Attentive Processes and Blood Lactate in the Sambo.

BACKGROUND: Sambo is a martial art and combat sport that originated in the Soviet Union. There are two main stiles, Sport Sambo and Combat Sambo which resembles modern mixed martial arts. Very little literature is available about physiological aspects of Sambo and, in particular, on the possible effects on cognitive domains. The purpose of the present research was to determine if there is a correlation between a blood lactate increase and the intensity and/or selectivity of attentions. METHODS: Sixteen male athletes practicing Sambo for at least 5 years participated voluntarily in the study. Each athlete had to sustain, with an interval of one week, both a Sport Sambo match and a Combat Sambo match, each lasting 5 min. Blood lactate levels as well as attentive capacities were evaluated at three different times: at rest, i.e., 5 min before the start of the session (pre), at end of the session and 15 min after its conclusion. Reaction time protocol was used to evaluate the intensity of attention, whereas divided attention was assessed for analyzing the selectivity of attention together with errors and omissions. RESULTS: Concerning Sport Sambo, blood lactate was 1.66 mmol/L (±0.55 SD) before the session, reached a mean value of 3.40 mmol/L (±0.45 SD) at the end of the session (end) and returned to values similar to initial ones (a mean value of 1.98 mmol/L (±0.37 SD) after 15 min (15-end). None of the attentive parameters examined, showed statistically significant differences. Conversely, for Combat Sambo, it was found a significant increase in blood lactate levels that went from 1.66 mmol/L (±0.55 SD) before the session (pre), to 4.76 mmol/L (±0.60 SD) at the end (end) and then back to values similar to those observed before the session 15 min after its conclusion (15-end), i.e., 1.97 mmol/L (±0.37 SD); however, after a Combat Sambo session increases in blood lactate were associated with significant worsening of attentional mechanisms. CONCLUSIONS: In conclusion, in all the participants, the worsening of attentional mechanisms was observed only after the Combat Sambo session in which blood lactate values exceeded 4 mmol/L. This figure, also known as the Onset of Blood Lactate Accumulation (OBLA), is commonly used to determine the anaerobic threshold.

Influences of Blood Lactate Levels on Cognitive Domains and Physical Health during a Sports Stress. Brief Review.

The present review aims to examine the effects of high blood lactate levels in healthy adult humans, for instance, after a period of exhaustive exercise, on the functioning of the cerebral cortex. In some of the examined studies, high blood lactate levels were obtained not only through exhaustive exercise but also with an intravenous infusion of lactate while the subject was immobile. This allowed us to exclude the possibility that the observed post-exercise effects were nonspecific (e.g., cortical changes in temperature, acidity, etc.). We observed that, in both experimental conditions, high levels of blood lactate are associated with a worsening of important cognitive domains such as attention or working memory or stress, without gender differences. Moreover, in both experimental conditions, high levels of blood lactate are associated with an improvement of the primary motor area (M1) excitability. Outside the frontal lobe, the use of visual evoked potentials and somatosensory evoked potentials allowed us to observe, in the occipital and parietal lobe respectively, that high levels of blood lactate are associated with an amplitude's increase and a latency's reduction of the early components of the evoked responses. In conclusion, significant increases of blood lactate levels could exercise a double-action in the central nervous system (CNS), with a protecting role on primary cortical areas (such as M1, primary visual area, or primary somatosensory cortex), while reducing the efficiency of adjacent regions, such as the supplementary motor area (SMA) or prefrontal cortex. These observations are compatible with the possibility that lactate works in the brain not only as an energy substrate or an angiogenetic factor but also as a true neuromodulator, which can protect from stress. In this review, we will discuss the mechanisms and effects of lactic acid products produced during an anaerobic exercise lactate, focusing on their action at the level of the central nervous system with particular attention to the primary motor, the somatosensory evoked potentials, and the occipital and parietal lobe.

Executive Functions During Submaximal Exercises in Male Athletes: Role of Blood Lactate.

The present study was carried out among 20 healthy young male athletes to determine whether aerobic exercise performed at two different intensities is able to affect executive functions. For this purpose, we used the Stroop Color Word Test (SCWT) to evaluate the ability to inhibit cognitive interference and the Trail Making Test (TMT) to assess organized visual search, set shifting, and cognitive flexibility. Simple Reaction Time (RT), as a measure of perception and response execution, was also evaluated. The experimental protocol included the measure of blood lactate levels with the aim of assessing possible relations between lactate blood values and selected executive functions after a 30-min steady-state test performed at 60% and at 80% of VO2max. The results showed that a 30-min aerobic exercise is not associated with a worsening of executive functions as long as the blood lactate levels stay within the 4 mmol/l threshold.

Postural Control and Stress Exposure in Young Men: Changes in Cortisol Awakening Response and Blood Lactate.

BACKGROUND: It has recently been noticed that the quantity of stress affects postural stability in young women. The study was conducted with the goal of investigating whether increased stress may damagingly effect posture control in 90 young men (71 right-handed and 19 left-handed) while maintaining an upright bipedal posture, while keeping their eyes open or closed. Perceived Stress Scale (PSS) was administered and changes in free cortisol levels were monitored (Cortisol Awakening Response, CAR) in order to evaluate the amount of stress present during awakening, while the Profile of Mood States (POMS) was used to estimate distress on the whole. Posture control was evaluated with the use of a force platform, which, while computing a confidence ellipse area of 95%, was engaged by the Center of Pressure through five stability stations and was sustained for a minimum of 52 s, with and without visual input. Another goal of the experiment was to find out whether or not cortisol increases in CAR were linked with rises of blood lactate levels. RESULTS: CAR, PSS and POMS were found to be extensively related. Furthermore, it has been observed that increases in salivary cortisol in CAR are associated with small but significant increases in blood lactate levels. As expected, stress levels did affect postural stability. CONCLUSIONS: The results of the present study confirm that the level of stress can influence postural stability, and that this influence is principally obvious when visual information is not used in postural control.

Effects of a Bout of Intense Exercise on Some Executive Functions.

The present study examined the effects of an exhaustive exercise on executive functions by using the Stroop Color Word Test (SCWT), Trail Making Test (TMT), A and B, and simple Reaction Time (RT). Thirty adults agreed to participate; 15 participants had a mean age of 24.7 years ± 3.2 Standard Deviation (SD, Standard Deviation) (group YOUNG), while the remaining 15 had a mean age of 58.9 years ± 2.6 SD (group OLD). Each subject performed the cognitive tasks at rest and blood lactate was measured (pre); each subject executed the acute exhaustive exercise and, immediately after the conclusion, executed the cognitive tasks and blood lactate was again measured (end). Cognitive tests were repeated and blood lactate measured 15 min after its conclusion of the exhaustive exercise (post). We observed: (1) a significant positive correlation between blood lactate levels and RT levels; (2) a significant negative relationship between levels of blood lactate and the SCWT mean score; (3) no significant correlation between blood lactate levels and TMT scores (time and errors), both A and B; (4) variations in blood lactate levels, due to exhaustive exercise, and parallel deterioration in the execution of RT and SCWT are significantly more pronounced in the group YOUNG than in the group OLD. The present study supports the possibility that high levels of blood lactate induced by an exhaustive exercise could adversely affect the executive functions pertaining to the prefrontal cortex.

Risk-taking behavior, the second-to-fourth digit ratio and psychological features in a sample of cavers.

BACKGROUND: The risk-taking behavior is largely modulated by the subject's history, its lifestyles, by the characteristics of the situations with which it is compared, and also by the effects of prenatal androgens. Thus, the personality of the single person is a significant predictor of such way of acting. METHODS: The present study aimed to explore the relationship between Digit Ratio Measurement (2D:4D) and personality factors capable to be good predictors for choosing highly risky activities, such as caving. Furthermore, our purpose was to investigate whether 2D:4D ratio is related to cavers' affective states and to assess the personological and emotional features of 34 healthy cavers, aged between 24 and 71 years (M = 39.70, SD = 9.81). RESULTS: Data analysis showed several significant correlations between 2D:4D and Deliberate Risk Taking (RTI) and Precautionary Behavior (RTI), confirming that 2D:4D is a reliable index able to predict risk-taking behaviors. Furthermore, data analysis showed that Conscientiousness and its sub-dimension Scrupulousness (BFQ-2) are recurrent among significant correlations; in particular, the latter reports negative correlations with many factors of POMS. Moreover, all participants seemed to have a good attitude to collaboration, in terms of goal-direct strategy, and an adequate management of negative affective states, useful to maintaining a good level of stress within the group. Finally, the BFQ-2 factor Openness to culture seemed to be a predominant feature in the cavers, and this feature could be considered as predictive in the choice of an activity, such as caving, which requires curiosity, perseverance and a great planning of cave exploration.

Cognitive Deficits and White Matter Alterations in Highly Trained Scuba Divers.

Nitrogen gas (N2), present in the normal atmospheric air, is a potential source of risk for scuba divers. It seems probable that myelin can represent, in hyperbaric conditions, a preferential site for the accumulation of N2 in central nervous system (CNS). The purpose of this study is to verify whether the practice of the scuba diving is capable to determine a damage of the brain white matter (WM) in a dose dependent manner and, consequently, possible deficiency of their cognitive abilities. For this purpose, 54 professional scuba divers (35 men and 19 women), with at least 2,000 dives in their careers, were studied. Possible alterations of brain WM were evaluated in terms of Fractional anisotropy (FA) by using Diffusion Tensor Imaging, whereas possible cognitive impairments were verified by means of neuropsychological testing, by studying: (1) General mental capability (2) Executive functioning; (3) Visuospatial construction such as Rey Complex Figure; (4) Attention and orientation: (5) Selective attention capacity and processing speed ability; (6) Memory. The results showed alteration of the WM in terms of changes in FA; these alterations, statistically significant but quantitatively quite modest, were mainly observed in the WM of the anterior part of the brain, whereas no differences were observed between left and right hemisphere. The alterations of the WM were associated with changes, also in this case statistically significant but quantitatively quite modest, of the cognitive functions, in particular of those dependent on the prefrontal cortex, such as attention and memory function. The present study leads to the conclusion that repeated dives, even performed in compliance with the current decompression tables, can progressively lead in the CNS to the formation of micro-lesions in the myelin sheet capable of altering the functioning of the neuron.

Ergojump evaluation of the explosive strength in volleyball athletes pre- and post-fascial treatment.

It has previously been demonstrated that physiological mechanisms are involved in muscle pain and fatigue, as the nociceptive afferents of the fascial system are able to modulate the afferent response of the central nervous system. The purpose of the present study was to evaluate a sample of volleyball players, and investigate whether osteopathic treatment of the lower limb muscle groups improved the explosive force of the limbs, whilst reducing spasms and tension, releasing tissue strain and correcting posture. A randomized control study was performed to evaluate 57 athletes who underwent fascial manipulative treatment to assess if such treatment affected the muscle strength of the lower limbs. The treatment group demonstrated a statistically significant improvement in the squatting jump test (P<0.0001) and in the counter movement jump test (P<0.0001). Furthermore, the control group did not exhibit any improvement in the squatting jump test (P<0.56) or in the counter movement jump test (P<0.32). The results suggested that correction of the fascial system required a minimum time of 30 days in order to obtain an improvement of fascial mechanics and sports performance. Therefore, use of a fascial protocol during athletic training will help improve the balance of the bands and, as a direct consequence, improve the efficiency of the musculoskeletal system, thereby reducing the risk of injury. It would therefore be advisable to perform osteopathic treatment techniques every two months during an athletic season to maintain the balance of the fascial system and obtain the most efficient results.

Sleep Deprivation and Physiological Responses. A Case Report.

BACKGROUND: The aim of this study was to evaluate the effects of 72-h sleep deprivation on normal daily activities (work, family, and sports), and to investigate whether sleep can be chronically reduced without dangerous consequences. METHODS: The participant in this study was an adult male (age 41 years; mass 69 kg; height 173 cm). During the 72 h, data were collected every 6 h, involving a baseline (pre-deprivation). We monitored various parameters: Oxidative Stress (D-Rom and Bap test), Psychological Responses (test POMS and Measure of Global Stress), Metabolic expenditure (kJ) using a metabolic holter, EEG records, Cortisol, and Catecholamines level. RESULTS: An interesting result was observed in the post-test phase, when a brief moment of deep sleep and total absence of a very deep sleep occurred, while an almost normal condition occurred in the pre-test sleep. CONCLUSION: During the 72-h sleep deprivation, no psycho-physiological stress was recorded. The participant has remained within the threshold of well-being. Only a peak was recorded during the 66th hour, but it was within the wellness threshold.

Digit ratio, personality and emotions in skydivers.

The aim of the present study was investigate if there is an association between second-to-fourth digit length (2D:4D) ratio and personality factors capable of serving as predictors of individual choice towards high-risk activities in a group of experts skydivers; Furthermore, their skills in regulating anxiety and emotions were assessed. The 2D:4D ratio of the right hand of 41 expert skydivers was measured and each of them completed four questionnaires: Big Five Questionnaire-2 (BFQ-2), Profile of Mood States (POMS), State-Trait Anxiety Inventory Form Y (STAI-Y) and Risk-Taking Inventory. Lower 2D:4D ratios did not appear associated with a greater propensity for taking risks but rather with a lower aptitude to assume precautions in unsafe conditions. In fact, the only sub-dimensions of personality, analyzed by the BFQ-2, correlated with the 2D:4D ratio were conscientiousness and agreeableness. Furthermore, prior to launch, the skydiver's level of stress, measured by the POMS, or state anxiety, measured by the STAI-Y, was not significantly correlated with 2D:4D ratio; whereas there was significant positive correlation between 2D:4D values and trait anxiety. Data analysis further revealed that social desirability correlated negatively with state anxiety and total mood disturbance index, and positively with emotion control. The present results suggest that lower 2D:4D ratio may represent a significant predictor of less attentive precautionary behavior when risk-taking.

The 2D:4D ratio is associated with performance in the 'TEACCH program' of subjects with autism spectrum disorder.

Problems arising on the autistic spectrum are more common in male individuals, leading scholars to attempt to determine whether there is a correlation with testosterone levels to which fetuses were exposed during intrauterine life. The aim of the present study was to investigate, through the digit ratio technique, the possible correlation between testosterone exposure during intrauterine life and the achievement of predetermined objectives during the educational program Treatment and Education of Autistic and Related Communication Handicapped Children (TEACCH) in a group of subjects with different forms of autism. The results showed a positive correlation of the TEACCH program and 2D:4D ratio. Therefore, we hypothesize that a base screening may be useful to pinpoint the optimal teaching strategies to obtain the best possible performance from each subject.

Flexibility of Gender Stereotypes: Italian Study on Comparative Gender-consistent and Gender-inconsistent Information / La flexibilidad de los estereotipos de género: estudio italiano sobre la información comparativa congruente e incongruente con el género

The topic of this study is flexibility in gender stereotyping linked to attribution of toys, socio-cognitive traits, and occupations in 160 Italian children aged 6 to 12 years. We used the Gender Toys Choice, the Gender Traits Choice, and the Gender Jobs Choice, a ed set of colored cards containing masculine and feminine stimuli to assign to a male or female or both male and female silhouette (the flexible-choice technique). In order to verify the change of flexibility in gender stereotyping, we made use of four cartoon stories with male and female characters with typical or atypical traits and performing gender-consistent or gender-inconsistent activities. Results indicated that the exposure to cartoon stories with gender-inconsistent information rather than cartoon stories with gender-consistent information increased flexibility in gender stereotyping, showing age differences in favor of children aged 11-12. Implications in relation to the developmental-constructivist approach were noted

Esta investigación aborda la flexibilidad de los estereotipos de género asociados a la atribución de juguetes, rasgos sociocognitivos y ocupaciones en 160 niños italianos de entre 6 y 12 años. Las pruebas utilizadas fueron la elección de juguetes de género, de rasgos de género y de tareas de género, representados en un conjunto seleccionado de tarjetas de colores que utilizan estímulos asociados típicamente al género para asignar a una silueta masculina o femenina o a la vez masculina y femenina (técnica de elección flexible). Para determinar el cambio de flexibilidad de los estereotipos de género, hicimos uso de cuatro historias de dibujos animados con personajes masculinos y femeninos, con rasgos típicos o atípicos, realizando actividades congruentes o incongruentes con el género. Los resultados muestran que la exposición a dibujos animados con información incongruente con el género en lugar de dibujos animados con información congruente con el género aumenta la flexibilidad de los estereotipos de género, habiendo diferencias en los niños entre 11 y 12 años. Se observaron implicaciones en relación con el enfoque del desarrollo constructivista

Bioenergetics and psychological profile of an ultra-endurance walker.

Ultra-endurance walking provides athletes with significant physiological and psychological challenges. In this study ultra-endurance walking races are intended as events where the participants have to cover the largest distance within a given time, usually 24, 36, 48 hours, or longer, keeping the pause time within 5% of the total walking time. The aim of the study was to evaluate the metabolic, bioenergetics, and psychological characteristics of a world record ultra-endurance walker during three different ultra-endurance events characterized by different durations (36 hours, 48 hours and 70 hours). The participant investigated in this study was an experienced male ultra-endurance walker (age 41 years; mass 69 kg; height 173 cm), who used always the Nordic walking technique. During the 70 hours event, our walker broke the "Longest Marathon Nordic Walking" Guinness World Record covering 274 km in 70 hours. An overall time-dependent increase of oxidative stress, as assessed by lipid hydroperoxide levels, was observed in 36 hours and 48 hours events. Speed and metabolic cost of walking decreased rather linearly with walking time over all the three events. The study shows how the walker was able to approach the three different ultra-endurance events characterized by different durations applying physiological, and psychological strategies allowing him to reach the goal of the completion of each ultra-endurance event.

Effects of age and sex on epigenetic modification induced by an acute physical exercise.

It has been observed that, after 2 hours of aerobic exercise, plasma interleukin-6 (IL-6) increases whereas nuclear concentrations of enzyme DNA methyltransferase (DNMT) 3B significantly decreased in peripheral blood mononuclear cells (PBMCs), with no change observed in DNMT3A. The aim of the present study was to detect differences in these changes induced by exercise in plasma IL-6 levels as well as in PBMC nuclear concentrations of DNMT3A and DNMT3B, in relation to age and sex. Four groups were studied: 12 young men (24.8 ±â€Š1.77 years old), 12 young women (23.8 ±â€Š1.81 years old), 12 adult men (45.8 ±â€Š1.82 years old), 12 adult women (mean 44.5 ±â€Š2.07 years old). Participants had to run at 60% of maximal oxygen consumption (VO2max) for 120 minutes, interspersed with sprints at 90% of VO2max for the last 30 seconds of every 10 minutes. About 250 µL of PBMCs (1 × 10 cells) were treated with 100 µL of either pre-exercise plasma or post-exercise plasma and nuclear DNMT3A and DNMT3B concentrations were quantified. No change in nuclear concentration of DNMT3A following the exercise was observed. Conversely, nuclear concentrations of DNMT3B significantly decreased, with a reduction of about 78% in young men, 72% in young women, 61% in adult men, and 53% in adult women. Moreover, a strong positive correlation between the nuclear concentration of DNMT3B in PBMC following stimulation with post-exercise plasma and post-exercise plasma concentrations of IL-6 was observed in all the 4 studied groups. This study confirms that a single bout of endurance exercise is sufficient to decrease nuclear concentrations of DNMT3B and thus protein upregulation. Moreover, the epigenetic mechanisms induced by exercise apparently cause more intense changes in men than in women and that, in both of them, this effect seems to decrease with age.

The role of deep breathing on stress.

The objective of this study was to verify, in a sample of university students, whether a relaxing technique called deep breathing (stress Intervention Functional IFA) is capable to improve the mood and to reduce the levels of stress. Thirty-eight adult healthy subjects (aged between 18 and 28 years) volunteered the study. They were randomly divided in two groups, the Experimental Group (N = 19) and the Control Group (N = 19). The subjects of the Experimental Group were submitted, once per week, to 10 treatment's sessions of Anti-stress Protocol, each lasting 90 min, whereas subjects of the Control Group sat ten times for 90 min, once per week, without practicing any treatment. The psychological state of mood and stress was evaluated using Measurement of Psychological Stress (MSP) and Profile of Mood State (POMS), while the biological profile of the stress was detected by measuring the heart rate and the salivary cortisol. The results obtained from the present research support the possibility that deep breathing technique is capable to induce an effective improvement in mood and stress both in terms of self-reported evaluations (MPS and POMS) and of objective parameters, such as heart rate and salivary cortisol levels. No statistically significant difference was found between men and women.

Attentive processes, blood lactate and CrossFit®.

OBJECTIVES: To analyze the influences of blood lactate produced during a specific session of CrossFit® on intensity and selectivity of attention. The first was evaluated by measuring the reaction time and the second by analyzing divided attention with a dual task. METHODS: Fifteen male professionals of CrossFit® volunteered in the study. The training session was the Workout Of the Day (WOD) called 15.5, marked as: 27-21-15-9 repetitions (without recovery) in term of calories measured by using a rowing ergometer (e.g. 27 rowed calories) and in term of barbell full squats (raising a weight of 43 kg for men and of 29.5 kg for women). Blood lactate, blood glucose, reaction time, execution time of a dual task, number of errors and number of omissions were measured at rest, at the conclusion of the session and 15 minutes after its end. RESULTS: The levels of the blood lactate before the start of the session were considerably higher than those which normally occur at rest (<2 mmol /L), with a mean value of 4.5 mmol /l (± 1.99 SD). At the end of the workout session the blood lactate exhibited a significant increase, reaching a mean value of 13.8 mmol /l (± 1.18 SD) and then returning to values similar to the initial ones after 15 minutes. Blood glucose did not exhibit any statistically significant differences during the session. Reaction time, execution time, number of errors and number of omissions exhibited a significant worsening concomitantly with the increase in blood lactate. CONCLUSION: Athletes practicing CrossFit®, with high levels of blood lactate even at rest, should consequently have attentional performances somewhat limited.

Effects of an Exhaustive Exercise on Motor Skill Learning and on the Excitability of Primary Motor Cortex and Supplementary Motor Area.

We examined, on 28 healthy adult subjects, the possible correlations of an exhaustive exercise, and the consequent high blood lactate levels, on immediate (explicit) and delayed (implicit) motor execution of sequential finger movements (cognitive task). Moreover, we determined with transcranial magnetic stimulation whether changes in motor performance are associated with variations in excitability of primary motor area (M1) and supplementary motor area (SMA). We observed that, after an acute exhaustive exercise, the large increase of blood lactate is associated with a significant worsening of both explicit and implicit sequential visuomotor task paradigms, without gender differences. We also found that, at the end of the exhaustive exercise, there is a change of excitability in both M1 and SMA. In particular, the excitability of M1 was increased whereas that of SMA decreased and, also in this case, without gender differences. These results support the idea that an increase of blood lactate after an exhaustive exercise appears to have a protective effect at level of primary cortical areas (as M1), although at the expense of efficiency of adjacent cortical regions (as SMA).

Unilateral Eye Blinking Arising From the Ictal Ipsilateral Occipital Area.

We report on an 18-month-old boy with unilateral left eye blinking as a single ictal manifestation without facial twitching. The clinical onset of this phenomenon was first recorded (as an occasional event) at age 3 months, and it was overlooked. By age 6 months, the child's blinking increased to almost daily occurrence in clusters: during blinking the infant showed intact awareness and occasional jerks in the upper limbs and right leg. A video-electroencephalography (video-EEG) documented clinical correlation with a focal pattern arising from the left occipital region, and brain magnetic resonance imaging (MRI) revealed severe brain damage, consisting in poroencephalic hollows and increased spaces in the convexities involving a large area of the left cerebral hemisphere. The boy was prescribed sodium valproate (30 mg/kg/d), resulting in drastic reduction of his clinical seizures. Follow-up to his current age documented good general status, with persistent partial right hemilateral seizures. The blinking progressively disappeared, and is no longer recorded. The pathogenic hypotheses of the unilateral ictal blinking include involvement of the ipsilateral cerebral hemisphere and/or the cerebellar pathways. Review of previous reports of unilateral eye blinking, arising from the ictal ipsilateral brain, revealed that different damaged regions may give rise to blinking ictal phenomena, likely via the trigeminal fibres innervating the subdural intracranial structures and the pial vessels in the ipsilateral affected brain. The eye blinking in the present child represents a further example of an ictal phenomenon, which is predictive of the damaged brain region.

Working memory and blood lactate levels.

The accumulation of lactate in the blood after a high-intensity exercise is associated with an increase of lactate extractions by the brain. Previously, a negative influence of blood lactate on attentional processes has been observed. The present study was carried out to examine the association of high blood lactate levels, induced with a maximal cycling, with another cognitive domain: working memory. For evaluation of working memory two different protocols were used: the first (Self-Ordered Pointing Task) capable of analyzing non-spatial working memory requiring the ability to generate and monitor a sequence of responses and the second for evaluating motor working memory necessary to perform a motor task. The study was carried out in 30 students (15 males and 15 females) who performed exhaustive exercise. In each subject, blood lactate was measured and motor as well as non-motor forms of working memory were evaluated before the exercise, at its end as well as 15 min after the exhaustion. It was observed that an increase of blood lactate levels is associated with a worsening of both types of working memory.

Somatosensory evoked potentials and blood lactate levels.

We compared, in 20 subjects, the effects of high blood lactate levels on amplitude and latency of P1, N1, P2 and N2 components of lower limb somatosensory evoked potential (SEP), an useful, noninvasive tool for assessing the transmission of the afferent volley from periphery up to the cortex. SEPs were recorded from CPz located over the somatosensory vertex and referenced to FPz with a clavicle ground. Measurements were carried out before, at the end as well as 10 and 20 min after the conclusion of a maximal exercise carried out on a mechanically braked cycloergometer. After the exercise, P2-N2 amplitudes as well as latency of P1 and N1 components showed small but significant reductions. On the contrary, latency of N2 component exhibited a significant increase after the exercise's conclusion. These results suggest that blood lactate appears to have a protective effect against fatigue, at least at level of primary somatosensory cortex, although at the expense of efficiency of adjacent areas.