotic flavonoids modulate microbiota profiles and diversity. Health-relevant outcomes from flavonoid ingestion may only be realized in the presence of a robust microbiome. Moderate-to-vigorous physical activity (MVPA) accelerates the catabolism and uptake of these gut-derived anti-inflammatory and immunomodulatory metabolites into circulation. The gut microbiome exerts a profound influence on cognitive function; moderate exercise and flavonoid intake influence cognitive benefits; and exercise and flavonoid intake influence the microbiome. We conclude that there is a potential for combined impacts of flavonoid intake and physical exertion on cognitive function, as modulated by the gut microbiome, and that the combination of a flavonoid-rich diet and routine aerobic exercise may potentiate cognitive benefits and reduce cognitive decline in an aging population, via mechanisms mediated by the gut microbiome. Mechanistic animal studies and human clinical interventions are needed to further explore this hypothesis.

Effects of Acute Moderate- and High-Intensity Aerobic Exercise on Oxygenation in Prefrontal Cortex of Male Methamphetamine-Dependent Patients

The aim of this study was to explore the influence of different intensities of acute aerobic exercise on brain activation in male methamphetamine (MA)-dependent patients during exercise. Twenty MA-dependent patients were divided randomly into two groups participating in 35 min of either moderate- or high-intensity aerobic exercise. Functional near-infrared spectral imaging (fNIRS) was used to detect hemodynamic changes in prefrontal cortex during the main 25-min exercise stage. The results revealed that high-intensity acute aerobic exercise aroused more cerebral oxygenation changes in the prefrontal cortex and left dorsolateral prefrontal cortex during exercise as compared with moderate-intensity exercise. Furthermore, there was a stronger positive connection observed between orbital frontal cortex and left dorsolateral prefrontal cortex in the high-intensity group than in the moderate-intensity group. Together these results suggest that for submaximal exercise intensities, high-intensity exercise may bring more benefits to male MA-dependent patients than moderate-intensity.

The Exercising Brain: An Overlooked Factor Limiting the Tolerance to Physical Exertion in Major Cardiorespiratory Diseases?

“Exercise starts and ends in the brain”: this was the title of a review article authored by Dr. Bengt Kayser back in 2003. In this piece of work, the author highlights that pioneer studies have primarily focused on the cardiorespiratory-muscle axis to set the human limits to whole-body exercise tolerance. In some circumstances, however, exercise cessation may not be solely attributable to these players: the central nervous system is thought to hold a relevant role as the ultimate site of exercise termination. In fact, there has been a growing interest relative to the “brain” response to exercise in chronic cardiorespiratory diseases, and its potential implication in limiting the tolerance to physical exertion in patients. To reach these overarching goals, non-invasive techniques, such as near-infrared spectroscopy and transcranial magnetic stimulation, have been successfully applied to get insights into the underlying mechanisms of exercise limitation in clinical populations. This review provides an up-to-date outline of the rationale for the “brain” as the organ limiting the tolerance to physical exertion in patients with cardiorespiratory diseases. We first outline some key methodological aspects of neuromuscular function and cerebral hemodynamics assessment in response to different exercise paradigms. We then review the most prominent studies, which explored the influence of major cardiorespiratory diseases on these outcomes. After a balanced summary of existing evidence, we finalize by detailing the rationale for investigating the “brain” contribution to exercise limitation in hitherto unexplored cardiorespiratory diseases, an endeavor that might lead to innovative lines of applied physiological research.

Cerebral and skeletal muscle tissue oxygenation during exercise challenge in children and young adults with sickle cell anaemia

We used near-infrared spectroscopy to examine tissue oxygenation (StO₂₎ during exercise in 17 children and young adults with sickle cell anaemia (SCA) and 13 controls. Patients had lower cerebral StO₂ at all exercise stages and demonstrated significantly greater decreases in cerebral StO₂ later during exercise. Quadriceps StO₂ increased similarly in patients and controls during early exercise, but decreases from baseline were greater in patients during later exercise. At similar workloads, patients demonstrated lower cerebral StO₂ (69·2 ± 6·6 vs. 79·5 ± 5·3%, P < 0·001) and trended towards lower quadriceps StO₂ (67·7 ± 9·0 vs. 73·2 ± 7·9%, P = 0·09) . Further studies of tissue oxygenation during exercise in SCA are warranted.

Impact of Active Breaks in the Classroom on Mathematical Performance and Attention in Elementary School Children

Background: The increasing need to face the problem of sedentarism, especially in the COVID-19 era, induced teachers and researchers to find new intervention methodologies in school context. Active breaks (ABs) include brief periods of physical activity as a part of the curriculum. This study aimed to investigate the AB acute responses on attentive skills and mathematical performance and attention in a primary school. Methods: A total of 141 children (aged 9.61 ± 0.82), divided into six classes, participated in this study. Each class was randomly assigned to three groups on the basis of the type of protocol performed during the three ABs scheduled in a school day: fitness (FIT), creativity (CREAT), and control group (CON). At baseline and at the end of interventions, all participants underwent the Stroop Color and Word test (SCWT) and the math test (MATH) to assess the level of attention and mathematical performance, respectively. The degree of enjoyment was evaluated through the modified Physical Activity Enjoyment Scale. Results: The factorial ANOVA showed significant differences between the FIT and CON in MATH test (p = 0.023) and SCWT (p = 0.034). CREAT and FIT groups showed higher degree of enjoyment than the CON (both ps < 0.001). Conclusions: This study showed a positive acute impact of AB interventions. FIT positively influenced attentive and math performances more than the CREAT, probably due to the correct work/rest ratio and executive rhythm that allowed children to reach a good level of exertion. This report showed that ABs can be a useful and productive activity to be performed between curricular lessons.

Acute effects of exercise on cerebrovascular response and cognitive performance in individuals with stable coronary heart disease

BACKGROUND

Individuals with coronary heart disease (CHD) exhibit cognitive deficits and cerebrovascular dysfunctions, and are at higher risk of developing dementia. Cognitive function in individuals with CHD has never been studied during acute aerobic exercise. Given the increasing popularity of training at high peak power output (PPO), its impact on cerebrovascular and cognitive functions in individuals with CHD should be further studied.

METHOD

Thirty-eight individuals with CHD and 16 healthy controls completed two exercise bouts at 30% and 70% of their individualized PPO on an ergocycle while performing a cognitive task including non-executive and executive conditions. Variations of oxy- deoxy-hemoglobin, and total hemoglobin concentrations were measured on left prefrontal cortex at both PPO using near-infrared spectroscopy.

RESULTS

Cognitive task performances were equivalent between groups at all intensity levels. Individuals with CHD exhibited larger variation of deoxyhemoglobin in the executive condition and larger variation in total hemoglobin concentration in all task conditions compared to healthy controls at 70% of PPO.

CONCLUSION

Exercising at high intensity seems to have a larger impact on cerebral blood volume in CHD patients compared to healthy age-matched controls. Higher exercise intensity has negative impacts on cerebral blood volume variations during a cognitive task in CHD patients and could potentially lead to other neurocognitive dysfunctions. Other studies are needed to determine if a cognitive task administered during an exercise test could help identify individuals with CHD at higher risk of developing cognitive decline.

Prefrontal cortex activation during incremental inspiratory loading in healthy participants

We aimed to investigate whether changes in prefrontal cortex (PFC) oxyhemoglobin (O₂Hb) and deoxyhemoglobin (HHb) associates with inspiratory muscle effort during inspiratory threshold loading (ITL) in healthy participants. Participants performed an incremental ITL. Breathing pattern, partial pressure of end-tidal CO₂ (P_ETCO₂), mouth pressure and O₂Hb and HHb over the right dorsolateral PFC, sternocleidomastoid (SCM), and diaphragm/intercostals (Dia/IC) were monitored. Fourteen healthy participants (8 men; 29 ± 5 years) completed testing. Dyspnea was higher post- than pre-ITL (5 ± 1 vs. 0 ± 1, respectively; P<0.05). PFC O₂Hb increased (P < 0.001) and HHb decreased (P = 0.001) at low loads but remained stable with increasing ITL intensities. PFC total hemoglobin increased at task failure compared to rest. SCM HHb increased throughout increasing intensities. SCM and Dia/IC total hemoglobin increased in the at task failure compared to rest. P_ETCO₂ did not change (P = 0.528). PFC is activated early during the ITL but does not show central fatigue at task failure despite greater dyspnea and an imbalance of SCM oxygen demand and delivery.

Prefrontal Cortex Oxygenation During Endurance Performance: A Systematic Review of Functional Near-Infrared Spectroscopy Studies

Introduction: A myriad of factors underlie pacing-/exhaustion-decisions that are made during whole-body endurance performance. The prefrontal cortex (PFC) is a brain region that is crucial for decision-making, planning, and attention. PFC oxygenation seems to be a mediating factor of performance decisions during endurance performance. Nowadays, there is no general overview summarizing the current knowledge on how PFC oxygenation evolves during whole-body endurance performance and whether this is a determining factor.

Methods: Three electronic databases were searched for studies related to the assessment of PFC oxygenation, through near-IR spectroscopy (NIRS), during endurance exercise. To express PFC oxygenation, oxygenated (HbO₂) and deoxygenated hemoglobin (HHb) concentrations were the primary outcome measures.

Results: Twenty-eight articles were included. Ten articles focused on assessing prefrontal oxygenation through a maximal incremental test (MIT) and 18 focused on using endurance tasks at workloads ranging from low intensity to supramaximal intensity. In four MIT studies measuring HbO₂, an increase of HbO₂ was noticed at the respiratory compensation point (RCP), after which it decreased. HbO₂ reached a steady state in the four studies and increased in one study until exhaustion. All studies found a decrease or steady state in HHb from the start until RCP and an increase to exhaustion. In regard to (non-incremental) endurance tasks, a general increase in PFC oxygenation was found while achieving a steady state at vigorous intensities. PCF deoxygenation was evident for near-to-maximal intensities at which an increase in oxygenation and the maintenance of a steady state could not be retained.

Discussion/Conclusion: MIT studies show the presence of a cerebral oxygenation threshold (ThCox) at RCP. PFC oxygenation increases until the RCP threshold, thereafter, a steady state is reached and HbO₂ declines. This study shows that the results obtained from MIT are transferable to non-incremental endurance exercise. HbO₂ increases during low-intensity and moderate-intensity until vigorous-intensity exercise, and it reaches a steady state in vigorous-intensity exercise. Furthermore, ThCox can be found between vigorous and near-maximal intensities. During endurance exercise at near-maximal intensities, PFC oxygenation increases until the value exceeding this threshold, resulting in a decrease in PFC oxygenation. Future research should aim at maintaining and improving PFC oxygenation to help in improving endurance performance and to examine whether PFC oxygenation has a role in other performance-limiting factors.

Acute aerobic exercise to recover from mental exhaustion - a randomized controlled trial

PURPOSE

Prolonged periods of intense cognitive activity lead to a state of mental exhaustion. While widespread strategies to recover from mental exhaustion (i.e., watching TV) are non-effective, aerobic exercise seems to be a promising approach. This can be explained by the acute and chronic aerobic exercise-induced benefits on the central nervous system.

METHODS

This study investigated the potential of a single bout of moderate aerobic exercise (65-75% of each participants' individual V˙O2peak) to recover from experimentally induced mental exhaustion. A randomized controlled trial on healthy adults (N = 99) was conducted. They performed 60 min of a cognitively demanding test battery, in order to induce mental exhaustion. Subsequently, they were randomized to one of three treatments: 30 min of moderate aerobic exercise on a cycle ergometer, 30 min of a simple lower body stretching routine (= active control treatment) or watching a popular sitcom (= passive control treatment). Cognitive flexibility performance, mood, tiredness, restlessness, self-perceived cognitive capacity, and motivation were assessed before and after treatment.

RESULTS

The empirical results showed that moderate aerobic exercise led to a better recovery for cognitive flexibility (mean difference divided by pooled standard deviation, Cohen's d= 0.737), mood (d= 0.405), tiredness (d= 0.480), self-perceived cognitive capacity (d= 0.214), and motivation (d= 0.524) compared to active control treatment. Moderate aerobic exercise was also more effective than passive control treatment (d= 0.102 - 0.286) with the exemption of tiredness (d= 0.015) and restlessness (d = -0.473).

CONCLUSION

In conclusion, this study suggests that a single bout of acute aerobic exercise supports regeneration of cognitive flexibility performance and of subjective well-being. This holds true not just compared to artificial active control treatment but also compared to widespread leisure time activity, namely watching TV.

The effects of standing in tutorial group meetings on learning: A randomized controlled trial

BACKGROUND

Standing desks have been brought into the education environment to reduce sedentary behavior among students. The current study explored the effects of standing in tutorial group meetings on learning among undergraduate students.

METHODS

Ninety-six participants were randomly allocated to a Sit or Stand group, with 2 h tutorial group meetings scheduled, once or twice per week, for nine weeks. Learning was analyzed using exam grades, concept maps, and tutorial interactions.

RESULTS

Overall, the Sit and Stand groups did not differ from each other in terms of learning, measured through their exam, concept map, and the use of learning-oriented interactions.

CONCLUSION

Standing in tutorial group meetings neither enhanced nor compromised learning. Considering the health risks associated with prolonged sedentary behavior, offering standing tutorial group meetings to undergraduate students is a recommended solution to break up prolonged sedentary behavior and encourage more physical activity, while maintaining the learning performance of students.

EEG evidence for enhanced attentional performance during moderate-intensity exercise

Research on attentional control within real-world contexts has become substantially more feasible and thus frequent over the past decade. However, relatively little is known regarding how these processes may be influenced by common naturalistic behaviors such as engaging in physical activity, which is thought to modulate the availability of neurometabolic resources. Here, we used an event-related potential (ERP) approach to determine whether various intensities of aerobic exercise might affect the concurrent performance of attentional control mechanisms. Participants performed an additional-singleton visual search task across three levels of aerobic activity while seated on a stationary bicycle: at rest, during moderate-intensity exercise, and during vigorous-intensity exercise. In addition to behavioral measures, attentional processing was assessed via lateralized ERPs referencing target selection (PCN) and distractor suppression (P_D ) mechanisms. Whereas engaging in exercise resulted in speeded response times overall, moderate-intensity exercise was found to uniquely eliminate the expression of distractor interference by the PCN while also giving rise to an unanticipated distractor-elicited Ppc. These findings demonstrate workload-specific and object-selective influences of aerobic exercise on attentional processing, providing insights not only for approaching attention in real-world contexts but also for understanding how attentional resources are used overall.

Effects of Transcranial Direct Current Stimulation on Cycling Time Trial Performance and Prefrontal Cortex Activation

Background: Transcranial direct current stimulation (tDCS) is a neuromodulatory technique that delivers low levels of a constant current via scalp electrodes to specifically targeted areas of the brain. The effects of tDCS on whole-body exercise performance has been of interest in recent literature. The purpose of the current investigation was to investigate if tDCS, administered via Halo Sport, influences time trial performance in trained cyclists, and if changes in exercise performance are associated with prefrontal cortex (PFC) activation and/or muscle oxygenation (SmO2). Methods: Twelve recreationally trained cyclists volunteered to participate in a crossover study design involving two 10-kilometer time trials following 20 min of tDCS or a sham condition. Results: t-tests showed there was no significant difference in performance (time to completion) or physiological measures (blood lactate (BL) concentration, heart rate (HR), SmO2, PFC oxygenation) between the Halo and sham conditions. Conclusions: These results indicate that the application of tDCS via Halo Sport does not induce changes in exercise performance or related physiological parameters during a 10-kilometer cycling time trial.

Differences in cerebral oxygenation during exercise in patients with idiopathic pulmonary fibrosis with and without exertional hypoxemia: does exercise intensity matter?

INTRODUCTION AND OBJECTIVES

Patients with idiopathic pulmonary fibrosis (IPF) present respiratory derangements at rest and during exercise, accompanied by exercise intolerance. Some patients may develop profound exertional desaturation even without resting hypoxemia. Evidence suggests the involvement of reduced cerebral-oxygenation in exercise intolerance. We aimed to examine (i) differences in cerebral-oxygenation during exercise between IPF patients with and without isolated exertional desaturation, (ii) whether the impairments in cerebral-oxygenation are detected at similar exercise intensity, and (iii) correlations between cerebral-oxygenation indices, disease severity, and 6-min walk test (6MWT).

MATERIALS AND METHODS

Patients with IPF (n = 24; 62.1 ± 9.3 years) without resting hypoxemia underwent cardiopulmonary exercise testing (CPET) with cerebral-oxygenation monitoring via near-infrared-spectroscopy (NIRS). Βased on their pulse-oxymetry saturation (SpO₂) during CPET, patients were divided into the "exertional-desaturators" group (SpO_2nadir≤89% and ≥6% drop in SpO₂) and the "non-exertional-desaturators" group (SpO_2nadir≥90% and ≤5% drop).

RESULTS

During CPET, the "exertional-desaturators" group exhibited lower oxygenated-hemoglobin (-0.67 ± 1.48 vs. 0.69 ± 1.75 μmol/l; p < 0.05) and higher deoxygenated-hemoglobin (1.67 ± 1.13 vs. 0.17 ± 0.62 μmol/l; p < 0.001) than the "non-exertional-desaturators" group. A different pattern (p < 0.01) in cerebral-oxygenation responses was observed in the two groups. In exertional-desaturators oxygenated-hemoglobin declined below baseline even at low/moderate-intensity exercise (p < 0.05), whereas, in non-exertional-desaturators cerebral-oxygenation declined (p < 0.05) at high-intensity exercise. Cerebral-NIRS indices correlated (p < 0.05) with CPET-duration, dyspnea, diffusion capacity, and 6MWT.

CONCLUSIONS

During incremental exercise, patients with IPF and exertional desaturation present a significant decline in cerebral-oxygenation even during low-intensity exercise. Our findings support the implementation of longer-duration rehabilitation programs in IPF so that lower intensity exercise can be applied at the initial stages. (NCT03683082).

The Association Between Generalized Anxiety Disorder and Resting-State Prefrontal Cortex Oxygenation Is Modified by Self-Reported Physical Activity: Results From The Irish Longitudinal Study on Ageing

Individuals with anxiety disorders exhibit lower intrinsic functional connectivity between prefrontal cortical areas and subcortical regions. The prefrontal cortex (PFC) is sensitive to the acute and chronic effects of physical activity (PA), while the anxiolytic effects of PA are well known. The current study examined the association of generalized anxiety disorder (GAD) and its interaction with PA, with resting-state, left PFC oxygenation. This cross-sectional study used data from participants (N = 2444) from The Irish Longitudinal Study on Ageing, a nationally representative prospective study of community-living adults aged 50 and older in Ireland. The Composite International Diagnostic Interview Short-Form determined fulfillment of criteria for GAD. The short-form International Physical Activity Questionnaire determined adherence to the World Health Organization PA guidelines. Resting-state, left PFC oxygenation was continuously measured via a Portalite. Tissue saturation index (TSI) was calculated as the ratio of oxygenated hemoglobin to total tissue hemoglobin (expressed as a percentage) for the final minute of a 5-minute supine-rest period. Multivariable linear regression quantified associations of GAD with TSI in the total population and population stratified by PA status. Participants with GAD had lower TSI (b = -1.416, p = .008) compared to those without GAD. However, this association was modified by PA. Among participants who met the PA guidelines, TSI did not differ according to GAD status (b = -0.800, p = .398). For participants who did not meet the guidelines, TSI was significantly lower among those with GAD (b = -1.758, p = .004). These findings suggest that PA may help to protect brain health among older adults with GAD.