Behavior, Intake, Digestion and Milk Yield of Early Lactation Holstein Dairy Cows with Two Levels of Environmental Exposure and Feeding Strategy.

Eighty-four autumn (ACS, n = 45)- and spring (SCS, n = 39)-calved multiparous early lactation Holstein cows were assigned to groups of either: (a) grazing + mixed ration (MR) during partial confinement in outdoor soil-bedded pens with shade (OD-GRZ); (b) grazing + MR during partial confinement in a compost-bedded pack barn with cooling (CB-GRZ); or (c) total confinement fed a totally mixed ration (CB-TMR) in a compost-bedded pack barn. Data were analyzed using the SAS MIXED procedure with significance at p ≤ 0.05. In both seasons, despite behavioral differences (p < 0.05) between the OD-GRZ and CB-GRZ groups (i.e., standing, first grazing meal length, bite rate), the milk and component yields, DM intake, microbial CP output (MCP) and NE efficiency were unaffected by the housing conditions, possibly due to mild weather conditions. The milk yield was substantially higher in the CB-TMR group versus the OD-TMR and CB-TMR groups (p < 0.01) in both ACS (~35%) and SCS (~20%) despite there being no intake differences, without any impact on milk component levels. In ACS, this was associated with a higher MCP, likely due to the higher nutritional value of TMR compared to pasture, which was not the case in SCS. In conclusion, the OD-GRZ group achieved the same milk production as the CB-GRZ group through behavior adaptation, under mild weather conditions, in both calving seasons. The CB-TMR group outperformed the grazing systems in both calving seasons, regardless of the MCP.

Using parent-offspring pairs and trios to estimate indirect genetic effects in education.

We investigated indirect genetic effects (IGEs), also known as genetic nurture, in education with a novel approach that uses phased data to include parent-offspring pairs in the transmitted/nontransmitted study design. This method increases the power to detect IGEs, enhances the generalizability of the findings, and allows for the study of effects by parent-of-origin. We validated and applied this method in a family-based subsample of adolescents and adults from the Lifelines Cohort Study in the Netherlands (N = 6147), using the latest genome-wide association study data on educational attainment to construct polygenic scores (PGS). Our results indicated that IGEs play a role in education outcomes in the Netherlands: we found significant associations of the nontransmitted PGS with secondary school level in youth between 13 and 24 years old as well as with education attainment and years of education in adults over 25 years old (ß = 0.14, 0.17 and 0.26, respectively), with tentative evidence for larger maternal IGEs. In conclusion, we replicated previous findings and showed that including parent-offspring pairs in addition to trios in the transmitted/nontransmitted design can benefit future studies of parental IGEs in a wide range of outcomes.

Sexual behaviour of young rams is improved and less stressful after intranasal administration of oxytocin.

The aim of this study was to determine if intranasal administration of oxytocin modifies sexual behaviour and the stress response in young rams during sexual tests with ewes in oestrus. Ten rams were used in a cross-over design. At Day 0, the control group (CG, n = 5) received isotonic saline spray intranasally, and the treated group (OTG, n = 5) received oxytocin (24 IU) intranasally, 40 min before the sexual test. At Day 15, the groups were reversed. In each sexual test (20 min) with an oestrous-induced ewe, the sexual behaviour of the young rams was recorded. Serum cortisol concentrations were determined before and after the test. Less flehmen was observed in the OTG, but mounts with ejaculation were increased. The OTG presented lower serum cortisol concentration than the CG. In conclusion, intranasal administration of oxytocin modified the sexual behaviour of rams, evidenced by a decrease in flehmen behaviour and an increase in mounts with ejaculation, making sexual activity more efficacious. In addition, the treatment decreased the stress response of the rams in the sexual tests. Therefore, intranasal administration of oxytocin could be used to increase sexual activity in rams, and with less stress, providing better welfare conditions.

Lung diffusing capacity after different modalities of exercise at sea level and hypobaric simulated altitude of 4.000 m / Capacidad de difusión pulmonar bajo diferentes modalidades de ejercicio a nivel del mar y en hipoxia hipobárica simulada de 4.000 m

Introduction: Lung diffusion capacity of carbon monoxide (DLCO) provides a measure of gas transfer in the lungs, which increase in relation to exercise and decrease in the presence of lung interstitial disease. The aim of this study is to evaluate the changes in lung diffusion after anaerobic and aerobic exercise in a cycle ergometer. Material and method: The participants were 9 healthy active subjects, including six females and three males (age: 24.3 ± 3.1 years). Lung diffusion capacity for carbon monoxide (DLCO) was studied under two different protocols: In the first day, DLCO was measured at SL at rest (SL-R), after 30-s maximal exercise (SL-ANA), and after 15-min moderate continuous exercise (SL-AER). In the second day, DLCO was evaluated at rest at SL, and then at HA (4,000 m) at rest (HA-R) and after 30-min of moderate interval exercise (HA-AER). Results: There was an increase in DLCO from rest to after SL-ANA (32.5 ± 6.4 to 40.3 ± 11.6 mL·min-1·mmHg-1, P = 0.027). In the second day, DLCO was evaluated at rest at SL, and then at HA (4,000 m) at rest (HA-R) and after 30-min of moderate interval exercise (HA-AER). During HA exposure, there was no changes in DLCO, either at HA-R, or after HA-AER. Conclusions: Lung diffusion capacity largely increased after 30-s maximal exercise in a cycle ergometer, although the O2-dependence is small during this type of anaerobic exercise. Thus, exercise intensity may be a key modulator of the changes in lung diffusing capacity in relation to exercise.(AU)

Introducción: La difusión pulmonar para el monóxido de carbono (DLCO) proporciona una medida de la transferencia de gas en los pulmones, que aumenta con relación al ejercicio y disminuye en presencia de una lesión intersticial pulmonar. El objetivo de este estudio es fue evaluar los cambios en la difusión pulmonar después de un ejercicio aeróbico y anaeróbico en cicloergómetro. Material y método: Los participantes fueron 9 sujetos físicamente activos, incluyendo seis mujeres (edad: 24,6 ± 3,6 años) y tres hombres (edad: 23,7 ± 1,5 años). La DLCO se estudió bajo dos protocolos diferentes: El primer día, la DLCO fue medida a nivel del mar en reposo (SL-R), después de un esfuerzo máximo de 30 segundos (SL-ANA), y después de un ejercicio moderado continuo de 15-min (SL-AER). El segundo día, la DLCO fue evaluada a nivel del mar en reposo (SL-R, y luego en altitud (4.000 m) en reposo (HA-R) y después de un ejercicio interválico de 30 minutos (HA-AER). Resultados: Se produjo un aumento de la DLCO de la SL-R a la SL-ANA (32,5 ± 6,4 a 40,3 ± 11,6 mL·min-1·mmHg-1, p = 0,027). En el segundo día, la DLCO no se modificó después de la exposición en altitud, ya sea en reposo a 4.000 m (HA-R) o después del ejercicio interválico moderado a dicha intensidad (HA-AER). Conclusiones: La difusión pulmonar aumentó ampliamente después de un esfuerzo máximo de 30 segundos en cicloergómetro, aunque la dependencia del oxígeno en este tipo de esfuerzos es pequeña. La intensidad del esfuerzo es un modulador determinante en las modificaciones de la difusión pulmonar con relación al ejercicio.(AU)

Characterizing Creative Thinking and Creative Achievements in Relation to Symptoms of Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder.

Previous research on ADHD and ASD has mainly focused on the deficits associated with these conditions, but there is also evidence for strengths. Unfortunately, our understanding of potential strengths in neurodevelopmental conditions is limited. One particular strength, creativity, has been associated with both ADHD and ASD. However, the distinct presentations of both conditions beg the question whether ADHD and ASD associate with the same or different aspects of creativity. Therefore, the current study investigated the links between ADHD and ASD symptoms, creative thinking abilities, and creative achievements. To investigate the spectrum of ADHD and ASD symptoms, self-reported ADHD and ASD symptoms, convergent (Remote Associations Test) and divergent thinking (Alternative Uses Task) and creative achievements (Creative Achievement Questionnaire) were assessed in a self-reportedly healthy sample of adults (n = 470). We performed correlation analysis to investigate the relation between ADHD/ASD symptoms and creativity measures. In a second phase of analysis, data from an adult ADHD case-control study (n = 151) were added to investigate the association between ADHD symptoms and divergent thinking in individuals with and without a diagnosis of ADHD. Our analysis revealed that having more ADHD symptoms in the general population was associated with higher scores on all the outcome measures for divergent thinking (fluency, flexibility, and originality), but not for convergent thinking. Individuals with an ADHD diagnosis in the case-control sample also scored higher on measures of divergent thinking. Combining data of the population based and case-control studies showed that ADHD symptoms predict divergent thinking up to a certain level of symptoms. No significant associations were found between the total number of ASD symptoms and any of the creativity measures. However, explorative analyses showed interesting links between the ASD subdomains of problems with imagination and symptoms that relate to social difficulties. Our findings showed a link between ADHD symptoms and divergent thinking abilities that plateaus in the clinical spectrum of symptoms. For ASD symptoms, no relation was found with creativity measures. Increasing the knowledge about positive phenotypes associated with neurodevelopmental conditions and their symptom dimensions might aid psychoeducation, decrease stigmatization and improve quality of life of individuals living with such conditions.

Acute Changes in Lung Diffusing Capacity After Training in Elite Swimmers / Cambios en la capacidad de difusión pulmonar después del entrenamiento en nadadores de élite

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Severe Hypoxic Exercise Does Not Impair Lung Diffusion in Elite Swimmers.

García, Iker, Franchek Drobnic, Casimiro Javierre, Victoria Pons, and Ginés Viscor. Severe hypoxic exercise does not impair lung diffusion in elite swimmers. High Alt Med Biol. 22:90-95, 2021. Background: Exercise performed at high altitude may cause a subclinical pulmonary interstitial edema that can worsen gas exchange function. This study aimed to evaluate whether there are changes in alveolar-capillary diffusion after exercise during a short-term exposure to hypobaric hypoxia in elite swimmers. Materials and Methods: Seven elite swimmers (age: 20.4 ± 1.4 years, height: 1.78 ± 10.8 m, body mass: 69.7 ± 11.1 kg) participated in the study. Diffusing capacity of the lungs for carbon monoxide (DLCO), transfer coefficient of carbon monoxide, pulse oximeter oxygen saturation (SpO2), and heart rate (HR) were measured at sea level at rest (SL-R), and after a short-term hypobaric hypoxia exposure (4,000 m), both at rest (HA-R) and at the end of moderate interval exercise (HA-E). Results: The combined exposure to high altitude and exercise did not change DLCO from SL-R to HA-R, or HA-E (43.8 ± 9.8 to 41.3 ± 10.5 to 42.4 ± 8.6 ml minutes-1 mmHg-1, p = 0.391). As expected, elite swimmers showed large decrease in SpO2 (72 ± 5; p < 0.001) and increase in HR (139 ± 9 beats minutes-1; p < 0.003) after HA-E. Conclusions: An acute high-altitude exposure combined with submaximal exercise does not change alveolar-capillary diffusion in elite swimmers.

Lung capacity and alveolar gas diffusion in aquatic athletes: Implications for performance and health

Background: The diffusion capacity of carbon monoxide (DLCO) provides a measure of gas transfer in the lungs. Endurance training does not increase lung volumes or diffusion in land-based athletes. However swimmers have larger lungs and better diffusion capacity than other matched athletes and controls.PurposeThe aim of this study was to evaluate pulmonary alveoli-capillary diffusion and lung volumes in elite aquatic athletes, specifically swimmers, artistic swimmers and water polo players.MethodsThe participants were 64 international level aquatic athletes including 31 swimmers (11 female and 20 male), 12 artistic swimmers (only female), and 21 water polo players (10 female and 11 male). The single-breath method was used to measure DLCO and pulmonary parameters.ResultsThe main finding of this study is that DLCO is high in aquatic athletes, clearly above their reference values, both in females (33.4±9.4mLmin−1·mmHg−1; 135%) and males (48.0±5.83mLmin−1·mmHg−1; 148%). There was no difference in DLCO between female swimmers, artistic swimmers and water polo players (34.7±8.3 to 33.4±4.0 to 32.1±5.6mLmin−1·mmHg−1), but male swimmers had a higher DLCO compared to water polo players (50.4±5.3 to 43.4±7.0, p=0.014).ConclusionsAquatic athletes have larger lungs and better diffusion capacity than the percentage predicted by age and height. Therefore, swimming-based sports could help to improve pulmonary function in many different segments of the population. (AU)

Changes in Lung Diffusing Capacity of Elite Artistic Swimmers During Training.

Artistic swimmers (AS) are exposed to repeated apnoeas in the aquatic environment during high intensity exercise provoking specific physiological responses to training, apnoea, and immersion. This study aimed to evaluate the changes in lung diffusing capacity in AS pre-, mid- and post-training in a combined session of apnoeic swimming, figures and choreography. Eleven elite female AS from the Spanish national team were the study's participants. The single-breath method was used to measure lung diffusing capacity for carbon monoxide (DLCO) and one-way repeated measures ANOVA was utilized to evaluate the statistical analysis. Basal values of DLCO were higher than normal for their age and height (33.6±4.9 mL·min-1·mmHg-1; 139±19%) and there were a significant interaction between DLCO and AS training (ŋ2 p=0.547). After the apnoeic swimming (mid-training) there was an increase in DLCO from basal to 36.7±7.3 mL·min-1·mmHg-1 (p=0.021), and after the figures and choreography (post-training) there was a decrease compared to mid-training (32.3±4.6 mL·min-1·mmHg-1, p=0.013). Lung diffusing capacity changes occur during AS training, including a large increase after apnoeic swimming. There were no differences in lung diffusing capacity from pre- to post-training, although large inter-individual variability was observed.

Swimming exercise transiently decrease lung diffusing capacity in elite swimmers.

BACKGROUND: Swimmers have larger lungs and a higher diffusion capacity than other athletes, but it remains unknown whether swimming exercise changes lung diffusing properties. This study aimed to evaluate modifications in pulmonary alveolar-capillary diffusion after swimming exercise. METHODS: The participants were 21 elite level swimmers, including 7 females and 14 males, with a training volume of 45-70 kilometers of swimming per week. The single-breath method was used to measure the lung diffusing capacity for carbon monoxide (DLCO and the transfer coefficient of the lungs for carbon monoxide (KCO) before and after 10 training sessions over 4 weeks along 207 pre- to postevaluations. RESULTS: Swimming training consistently decreased lung diffusion capacity during the follow-up period, both DLCO (44.4±8.1 to 43.3±8.9 mL·min-1·mmHg-1, P=0.047, ŋ2p=0.55) and KCO (5.92±0.79 to 5.70±0.81 mL·min-1·mmHg-1·L-1, P=0.003, ŋ2p=0.75). CONCLUSIONS: Elite swimmers experience a subclinical impairment in lung diffusing capacity after swimming exercise, but the stress caused by swimming on the lungs and the acute reduction in DLCO does not lead to physiological dysfunction.

Lung Diffusion in a 14-Day Swimming Altitude Training Camp at 1850 Meters.

Swimming exercise at sea level causes a transient decrease in lung diffusing capacity for carbon monoxide (DLCO). The exposure to hypobaric hypoxia can affect lung gas exchange, and hypoxic pulmonary vasoconstriction may elicit pulmonary oedema. The purpose of this study is to evaluate whether there are changes in DLCO during a 14-day altitude training camp (1850 m) in elite swimmers and the acute effects of a combined training session of swimming in moderate hypoxia and 44-min cycling in acute normobaric severe hypoxia (3000 m). Participants were eight international level swimmers (5 females and 3 males; 17-24 years old; 173.5 ± 5.5 cm; 64.4 ± 5.3 kg) with a training volume of 80 km per week. The single-breath method was used to measure the changes in DLCO and functional gas exchange parameters. No changes in DLCO after a 14-day altitude training camp at 1850 m were detected but a decrease in alveolar volume (VA; 7.13 ± 1.61 vs. 6.50 ± 1.59 L; p = 0.005; d = 0.396) and an increase in the transfer coefficient of the lung for carbon monoxide (KCO; 6.23 ± 1.03 vs. 6.83 ± 1.31 mL·min-1·mmHg-1·L-1; p = 0.038; d = 0.509) after the altitude camp were observed. During the acute hypoxia combined session, there were no changes in DLCO after swimming training at 1850 m, but there was a decrease in DLCO after cycling at a simulated altitude of 3000 m (40.6 ± 10.8 vs. 36.8 ± 11.2 mL·min-1·mmHg-1; p = 0.044; d = 0.341). A training camp at moderate altitude did not alter pulmonary diffusing capacity in elite swimmers, although a cycling session at a higher simulated altitude caused a certain degree of impairment of the alveolar-capillary gas exchange.

Calorie Restriction Improves Physical Performance and Modulates the Antioxidant and Inflammatory Responses to Acute Exercise.

Our aim was to characterize the effects of calorie restriction on the anthropometric characteristics and physical performance of sportsmen and to evaluate the effects of calorie restriction and acute exercise on mitochondria energetics, oxidative stress, and inflammation. Twenty volunteer taekwondo practitioners undertook a calorie restriction of 30-40% on three alternate days a week for one month. Eleven volunteer sportsmen participated as controls. Both groups performed an energy efficiency test to evaluate physical performance, and samples were taken before and after exercise. The total weight of participants significantly decreased (5.9%) after calorie restriction, while the efficiency of work and the contributions of fat to obtain energy were enhanced by calorie restriction. No significant differences induced by acute exercise were observed in individual non-esterified fatty acid percentage or oxidative stress markers. Calorie restriction downregulated the basal gene expression of nitric oxide synthase, antioxidant enzymes, mitochondrial uncoupling proteins, and repairing stress proteins, but it enhanced the expression of sirtuins in peripheral blood mononuclear cells. In conclusion, one month of calorie restriction decreases body weight and increases physical performance, enhancing energy efficiency, moderating the antioxidant and inflammatory basal gene expression, and influencing its response to acute exercise.

Calorie restriction regime enhances physical performance of trained athletes.

BACKGROUND: Caloric restriction induces mitochondrial biogenesis and improves physical fitness in rodents. We aimed to provide evidence of how caloric restriction affects the body composition and physical performance of trained athletes and to evaluate the possible impact of an every-other-day feeding diet on nutritional deficiencies of micronutrients and essential fatty acids. METHODS: The study was performed with 12 healthy male athletes by carrying out a 33% caloric restriction with respect to their usual diet. Athletes performed a maximal exercise stress test both before and after the caloric restriction period. Blood samples were taken before and after the caloric restriction at basal conditions and 30 min post-exercise. Although energy intake was reduced by about 33%, the contribution of carbohydrates, proteins, and lipids to total energy intake during the caloric restriction was similar to the original diet. RESULTS: The caloric restriction reduced the daily specific micronutrient intake to values lower than 90% of recommended dietary allowances. No effects were observed in blood parameters related to iron metabolism and tissue damage, glucose levels, lipid profiles, or erythrocyte fatty acid composition. In addition, oxidative damage markers decreased after the nutritional intervention. The caloric restriction intervention significantly reduced body weight and trunk, arm, and leg weights; it also caused a decrease in fat and lean body mass, the energy expenditure rate when performing a maximal exercise stress test, and the energy cost to run one meter at various exercise intensities. Furthermore, the intervention ameliorated the onset of the anaerobic phase of exercise. CONCLUSION: A caloric restriction improves athletes' performance and energy efficiency, but reduces the daily intake of micronutrients; so, when caloric restriction programs are implemented micronutrient supplementation should be considered. TRIAL REGISTRATION: The project was registered at ClinicalTrials.gov (NCT02533479).

Erythrocytes and Skeletal Muscle Unsaturated and Omega-6 Fatty Acids Are Positively Correlated after Caloric Restriction and Exercise.

BACKGROUND: Nutritional intervention studies with fatty acid (FA) supplements assess the efficacy of the intervention by measuring the changes in erythrocyte membrane lipid profiles reflected in tissue composition changes. The aim was to determine the effects of caloric restriction (CR) on erythrocytes lipid composition and to compare and correlate these changes with skeletal muscle acid profiles after CR. METHODS: Erythrocytes were obtained from 11 healthy men before and after 4 weeks of 33% CR in post-exercise conditions; muscle biopsies were obtained from the same athletes after 4 weeks of 33% CR in post-exercise conditions. Samples were used for FA determination by chromatography. RESULTS: CR significantly modified erythrocyte FAs composition. Skeletal muscle FA profile was significantly different from that for the erythrocytes. The erythrocyte FA profile was more saturated (52.1 ± 1.5% and 32.8 ± 0.9%, respectively) and less monounsaturated (21.0 ± 0.8% and 39.0 ± 2.0%, respectively) than the skeletal muscle FA profile and similarly polyunsaturated. CONCLUSIONS: CR modifies erythrocyte lipid composition, mainly omega-6 FAs. Erythrocyte monounsaturated, polyunsaturated and omega-6 FAs, but not the saturated and omega-3 FAs, were significantly positively correlated with skeletal muscle FAs. There is a discordance between saturated and omega-3 FAs from erythrocyte and from muscle, but monounsaturated, polyunsaturated and omega-6 fatty acids are positively correlated.

Erythrocyte Omega-3 Fatty Acid Content in Elite Athletes in Response to Omega-3 Supplementation: A Dose-Response Pilot Study.

INTRODUCTION: Supplementation of Omega-3 fatty acids (n-3FA) in athletes is related to the anti-inflammatory and/or antioxidant effect and consequently its action on all the processes of tissue restoration and adaptation to physical stress. OBJECTIVE: Evaluate the Omega-3 Index (O3Ix) response, in red blood cells, to supplemental EPA + DHA intake in the form of high purity and stable composition gums (G), in elite summer athletes. METHOD: Twenty-four summer sport athletes of both sexes, pertaining to the Olympic Training Center in Spain, were randomized to two groups (2G = 760 or 3G = 1140 mg of n-3 FA in Omegafort OKids, Ferrer Intl.) for 4 months. Five athletes and four training staff volunteers were control group. RESULTS: The O3Ix was lower than 8% in 93.1% of all the athletes. The supplementation worked in a dose-dependent manner: 144% for the 3G dose and 135% for the 2G, both p < 0.001, with a 3% significant decrease of Omega-6 FAs. No changes were observed for the control group. CONCLUSIONS: Supplementation with n-3FA increases the content of EPA DHA in the red blood cells at 4 months in a dose-dependent manner. Athletes with lower basal O3Ix were more prone to increment their levels. The study is registered with Protocol Registration and Results System (ClinicalTrials.gov) number NCT02610270.

Características antropométricas, composición corporal y somatotipo por deportes. Datos de referencia del CAR de San Cugat, 1989-2013 / Anthropometric characteristics, body composition and somatotype by sport. Reference data from a high performance centre in San Cugat, 1989-2013

Las técnicas antropométricas, administradas con el rigor que corresponde, constituyen un método repetitivo, sensible y discriminante para estimar los cambios en la composición corporal de los deportistas y son ampliamente utilizadas en al ámbito de la Medicina del Deporte. A partir de las medidas antropométricas adquiridas en el seguimiento de los deportistas del CAR de Sant Cugat desde 1989 hasta la fecha, se han elaborado unas referencias, que son representativas del nivel nacional de los deportes examinados y que corresponden a los métodos de Yuhasz, Faulkner y Drinkwater, el somatotipo de Heath-Carter y el sumatorio de 6 pliegues, con el objeto de ofrecer una ayuda y orientación a los profesionales que utilicen la cineantropometría

Anthropometric techniques, when thoroughly administered, are repetitive, discriminant and sensitive methods to study changes in the body composition of athletes. This is the reason why these techniques are widely used in Sports Medicine. In this article, a summary is presented on the anthropometric analyses performed in the High Performance Centre (CAR) of Sant Cugat, Barcelona, during the last 24 years. Using all the data, a set of references tables have been obtained based on Yuhasz, Faulkner and Drinkwater anthropometric methods, Heath-Carter somatotyping, and the sum of 6 skinfolds. These tables may be used as a guide for clinicians familiar with these techniques, being representative of the national level of the sports studied

Dietary nucleotide improves markers of immune response to strenuous exercise under a cold environment.

BACKGROUND: Strenuous exercise has been classically associated to immune-suppression and consequently to an increased risk of infections, especially at the upper respiratory tract. The administration of dietary nucleotides has been demonstrated useful to maintain the immune function in situations of stress and thus could be an appropriate strategy to counteract the decline of the immune function associated to strenuous exercise. The aim of the present study was to asses the impact of a specific nucleotide formulation (Inmunactive®) on the markers of immune function of athletes after a heavy exercise bout under cold conditions. METHODS: Twenty elite male taekwondo athletes were randomly divided into two groups of 10 subjects that were supplemented with placebo (P) or Inmunactive (I) at 480 mg/day during 30 days. At baseline (day 0) and after 4 wk of supplementation (day 30) each subject undertook an exhaustion exercise test using a cycloergometer. Skin temperature, core temperature, heart rate, lactate concentration and rating of perceived exertion (RPE) were recorded during the test. Blood and saliva samples were obtained before and after each exercise test for determination of blood cell concentrations, PHA-stimulated lymphocyte proliferation (PHA-LP) and salivary immunoglobulin A (SIgA). RESULTS: Exercise tests induced neutrophilia and reduction in lymphocyte blood counts on day 0 and on day 30 in both groups. However, the I group exhibited a faster recovery from the lymphopenic response than the P group, so that lymphocyte levels were higher after 150 min (P < 0.0028). Furthermore, the lymphoproliferative response was modulated by nucleotide supplementation, since it was higher in the I group on day 30 despite an almost significant (P < 0.06) exercise-evoked decrease at baseline. CONCLUSIONS: These findings suggest that supplementation with a nucleotide-based product for 4 weeks could counteract the impairment of immune function after heavy exercise.