Exercise and Executive Function during Follicular and Luteal Menstrual Cycle Phases

A single bout of aerobic exercise does not alter inhibitory control preparatory set cerebral hemodynamics: Evidence from the antisaccade task

A single bout of exercise improves executive function (EF) and is a benefit - in part -attributed to an exercise-mediated increase in cerebral blood flow enhancing neural efficiency. Limited work has used an event-related protocol to examine postexercise changes in preparatory phase cerebral hemodynamics for an EF task. This is salient given the neural efficiency hypothesis' assertion that improved EF is related to decreased brain activity. Here, event-related transcranial Doppler ultrasound was used to measure pro- (saccade to target) and antisaccades (saccade mirror-symmetrical target) preparatory phase middle cerebral artery velocity (MCAv) prior to and immediately after 15-min of aerobic exercise. Antisaccades produced longer reaction times (RT) and an increased preparatory phase MCAv than prosaccades - a result attributed to greater EF neural activity for antisaccades. Antisaccades selectively produced a postexercise RT reduction (ps < 0.01); however, antisaccade preparatory phase MCAv did not vary from pre- to postexercise (p=0.53) and did not correlate with the antisaccade RT benefit (p = 0.31). Accordingly, results provide no evidence that improved neural efficiency indexed via functional hyperemia is linked to a postexercise EF behavioural benefit. Instead, results support an evolving view that an EF benefit represents the additive interplay between interdependent exercise-mediated neurophysiological changes.

Menstrual cycle status does not impact exercise-based changes in cerebral blood flow or executive function benefits

A single bout of exercise enhances executive function (EF) and may relate to an increase in cerebral blood flow (CBF). A limitation in the current literature is that biologically female participants are underrepresented given some evidence that changes in hormone levels across the menstrual cycle impact physiological and psychological variables. Here, biologically female participants completed separate single bouts of moderate intensity exercise (80% of estimated lactate threshold) during the follicular (FOL) and luteal (LUT) phases of their menstrual cycle. In addition, biologically male participants completed a same duration/intensity exercise session. Middle cerebral artery velocity (MCAv) was used to estimate CBF and pre- and postexercise EF was assessed via the antisaccade task. Results showed that resting MCAv was larger in the LUT than FOL phase; however, the exercise-mediated increase in MCAv was equivalent between menstrual cycle phases, and between female and male participants. Antisaccade reaction times reliably decreased from pre- to postexercise and frequentist and non-frequentist statistics demonstrated that the magnitude of the decrease was equivalent across FOL and LUT phases, and between female and male participants. Thus, results evince that menstrual cycle status should not serve as a basis limiting biologically female participants' inclusion in research examining exercise and EF.

Effects of the menstrual cycle on the performance of female football players. A systematic review

Background

Women's football has been booming for a few years now, which has led to an increase in the expectation of the players' performance, leading to a more detailed study of women's physiology in the field of sports.

Objectives

To analyze the scientific evidence on the influence of menstruation on the performance of female footballers, as well as to analyze the methodological quality of the studies included in this review.

Materials and methods

The possible hormonal effects of the menstrual cycle phases on the performance of female footballers were analyzed. The databases used to conduct the searches were Pubmed, Scopus, Virtual Health Library, Web of Science, EBSCO and the Cochrane Library. All included studies met the inclusion criteria. The Cochrane risk of bias tool was used. This systematic review protocol was registered at the International Prospective Register of Systematic Reviews (PROSPERO: CRD42023390652).

Results

A total of nine clinical trials were included in this review. A low quality of evidence was observed in the studies. Not all the results support the idea that the menstrual cycle phases can alter the performance of female footballers.

Conclusion

This systematic review shows that there is a great deal of controversy about the influence of the menstrual cycle phases on the performance of female footballers. Studies are focused on solely biological factors and gender is normally no part of those studies. Further research with larger samples, and taking not only biological but also sociological factors, are necessary to determine the effects of menstruation on the performance of female footballers.

10-min exposure to a 2.5% hypercapnic environment increases cerebral blood blow but does not impact executive function

Space travel and exploration are associated with increased ambient CO2 (i.e., a hypercapnic environment). Some work reported that the physiological changes (e.g., increased cerebral blood flow [CBF]) associated with a chronic hypercapnic environment contributes to a "space fog" that adversely impacts cognition and psychomotor performance, whereas other work reported no change or a positive change. Here, we employed the antisaccade task to evaluate whether transient exposure to a hypercapnic environment influences top-down executive function (EF). Antisaccades require a goal-directed eye movement mirror-symmetrical to a target and are an ideal tool for identifying subtle EF changes. Healthy young adults (aged 19-25 years) performed blocks of antisaccade trials prior to (i.e., pre-intervention), during (i.e., concurrent) and after (i.e., post-intervention) 10-min of breathing factional inspired CO2 (FiCO2) of 2.5% (i.e., hypercapnic condition) and during a normocapnic (i.e., control) condition. In both conditions, CBF, ventilatory and cardiorespiratory responses were measured. Results showed that the hypercapnic condition increased CBF, ventilation and end-tidal CO2 and thus demonstrated an expected physiological adaptation to increased FiCO2. Notably, however, null hypothesis and equivalence tests indicated that concurrent and post-intervention antisaccade reaction times were refractory to the hypercapnic environment; that is, transient exposure to a FiCO2 of 2.5% did not produce a real-time or lingering influence on an oculomotor-based measure of EF. Accordingly, results provide a framework that - in part - establishes the FiCO2 percentage and timeline by which high-level EF can be maintained. Future work will explore CBF and EF dynamics during chronic hypercapnic exposure as more direct proxy for the challenges of space flight and exploration.

Distinct cortical haemodynamics during squat-stand and continuous aerobic exercise do not influence the magnitude of a postexercise executive function benefit

A single bout of aerobic exercise benefits executive function (EF). A potential mechanism for this benefit is an exercise-mediated increase in cerebral blood flow (CBF) that elicits vascular endothelial shear-stress improving EF efficiency. Moderate intensity continuous aerobic exercise (MCE) asymptotically increases CBF, whereas continuous body weight squat-stand exercise (SSE) provides a large amplitude oscillatory response. Some work has proposed that an increase in CBF oscillation amplitude provides the optimal shear-stress for improving EF and brain health. We examined whether a large amplitude oscillatory CBF response associated with a single bout of SSE imparts a larger postexercise EF benefit than an MCE cycle ergometer protocol. Exercise changes in middle cerebral artery velocity (MCAv) were measured via transcranial Doppler ultrasound to estimate CBF, and pre- and postexercise EF was assessed via the antisaccade task. MCE produced a steady state increase in MCAv, whereas SSE produced a large amplitude MCAv oscillation. Both conditions produced a postexercise EF benefit that null hypothesis and equivalence tests showed to be comparable in magnitude. Accordingly, we provide a first demonstration that a single bout of SSE benefits EF; however, the condition's oscillatory CBF response does not impart a larger benefit than a time- and intensity-matched MCE protocol.

Look into my eyes: What can eye-based measures tell us about the relationship between physical activity and cognitive performance?

BACKGROUND

There is a growing interest to understand the neurobiological mechanisms that drive the positive associations of physical activity and fitness with measures of cognitive performance. To better understand those mechanisms, several studies have employed eye-based measures (e.g., eye movement measures such as saccades, pupillary measures such as pupil dilation, and vascular measures such as retinal vessel diameter) deemed to be proxies for specific neurobiological mechanisms. However, there is currently no systematic review providing a comprehensive overview of these studies in the field of exercise-cognition science. Thus, this review aimed to address that gap in the literature.

METHODS

To identify eligible studies, we searched 5 electronic databases on October 23, 2022. Two researchers independently extracted data and assessed the risk of bias using a modified version of the Tool for the assEssment of Study qualiTy and reporting in EXercise (TESTEX scale, for interventional studies) and the critical appraisal tool from the Joanna Briggs Institute (for cross-sectional studies).

RESULTS

Our systematic review (n = 35 studies) offers the following main findings: (a) there is insufficient evidence available to draw solid conclusions concerning gaze-fixation-based measures; (b) the evidence that pupillometric measures, which are a proxy for the noradrenergic system, can explain the positive effect of acute exercise and cardiorespiratory fitness on cognitive performance is mixed; (c) physical training- or fitness-related changes of the cerebrovascular system (operationalized via changes in retinal vasculature) are, in general, positively associated with cognitive performance improvements; (d) acute and chronic physical exercises show a positive effect based on an oculomotor-based measure of executive function (operationalized via antisaccade tasks); and (e) the positive association between cardiorespiratory fitness and cognitive performance is partly mediated by the dopaminergic system (operationalized via spontaneous eye-blink rate).

CONCLUSION

This systematic review offers confirmation that eye-based measures can provide valuable insight into the neurobiological mechanisms that may drive positive associations between physical activity and fitness and measures of cognitive performance. However, due to the limited number of studies utilizing specific methods for obtaining eye-based measures (e.g., pupillometry, retinal vessel analysis, spontaneous eye blink rate) or investigating a possible dose-response relationship, further research is necessary before more nuanced conclusions can be drawn. Given that eye-based measures are economical and non-invasive, we hope this review will foster the future application of eye-based measures in the field of exercise-cognition science.

Do executive function performance, gaze behavior, and pupil size change during incremental acute physical exercise?

Several studies have investigated the interaction between acute physical exercise and cognitive performance. However, few studies have investigated this issue during acute high-intensity exercise. In the present study, we evaluated executive functions (EFs) during incremental exercise in three different intensities [below lactate threshold (LT), at LT, and above LT], measuring EFs performance, gaze behavior, and pupil diameter. Twenty subjects were familiarized with the EFs test and participated in a graded maximal exercise test on a cycle ergometer on the first visit. On the second visit, they performed the EFs task at rest and while exercising at three different intensities using mobile eye-tracking glasses. Our results showed that the psychophysiological measures differed between the conditions. Regarding EFs performance, during exercise above LT, the subjects showed worse accuracy when compared with rest (p < .001) and below LT (p < .001). In addition, the response time (RT) at LT and above LT was shorter than in the rest condition (p < .050). Further, RT was faster (p = .002) in the above LT than in the below LT condition. In addition, the gaze behavior measures indicated that exercise, independently of the intensity, improves the number of fixations with shorter fixation durations compared to the rest condition (p < .050). Additionally, we found no significant differences in average and peak pupil diameter between conditions. In conclusion, exercise at LT improves the EFs performance while exercising above LT worsens EFs performance. However, there were no significant differences in average and peak pupil diameter between conditions.

Are COMT Val158Met (rs4680), DRD2 TaqIA (rs1800497), and BDNF Val66Met (rs6265) polymorphisms associated with executive functions performance at rest and during physical exercise?

Executive functions (EFs) encompass a wide array of cognitive processes, which appear to be influenced by genetic variants of the COMT, DRD2/ANKK1, and BDNF polymorphisms. The present study aimed to investigate whether COMT Val158Met (rs4680), DRD2/ANKK1 (rs1800497), and BDNF Val66Met (rs6265) polymorphisms were associated with EFs assessed at rest and during moderate acute physical exercise. Sixty physically active individuals underwent four laboratory visits. First, they filled out the pre-exercise survey, researchers collected their anthropometric data, and then performed a maximal cardiopulmonary exercise test. In the second and third sessions, participants performed EFs test in a randomized order: while the individual was seated on a cycle ergometer without pedaling (i.e., rest condition); and during physical exercise (pedaling for 30 minutes at moderate intensity before starting the EFs test during exercising). On the fourth day, blood samples were drawn. Our results showed that the response time of the COMT Val homozygotes group was significantly shorter than the COMT Met-carrier group [t(39.78) = 2.13, p = .039,d = 0.56] at rest condition. No significant association was found for the other analyses (DRD2/ANKK1 and BDNF). In conclusion, the present study suggests that COMT Val158Met (rs4680) polymorphisms may be associated with EFs at rest condition. However, further studies are needed to validate this association.

A Single Bout of Exercise Provides a Persistent Benefit to Cognitive Flexibility

Purpose: A single bout of exercise enhances activity within the cortical networks that support executive function. It is, however, unclear whether exercise improves each core component of executive function and for how long a putative benefit might persist. Method: In Experiment 1, participants completed 20-min of aerobic exercise (via cycle ergometer) and cognitive flexibility-a core component of executive function-was examined pre-exercise, and at immediate, 30- and 60-min post-exercise assessments. Experiment 2 entailed a non-exercise control (i.e., participants sat on the ergometer without exercising) involving the same timeline of cognitive flexibility assessment. Cognitive flexibility was measured via stimulus-driven (SD) and minimally delayed (MD) saccades arranged in an AABB paradigm. SD and MD saccades require a response at target onset and after target offset, respectively, with the latter requiring executive control. Work has shown that reaction times for a SD saccade preceded by a MD saccade are longer than when a SD saccade is preceded by its same task-type, whereas the converse switch does not influence performance (i.e., the unidirectional switch-cost). Results: Experiment 1 showed a unidirectional switch-cost at each assessment; however, the switch-cost magnitude was decreased at immediate and 30-min assessments compared to the pre- and 60-min assessments. In contrast, Experiment 2 did not elicit a change in switch-cost magnitude across the different assessments. Discussion/Conclusion: Thus, a single-bout of exercise benefitted the cognitive flexibility component of executive function in the immediate and 30-min post-exercise assessments.

Passive exercise increases cerebral blood flow velocity and supports a postexercise executive function benefit

Executive function entails high-level cognitive control supporting activities of daily living. Literature has shown that a single-bout of exercise involving volitional muscle activation (i.e., active exercise) improves executive function and that an increase in cerebral blood flow (CBF) may contribute to this benefit. It is, however, unknown whether non-volitional exercise (i.e., passive exercise) wherein an individual's limbs are moved via an external force elicits a similar executive function benefit. This is a salient question given that proprioceptive and feedforward drive from passive exercise increases CBF independent of the metabolic demands of active exercise. Here, in a procedural validation participants (n = 2) used a cycle ergometer to complete separate 20-min active and passive (via mechanically driven flywheel) exercise conditions and a non-exercise control condition. Electromyography showed that passive exercise did not increase agonist muscle activation or increase ventilation or gas exchange variables (i.e., V̇O₂ and V̇CO₂ ). In a main experiment participants (n = 28) completed the same exercise and control conditions and transcranial Doppler ultrasound showed that active and passive exercise (but not the control condition) increased CBF through the middle cerebral artery (ps <.001); albeit the magnitude was less during passive exercise. Notably, antisaccade reaction times prior to and immediately after each condition showed that active (p < .001) and passive (p = .034) exercise improved an oculomotor-based measure of executive function, whereas no benefit was observed in the control condition (p = .85). Accordingly, results evince that passive exercise 'boosts' an oculomotor-based measure of executive function and supports convergent evidence that increased CBF mediates this benefit.

The Development of Executive Functions in High-Level Female Soccer Players

Executive functions (EFs) are higher-level cognitive functions that help keep an individual's goal-oriented thoughts and actions aligned. While many studies have shown the importance of EFs in sport, a limitation in this literature is that female participants have been underrepresented. In this mixed-longitudinal study, we examined the development of EFs in a cohort of high performing female athletes. We collected data over five seasons in a large sample of 175 female soccer players (aged 12-29 years old) from the U14 - senior age groups of a professional German soccer club. Players undertook a large battery of cognitive tasks aimed at measuring higher-level cognitive functioning: a sustained attention task, a stop-signal task, a Go-No-go test, an N-Back Test, and both a 180°- and 360°-multiple-object tracking task. We used linear and non-linear mixed effect regressions to examine the relationship between age and EFs. Second order polynomial curves explained many of these relationships between age and EFs compared to their linear relationships. Negatively accelerated curves reveal that these players' cognitive abilities mainly developed before players reached early adulthood, with a performance plateau evident at around 21 years of age. Age explained low to moderate proportions of the variance in EFs (<1-50%), while cognitive development across playing positions was not a strong contributor to this variance (M = 2.1, SD = 2.1%). We concluded that age has a negatively accelerated relationship with EFs in female soccer players that does not differ between playing positions. These data support the idea that athletes require only a reasonable level of EF ability to perform at the highest level of their sport. Our research raises new questions regarding the validity of current EF measurement methods for inferring information about in-game use of these cognitive abilities.

Evaluating the efficacy of an iPad® app in determining a single bout of exercise benefit to executive function

We examined the efficacy and feasibility of an iPad® app used at-home in identifying a postexercise benefit to executive function. The iPad® app required simple reaching movements mirror-symmetrical to an exogenously presented target (i.e., antipointing) and is a task that lab-based behavioral and neuroimaging work has shown to provide a valid measure of the response inhibition component of executive function. Fifty English-speaking individuals (18 female, age range 18-26 years of age) completed the iPad® app before and immediately after a 20-min session of heavy-intensity aerobic exercise, and on a separate day completed the app prior to and following a 20-min non-exercise control condition. Results showed antipointing reaction times (RTs) in the exercise condition decreased by an average of 18 ms postexercise (p < 0.001) with an observed large effect size (d_z = 0.90), whereas control condition pre- and post-assessment RTs did not reliably differ (p = 0.12, d_z = 0.22) and were within an equivalence boundary (p < 0.005). Further, pre-assessment exercise and control condition antipointing RTs were within an equivalence boundary (p < 0.05). Accordingly, a simple iPad® app provides the requisite resolution to detect subtle executive function benefits derived from a single bout of exercise.

Impact of Inter-Set Short Rest Interval Length on Inhibitory Control Improvements Following Low-Intensity Resistance Exercise in Healthy Young Males

The length of rest interval between sets (i.e., inter-set rest interval) is an important variable for resistance exercise program. However, the impact of the inter-set rest interval on improvements in cognitive function following resistance exercise remains unknown. In this study, we compared the effect of short rest interval (SRI) vs. long rest interval (LRI) protocols on post-exercise cognitive inhibitory control (IC) improvements induced by low-intensity resistance exercise. Twenty healthy, young males completed both SRI and LRI sessions in a crossover design. The bilateral knee extensor low-intensity resistance exercise was programed for six sets with 10 repetitions per set using 40% of one-repetition maximum. The inter-set rest interval lengths for SRI and LRI protocols were set for 1 and 3min, respectively. The color-word Stroop task (CWST) was administrated at six time points: baseline, pre-exercise, immediate post-exercise, and every 10min during the 30-min post-exercise recovery period. The levels of blood lactate, which may be an important determinant for improving IC, throughout the 30-min post-exercise recovery period were significantly higher following SRI protocol than following LRI protocol (p=0.002 for interaction effect). In line with this result, large-sized decreases in the reverse-Stroop interference score, which represent improved IC, were observed immediately after SRI protocol (d=0.94 and 0.82, respectively, vs. baseline and pre-exercise) as opposed to the moderate-sized decreases immediately after LRI protocol (d=0.62 and 0.66, respectively, vs. baseline and pre-exercise). Moreover, significant decreases in the reverse-Stroop interference score were observed from 10 to 30min after SRI protocol (all ps<0.05 vs. baseline and/or pre-exercise), whereas no such decrease was observed after LRI protocol. Furthermore, the degree of decreases in the reverse-Stroop interference score throughout the 30-min post-exercise recovery period was significantly greater in SRI protocol than in LRI protocol (p=0.046 for interaction effect). We suggest that the SRI protocol is more useful in improving post-exercise IC, potentially via greater circulating lactate levels, compared to the LRI protocol. Therefore, the inter-set rest interval length may be an important variable for determining the degree of cognitive function improvements following resistance exercise in healthy young males.

A single bout of moderate intensity exercise improves cognitive flexibility: evidence from task-switching

Executive function entails the core components of response  inhibition, working memory and cognitive flexibility. An accumulating literature has shown that a single bout of exercise improves the response inhibition  and working memory components of executive function; however, limited work has examined a putative exercise-related improvement to cognitive flexibility. To address this limitation, Experiment 1 entailed a 20-min session of moderate intensity aerobic exercise (via cycle ergometer), and pre- and post-exercise cognitive flexibility was examined via a task-switching paradigm involving alternating pro- and antisaccades (AABB: A = prosaccade, B = antisaccade). In Experiment 2, participants sat on the cycle ergometer without exercising (i.e., rest break) and the same AABB paradigm was examined pre- and post-break. We used an AABB pro- and antisaccade paradigm because previous work has shown that a prosaccade preceded by an antisaccade exhibits a reliable-and large magnitude-increase in reaction time, whereas the converse switch does not (i.e., the unidirectional prosaccade switch-cost). Experiment 1 showed a unidirectional prosaccade switch-cost pre-exercise (p = .012)-but not post-exercise (p = .30), and a two one-sided t test indicated that the latter comparison was within an equivalence boundary (p < .01). In contrast, Experiment 2 revealed a unidirectional prosaccade switch-cost at pre- and post-break assessments (ps < .01). Accordingly, our results indicate that a single bout of exercise improves cognitive flexibility and provides convergent evidence that exercise improves global components of executive function.

Increased cerebral blood flow supports a single-bout postexercise benefit to executive function: evidence from hypercapnia

A single bout of aerobic exercise improves executive function; however, the mechanism for the improvement remains unclear. One proposal asserts that an exercise-mediated increase in cerebral blood flow (CBF) enhances the efficiency of executive-related cortical structures. To examine this, participants completed separate 10-min sessions of moderate- to heavy-intensity aerobic exercise, a hypercapnic environment (i.e., 5% CO₂), and a nonexercise and nonhypercapnic control condition. The hypercapnic condition was included because it produces an increase in CBF independent of metabolic demands. An estimate of CBF was achieved via transcranial Doppler ultrasound and near-infrared spectroscopy that provided measures of middle cerebral artery blood velocity (BV) and deoxygenated hemoglobin (HHb), respectively. Exercise intensity was adjusted to match participant-specific changes in BV and HHb associated with the hypercapnic condition. Executive function was assessed before and after each session via antisaccades (i.e., saccade mirror-symmetrical to a target) because the task is mediated via the same executive networks that demonstrate task-dependent modulation following single and chronic bouts of aerobic exercise. Results showed that hypercapnic and exercise conditions were associated with comparable BV and HHb changes, whereas the control condition did not produce a change in either metric. In terms of antisaccade performance, the exercise and hypercapnic, but not control, conditions demonstrated improved postcondition reaction times (RT), and the magnitude of the hypercapnic and exercise-based increase in estimated CBF was reliably related to the postcondition improvement in RT. Accordingly, results evince that an increase in CBF represents a candidate mechanism for a postexercise improvement in executive function.NEW & NOTEWORTHY Single-bout aerobic exercise "boosts" executive function, and increased cerebral blood flow (CBF) has been proposed as a mechanism for the benefit. In this study, participants completed 10 min of aerobic exercise and 10 min of inhaling a hypercapnic gas, a manipulation known to increase CBF independently of metabolic demands. Both exercise and hypercapnic conditions improved executive function for at least 20 min. Accordingly, an increase in CBF is a candidate mechanism for the postexercise improvement in executive function.

A Single Bout of Aerobic Exercise Provides an Immediate "Boost" to Cognitive Flexibility

Executive function includes the core components of working memory, inhibitory control, and cognitive flexibility. A wealth of studies demonstrate that working memory and inhibitory control improve following a single bout of exercise; however, a paucity - and equivocal - body of work has demonstrated a similar benefit for cognitive flexibility. Cognitive flexibility underlies switching between different attentional- and motor-related goals, and a potential limitation of previous work examining this component in an exercise context is that they included tasks involving non-executive processes (i.e., numerosity, parity, and letter judgments). To address this issue, Experiment 1 employed a 20-min bout of aerobic exercise and examined pre- and immediate post-exercise cognitive flexibility via stimulus-driven (SD) and minimally delayed (MD) saccades ordered in an AABB task-switching paradigm. Stimulus-driven saccades are a standard task requiring a response at target onset, whereas MD saccades are a non-standard and top-down task requiring a response only after the target is extinguished. Work has shown that RTs for a SD saccade preceded by a MD saccade are longer than when a SD saccade is preceded by its same task-type, whereas the converse switch does not influence performance (i.e., the unidirectional switch-cost). Experiment 1 yielded a 28 ms and 8 ms unidirectional switch-cost pre- and post-exercise, respectively (ps < 0.001); however, the magnitude of the switch-cost was reduced post-exercise (p = 0.005). Experiment 2 involved a non-exercise control condition and yielded a reliable and equivalent magnitude unidirectional switch-cost at a pre- (28 ms) and post-break (26 ms) assessment (ps < 0.001). Accordingly, a single-bout of exercise improved task-switching efficiency and thereby provides convergent evidence that exercise provides a global benefit to the core components of executive function.