Benefits to the host metabolism resulting from Saccharomyces boulardii (Sb) supplementation have been described; however, no study has investigated the effects of this supplementation on aerobic metabolism and performance during physical exercise. Thus, in the present study, we addressed the effects of Sb supplementation on the rate of oxygen consumption (VO2), mechanical efficiency (external work divided by VO2), and aerobic performance of rats subjected to fatiguing, incremental-speed exercise. Twenty-six male Wistar rats were randomly divided into two groups: (1) non-supplemented, in which rats received 0.1 mL of a saline solution, and (2) Sb-supplemented, in which rats received 0.1 mL of a suspension containing 8.0 log10 colony-forming units. The rats received the treatments by gavage for 10 consecutive days; they were then subjected to fatiguing treadmill running. Sb supplementation did not change the VO2 values or mechanical efficiency during submaximal exercise intensities. In contrast, at fatigue, VO2MAX was increased by 12.7% in supplemented rats compared with controls (p = 0.01). Moreover, Sb improved aerobic performance, as evidenced by a 12.4% increase in maximal running speed attained by the supplemented rats (p < 0.05). We conclude that Sb supplementation for 10 days increases VO2MAX and aerobic performance in rats.

Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology.

Physical exercise triggers coordinated physiological responses to meet the augmented metabolic demand of contracting muscles. To provide adequate responses, the brain must receive sensory information about the physiological status of peripheral tissues and organs, such as changes in osmolality, temperature and pH. Most of the receptors involved in these afferent pathways express ion channels, including transient receptor potential (TRP) channels, which are usually activated by more than one type of stimulus and are therefore considered polymodal receptors. Among these TRP channels, the TRPV1 channel (transient receptor potential vanilloid type 1 or capsaicin receptor) has well-documented functions in the modulation of pain sensation and thermoregulatory responses. However, the TRPV1 channel is also expressed in non-neural tissues, suggesting that this channel may perform a broad range of functions. In this review, we first present a brief overview of the available tools for studying the physiological roles of the TRPV1 channel. Then, we present the relationship between the TRPV1 channel and spontaneous locomotor activity, physical performance, and modulation of several physiological responses, including water and electrolyte balance, muscle hypertrophy, and metabolic, cardiovascular, gastrointestinal, and inflammatory responses. Altogether, the data presented herein indicate that the TPRV1 channel modulates many physiological functions other than nociception and thermoregulation. In addition, these data open new possibilities for investigating the role of this channel in the acute effects induced by a single bout of physical exercise and in the chronic effects induced by physical training.

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-The purpose of the present study was to analyze the energy expenditure and heart rate (HR), expressed as mean and maximal heart rate (HR max ), along matches of an official soccer competition. Methods: Eighteen under-20 year old (U-20) soccer players from a first-division Brazilian soccer team were evaluated during 15 matches. The relationship between HR and oxygen uptake (HR/VO 2 relationship) was established, and a linear regression equation was developed for each individual player participating in the study. This equation was then used to determine the oxygen uptake and the corresponding energy expenditure based on the HR values measured during the games. The HR was recorded at 5-second intervals, which were clustered in phases of 15 minutes (0-15 min, 15-30 min e 30-45 min) for each half time (first half [FH] and second half [SH]). Results: The players' oxygen uptake was 308.3 ± 11.9 LO 2 /game and the energy expenditure was 17.3±1.3 Kcal.min -1 and 1,542.9±125.1 Kcal/game. The results showed that there were significant differences between the HR and HR max identified in the first half (FH 15-30 min) compared to the second half (SH 0-15 min and SH 30-45 min), and at FH 30-45 min compared to SH 0-15 min (p<0.05). Conclusions: We concluded that soccer should be considered as an extremely arduous activity for U-20 players due to the high energy expenditure during the matches of an official championship. We also concluded that, during soccer games with young players, FH 15-30 min could be considered the most intense phase, because the highest values of HR and HR max usually occur at this phase. Key words: Correlation; Energy expenditure; Intermittent. Resumo -O objetivo do presente estudo foi a análise do gasto energético e da frequência cardíaca (HR), expressa pela média e pela frequência cardíaca máxima (FC max ), durante jogos de uma competição oficial de futebol. Foram avaliados, durante 15 jogos, dezoito jogadores de futebol da categoria abaixo de 20 anos de idade 420Energy demand and heart rate in soccer Coelho et al.