High-Dose Probiotic Supplementation Containing Lactobacillus casei for 7 Days Does Not Enhance Salivary Antimicrobial Protein Responses to Exertional Heat Stress Compared With Placebo.

The study aimed to determine whether high-dose probiotic supplementation containing Lactobacillus casei (L. casei) for 7 consecutive days enhances salivary antimicrobial protein (S-AMP) responses to exertional-heat stress (EHS). Eight endurance-trained male volunteers (age 26 ± 6 years, nude body mass 70.2 ± 8.8 kg, height 1.75 ± 0.05 m, VO2max 59 ± 5 ml·kg-1·min-1 [M ± SD]) completed a blinded randomized and counterbalanced crossover design. Oral supplementation of the probiotic beverage (PRO; L. casei . 1011 colony-forming units·day-1) or placebo (PLA) was consumed for 7 consecutive days before 2 hr running exercise at 60% VO2max in hot ambient conditions (34.0° C and 32% RH). Body mass and unstimulated saliva and venous blood samples were collected at baseline (7 days before EHS), pre-EHS, post-EHS (1 hr, 2 hr, and 4 hr), and at 24 hr. Saliva samples were analyzed for salivary (S) IgA, α-amylase, lysozyme, and cortisol. Plasma samples were analyzed for plasma osmolality. Body mass and plasma osmolality did not differ between trials. Saliva flow rate remained relatively constant throughout the experimental design in PRO (overall M ± SD = 601 ± 284 µl/min) and PLA (557 ± 296 µl/min). PRO did not induce significant changes in resting S-AMP responses compared with PLA (p > .05). Increases in S-IgA, S-α-amylase, and S-cortisol responses, but not S-lysozyme responses, were observed after EHS (p < .05). No main effects of trial or Time x Trial interaction were observed for S-AMP and S-cortisol responses. Supplementation of a probiotic beverage containing L. casei for 7 days before EHS does not provide any further oral-respiratory mucosal immune protection, with respect to S-AMP, over PLA.

The enemy of the feet: blisters in ultraendurance runners.

BACKGROUND: Blisters are the most common dermatologic problem in ultraendurance runners. Their incidence, localization, pain scores, and risk factors in field conditions are poorly understood. METHODS: We conducted an observational field-based cohort study during the 5-day multistage 2010 and 2011 Al Andalus Ultimate Trail (219 km). Daily postrace data on blister frequency, localization, severity, and preventive measures from 50 ultramarathon runners were collected through the direct interview technique. RESULTS: After 4 days of running (182 km), blisters occurred in 76% of the participants (P < .001 versus stage 1) compared with 34% after day 1, 54% after day 2, and 72% after day 3 (P < .001 versus stage 1). Most of the blisters formed on the toes (65%) (P < .001), followed by blisters on other locations of the foot: the ball of the foot (16%), heel (14%), and sole (5%). Blisters were more painful toward the end of the race, and those on the sole and heel tended to be the most painful, although this did not reach statistical significance. Prophylactic measures studied (type and fabric of socks; application of antiperspirants, talcum powder, or lubricant to feet; and prophylactic taping) did not show any reduction in blister rates. The only predictive marker for reduced blister incidence was previous ultramarathon experience in men (r = -0.44, P < .05). CONCLUSIONS: Blisters are extremely common in multistage ultramarathon races. Race experience in male ultramarathon runners is associated with reduced blister rates.

Daily hematologic assessment during a 230-km multistage ultramarathon / Avaliação hematológica diária durante uma ultramaratona de múltiplos estágios de 230 km / Evaluación hematológica diaria durante una ultramaratón de múltiples etapas de 230 km

ABSTRACT Introduction: The popularity of ultra-endurance events is increasing worldwide. However, information about hematological parameters during repeated bouts of long-duration running, such as stages during a multi-stage ultramarathon (MSUM) is scarce. Objective: The purpose of the study was to monitor daily hematologic assessment in a 230-km multistage ultramarathon (MSUM) in hot environmental conditions. Methods: Eleven male and three female (n = 14) ultra-endurance runners entered this MSUM, which was conducted over five stages, covering a total distance of 230 km in hot ambient conditions. Peripheral blood samples were collected before and after each stage to determine leukocyte and erythrocytes parameters. Results: Multilevel modelling considering all measurement points showed an increase for whole blood leukocyte and granulocyte counts at five stages of the MSUM and for monocytes until Stage 3 of the race. For erythrocyte parameters, decreases across stages were observed in hemoglobin concentration and hematocrit responses when computing/considering all measurement points. Conclusions: The results indicate that MSUM in a hot environment leads to a greater impact on leukocyte population responses and platelet variation in the initial stages of the race. We suggest that athletes may have a decrease in immune function in the early stages of the MSUM, probably with some transient risk of infectious. Nevertheless, a physiological adaptation to physical exertion and heat mitigates these changes in the subsequent stages of MSUM. Level of Evidence III; Case-control study.

RESUMO Introdução: A popularidade dos eventos de ultra-resistência está aumentando em todo o mundo. Entretanto, faltam informações sobre os parâmetros hematológicos durante episódios repetidos de corridas de longa duração, como, por exemplo, os estágios durante uma ultramaratona de múltiplos estágios (MSUM). Objetivo: O objetivo do estudo foi monitorar a avaliação hematológica diária em uma ultramaratona de múltiplos estágios (MSUM) de 230 km sob condições climáticas quentes. Métodos: Onze corredores e três corredoras de -ultra-resistência (n = 14) participaram dessa MSUM, em cinco estágios, totalizando uma distância de 230 km sob condições climáticas quentes. As amostras de sangue periférico foram coletadas antes e após cada estágio para determinação dos parâmetros de leucócitos e eritrócitos. Resultados: O modelo multinível considerando todos os pontos de medição apresentou um aumento na contagem de leucócitos e granulócitos do sangue total nos cinco estágios da MSUM e para os monócitos até o estágio três da competição. Para os parâmetros dos eritrócitos, foram observadas reduções através dos estágios na concentração de hemoglobina e nas respostas do hematócrito ao se contabilizar/considerar todos os pontos de medição. Conclusões: Os resultados indicam que a MSUM em condições climáticas quentes exerce um maior impacto nas respostas da população de leucócitos e na variação plaquetária nos estágios iniciais da competição. Sugerimos que os atletas podem ter uma diminuição na função imune nos estágios iniciais da MSUM, provavelmente, com algum risco transitório de infecção. No entanto, uma adaptação fisiológica para o esforço físico e calor minimiza essas alterações nos estágios seguintes da MSUM. Nível de Evidência III; Estudo caso-controle.

RESUMEN Introducción: La popularidad de los eventos de ultra resistencia está aumentando en todo el mundo. Entretanto, faltan informaciones sobre los parámetros hematológicos durante episodios repetidos de carreras de larga duración, como por ejemplo, las etapas de una ultramaratón de múltiples etapas (MSUM). Objetivo: El objetivo del estudio fue monitorizar la evaluación hematológica diaria en una ultramaratón de múltiples etapas (MSUM) de 230 km bajo condiciones climáticas cálidas. Métodos: Once corredores y tres corredoras de ultra resistencia (n = 14) participaron en esa MSUM, en cinco etapas, totalizando una distancia de 230 km bajo condiciones climáticas cálidas. Las muestras de sangre periférica fueron colectadas antes y después de cada etapa para determinación de los parámetros de leucocitos y eritrocitos. Resultados: El modelo multinivel considerando todos los puntos de medición presentó un aumento en el conteo de leucocitos y granulocitos de la sangre total en las cinco etapas de la MSUM y para los monocitos hasta la etapa 3 de la competencia. Para los parámetros de eritrocitos, fueron observadas reducciones a través de las etapas en la concentración de hemoglobina y en las respuestas de hematocrito al contabilizar/considerar todos los puntos de medición. Conclusiones: Los resultados indican que la MSUM en condiciones climáticas cálidas ejerce un mayor impacto en las respuestas de la población de leucocitos y en la variación plaquetaria en las etapas iniciales de la competencia. Sugerimos que los atletas pueden tener una disminución en la función inmune en las etapas iniciales de la MSUM probablemente con algún riesgo transitorio de infección. Sin embargo, una adaptación fisiológica para el esfuerzo físico y el calor, minimiza esas alteraciones en las etapas siguientes de la MSUM. Nivel de Evidencia III; Estudio de caso-control.

Salivary antimicrobial protein responses during multistage ultramarathon competition conducted in hot environmental conditions.

Prolonged strenuous exercise is commonly reported to depress oral-respiratory immune status and increase the incidence of upper respiratory symptoms. This novel investigation aimed to determine the salivary antimicrobial responses and hydration status of ultraendurance runners (n = 23) during a 230-km multistage ultramarathon conducted in hot ambient conditions (32-40 °C). Body mass was measured and unstimulated saliva and venous blood samples were taken before and after each stage of the ultramarathon. Ad libitum fluid intake was permitted throughout each race day. Upper respiratory symptoms were monitored during and until 4 weeks after race completion. Samples were analyzed for salivary immunoglobulin A (IgA), lysozyme, α-amylase, and cortisol, as well as for plasma and saliva osmolality. Mean exercise-induced body mass loss over the 5 stages ranged from 1.3% to 2.4%. Overall mean pre- and post-stage plasma osmolality measurements in the ultraendurance runners were 279 ± 14 mOsmol·kg(-1) and 293 ± 15 mOsmol·kg(-1), respectively. Decreases in saliva flow rate (overall change 22%) and post-stage increases in saliva osmolality (36%) were observed in the ultraendurance runners during the ultramarathon. Reduced salivary IgA (32%) (p < 0.001 vs. pre-stage salivary IgA), enhanced salivary α-amylase (187%) (p < 0.001 vs. pre-stage salivary α-amylase), and no change in salivary lysozyme secretion rates were observed in the ultraendurance runners throughout the ultramarathon. Only 1 ultraendurance runner reported upper respiratory symptoms during and 1 month after competition. Observed depressions in salivary IgA secretion rates were offset by favourable increases in salivary α-amylase and unchanged lysozyme responses in the majority of runners during the competition. Ensuring euhydration throughout a multistage ultramarathon competition in the heat may play a role in protecting the upper respiratory tract.