Temperature variation affects most biological parameters from the molecular level to community structure and dynamics. Current studies on thermal biology assess how populations vary in response to environmental temperature, which can help determine how populations differentially respond to climate change. To date, temperature fluctuation effects on endothermic poikilotherms such as the common eastern bumblebee (Bombus impatiens) are unknown even though bumblebees are the most important natural pollinators in North America. A cold-acclimation experiment with B. impatiens colonies revealed individuals acclimated to 5°C or 10°C at night did not differ in resting metabolic rate, flight metabolic rate, wingbeat frequency, or morphological measurements, compared to the control group. Moreover, an infrared camera showed that all colonies maintained maximum nest temperature consistently above 36.8°C. A latitudinal sampling of flight metabolic rate and morphological measurements of B. impatiens from four locations spanning Ontario (N 45°; W 75°) to North Carolina (N 34°; W 77°) indicated no latitudinal trend in the measured variables. This study shows that bumblebees are well equipped to face a wide range of environmental temperatures, both in the short term and long term, and can use a combination of behavioural and physiological mechanisms to regulate body and nest temperatures. These results are reassuring on the direct effects of climate change on bumblebee ecology, but further studies on the indirect effect of temperature variation on North American bumblebees are required to predict future ecosystem dynamics.

abstract: Though it is a widespread adaptation in humans and many other animals, parental care comes in a variety of forms and its subtle physiological costs, benefits, and tradeoffs related to offspring are often unknown. Thus, I studied the hydric, respiratory, thermal, and fitness dynamics of maternal egg-brooding behavior in Children's pythons (Antaresia childreni). I demonstrated that tight coiling detrimentally creates a hypoxic developmental environment that is alleviated by periodic postural adjustments. Alternatively, maternal postural adjustments detrimentally elevate rates of egg water loss relative to tight coiling. Despite ventilating postural adjustments, the developmental environment becomes increasingly hypoxic near the end of incubation, which reduces embryonic metabolism. I further demonstrated that brooding-induced hypoxia detrimentally affects offspring size, performance, locomotion, and behavior. Thus, parental care in A. childreni comes at a cost to offspring due to intra-offspring tradeoffs (i.e., those that reflect competing offspring needs, such as water balance and respiration). Next, I showed that, despite being unable to intrinsically produce body heat, A. childreni adjust egg-brooding behavior in response to shifts in nest temperature, which enhances egg temperature (e.g., reduced tight coiling during nest warming facilitated beneficial heat transfer to eggs). Last, I demonstrated that A. childreni adaptively adjust their egg-brooding behaviors due to an interaction between nest temperature and humidity. Specifically, females' behavioral response to nest warming was eliminated during low nest humidity. In combination with other studies, these results show that female pythons sense environmental temperature and humidity and utilize this information at multiple time points (i.e., during gravidity [egg bearing], at oviposition [egg laying], and during egg brooding) to enhance the developmental environment of their offspring. This research demonstrates that maternal behaviors that are simple and subtle, yet easily quantifiable, can balance several critical developmental variables (i.e., thermoregulation, water balance, and respiration). / Dissertation/Thesis / Ph.D. Biology 2011

Four studies were performed to evaluate the independent influence of core temperature and heat acclimation on sweating responses when exercise is fixed for a given evaporative heat balance requirement (Ereq) during compensable and uncompensable heat stress. By using circadian rhythm to modulate absolute core temperature, study 1 investigated whether absolute core temperature altered the steady-state sweat rate during compensable heat stress at a fixed Ereq. Study 2 compared the influence of partial and complete heat acclimation on core temperature and sweating responses between a compensable and uncompensable heat stress condition. Study 3 quantified how maximum skin wettedness is altered with partial or complete heat acclimation. Study 4 determined whether aerobic fitness (i.e. maximum rate of oxygen consumption; VO2max) per se independently alters the sweating and core temperature responses to uncompensable heat stress or if the frequent bouts of exercise-induced heat stress that accompany aerobic training are required to augment thermoregulatory capacity. Study 1 demonstrated that when absolute core temperature is different between AM and PM by ~0.2°C, steady-state sweat rates were the same for a fixed Ereq. Only when a different level of Ereq was attained, were differences in steady-state sweating observed. Moreover, steady-state sweat rates were similar despite differences in skin and core temperature when exercise intensity was matched to elicit a fixed Ereq in two different ambient temperatures (23°C and 33°C). In study 2, neither partial nor complete heat acclimation altered the core temperature response to compensable heat stress despite a marginally greater sweat rate compared to an unacclimated state. However, the sudomotor adaptations associated with heat acclimation were evident during uncompensable heat stress and mitigated the rise in core temperature during 60 minutes of exercise compared to an unacclimated state. Study 3 determined that the biophysical parameter that defines the upper limit for evaporative heat loss, that is the maximum skin wettedness achievable, increased following partial (0.84±0.08) and complete heat acclimation (0.95±0.05) compared to unacclimated (0.72±0.06) which directly explains the reduced change in core temperature reported in study 2 during uncompensable heat stress. Lastly, study 4 demonstrated that VO2max per se does not alter the sudomotor responses to uncompensable heat stress. Rather, it is the repetitive exercise-induced heat stress experienced during aerobic training that induces a partial heat acclimation thereby mitigating the rise in core temperature during uncompensable heat stress. Taken together, when exercise is prescribed in a compensable environment, the steady-state sweat rate observed will be primarily determined by Ereq independent of absolute core temperature, while heat acclimation will slightly increase the sweat rate despite providing no additional reduction in the change in core temperature. However, progressive heat acclimation increases the upper limit of compensability via a greater maximum skin wettedness thereby mitigating the rise in core temperature during uncompensable heat stress.

Following on from Rio de Janeiro 2016, the Tokyo 2020 Paralympic Games will present a unique challenge for athletes, needing to prepare and adapt to the potential challenging environmental conditions of 20-27°C and ~73% relative humidity. It is well known that during exercise in hot and/or humid climates, able-bodied athletes experience an increase in thermal strain and a reduction in performance compared to cooler/drier conditions. Yet these conditions prove even more problematic for athletes, who as a consequence of their impairment have a dysfunctional thermoregulatory system, such as athletes with a spinal cord injury (SCI). To date, the thermoregulatory responses of athletes with an SCI have been an under-studied area of research. To gain a greater understanding of how heat balance is altered in individuals with an SCI and the thermoregulatory consequences as a result, studies need to first be conducted at rest, removing the additional metabolic heat production from exercise. Although a large majority of athletes with an SCI compete indoors in wheelchair court sports (e.g. wheelchair basketball and rugby), exercising even in these climate-controlled environments has been shown to place these athletes under considerable thermal strain. In light of this, it is remarkable that existing research on the thermoregulatory responses of athletes with an SCI during exercise is scarce, especially studies encompassing real-world sporting environments. Athletes with high level lesions (tetraplegia, TP) are a particularly under-studied population group shown to have a greater thermoregulatory impairment than individuals with low level lesions (paraplegia, PA) during continuous exercise. Thus the aim of this thesis was to investigate the thermoregulatory responses of athletes with an SCI at rest and during real-world sporting scenarios, with specific focus on athletes with TP. Study 1 aimed to determine how evaporative heat loss is altered, as a result of an SCI, compared to the able-bodied (AB), and the effect lesion level has on this response. The results provide evidence that in individuals with TP, even at rest, evaporative heat loss is not large enough to balance the heat load, when evaporation is the primary source of heat dissipation. Even though in individuals with PA Tgi increased by a smaller magnitude and they possessed a greater sweating capacity than individuals with TP, at ambient temperatures above Tsk latent heat loss is insufficient to attain heat balance, compared to the AB. To investigate the thermoregulatory responses of athletes with an SCI during real-world sporting scenarios Study 2 examined athletes with TP compared to athletes with PA during 60 min of intermittent sprint wheelchair exercise on a wheelchair ergometer. The study was conducted in conditions representative of an indoor playing environment for wheelchair rugby and basketball (~21°C, 40% relative humidity). Results demonstrated that, despite similar external work, athletes with TP were under greater thermal strain than athletes with PA. Study 3 s novel approach investigated both physiological responses and activity profiles of wheelchair rugby players during competitive match play. Despite players with TP covering 17% less distance and pushing on average 10% slower, they were under a greater amount of thermal strain than players with non-spinal related physical impairments (NON-SCI). Furthermore, this study demonstrated that players with TP that had a larger body mass, larger lean mass, covered a greater relative distance and/or were a higher point player had a greater end Tgi. These data provide an insight for coaches and support staff regarding which players may need greater attention in regards to cooling strategies or breaks in play. The effectiveness of cooling practices currently employed by athletes with TP has not been previously investigated. Study 4 determined the effectiveness of pre-cooling, using an ice vest alone and in combination with water sprays between quarters, at attenuating thermal strain in athletes with TP. Using the activity profile data from Study 3, an intermittent sprint protocol, conducted on a wheelchair ergometer, was used to represent a wheelchair rugby match. The combination of cooling methods lowered Tgi and Tsk to a greater extent than pre-cooling only, despite neither cooling condition having a positive or negative effect on performance. Unexpectedly, the pre-cooling only condition lowered Tgi, compared to no cooling, throughout the subsequent exercise protocol, even though the reduction in Tsk was not long lasting. This thesis provides comprehensive evidence that athletes with TP experience heightened thermal strain during both rest and real-world sporting scenarios compared to the AB, athletes with PA, and within the sport of wheelchair rugby. Athletes with TP should employ practices, such as appropriate cooling methods or alter playing tactics to reduce thermal strain and the likelihood of attaining a heat related injury.

Made available in DSpace on 2016-08-15T20:30:55Z (GMT). No. of bitstreams: 1 LeonardoLMC_DISSERT.pdf: 1176741 bytes, checksum: cae29c28ee7539a3660b0db230755381 (MD5) Previous issue date: 2010-08-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / We evaluated the Thermoregulation of the scrotum associated with quality semen of goats grazed in the meteorological conditions of the semi-arid. 10 goats were used. There were 5 observations, with four days of interval. Five groups were formed, each group was collected in different hours (8am, 10am, 12pm, 2pm and 4pm). The skin surface body temperatures (SSBT) and the scrotum (ST), respiratory rate and rectal temperature were recorded. Heat loss by cutaneous evaporation was measured from the H2O/CO2 analyzer, in the body was used a vented cap and in the scrotum was developed a ventilated capsule adapted for that region. The area of scrotum was determined through analysis of regression. Semen was collected via an artificial vagina and evaluated macro-and microscopically. Irradiance, wind speed, air, wet bulb and black globe temperatures were recorded. The Statistical analysis was based on the method of least squares. For analysis of quality of the semen it was used a 5x5 Latin square design. The SSBT 34.5 ±0.92ºC and ST was 33.5 ±0.36ºC, showing a difference of 1ºC between those regions. The latent heat loss was 57.3 ±18.0 W.m-2 for body surface and 49.4 ±15.0 Wm-2 to the scrotum. Semen samples were considered of good quality at all times and days of collection. The conclusion was that the difference between the surface temperatures derive from a combination of mechanisms which involve thermoregulation of the scrotum, and the animals can be utilized for breeding at any time of the day. / Avaliou-se a Termorregulação da bolsa escrotal associada à qualidade do sêmen de caprinos manejados nas condições meteorológicas do semiárido. Foram utilizados 10 caprinos. Foram realizadas 5 observações, com 4 dias de intervalo entre elas. Formou-se 5 grupos, onde cada grupo era coletado em horas distintas (8, 10, 12, 14 e 16h). As temperaturas da superfície cutânea do corpo (TSPSC) e da bolsa escrotal (TSPBE) e retal e freqüência respiratória foram registradas. A perda de calor por evaporação cutânea foi mensurada a partir do analisador de H2O/CO2, no corpo foi utilizada uma cápsula ventilada e na bolsa escrotal foi desenvolvida uma cápsula ventilada adaptada para esta região. A área da bolsa escrotal foi determinada através de análise de regressão. O sêmen foi colhido através de uma vagina artificial e avaliado macro e microscopicamente. Foram registradas a irradiância, velocidade do vento e temperaturas do ar, do bulbo úmido e do globo negro. A análise estatística foi baseada no método dos quadrados mínimos. Para análise da qualidade do sêmen foi utilizado um delineamento quadrado latino 5x5. A TSPSC 34,5 ±0,92ºC e TSPBE foi 33,5 ±0,36ºC, demonstrando diferença de 1 ºC entre estas regiões. A perda de calor latente foi de 57,3 ±18,0W.m-2 para a superfície do corpo e de 49,4 ±15,0 W.m-2 para a bolsa escrotal. O semên foi considerado de boa qualidade em todos os horários e dias de coleta. Cocluiu-se que a diferença ente as temperaturas de superfícies deriva de uma associação de mecanismos que envolve a termorregulação da bolsa escrotal e que os animais podem ser utlizados para reprodução a qualquer hora do dia.

Estratégias de aclimatização ao calor e recomendações de segurança à saúde para crianças e jovens que se exercitam no calor são enfatizadas na literatura, devido principalmente à limitação da perda de calor pela sudorese, em comparação aos adultos; e acredita-se que, nos meninos obesos, essa resposta possa ser mais prejudicada. Aspectos relacionados à termorregulação e à sudorese, além de recomendações para a prática prolongada de exercícios no calor, em crianças e jovens, incluindo obesos, foram revisados na literatura; e um estudo experimental foi realizado. Objetivo: Comparar a temperatura retal (Tretal), a sudorese e a sensação subjetiva de calor (SSC) entre meninos púberes obesos e não-obesos que pedalam em uma similar intensidade relativa de esforço e na mesma condição ambiental. Métodos: No estudo experimental, meninos púberes fisicamente ativos foram alocados em dois grupos (obesos, n = 17; e não-obesos, n = 16). Ambos pedalaram dentro de uma câmara ambiental (35°C, 40-45% UR) por 30 min, a 50-60% do VO2pico; e, após 10 min de repouso, pedalaram até a exaustão (90% do VO2pico). A Tretal, a frequência cardíaca (FC), a sudorese, a taxa de percepção de esforço (TPE) e a SSC foram avaliadas durante os 30 min de pedalada; e a Tretal e a FC, durante a pedalada mais intensa. Resultados: O aumento da Tretal e da FC, assim como as respostas da sudorese foram similares entre os grupos, durante os 30 min de pedalada. A TPE foi maior nos obesos dos 25 aos 30 min de pedalada; e a SSC, durante os 30 min de pedalada. Obesos pedalaram intensamente (90% do VO2pico) por menos tempo que os não-obesos, e a ΔTretal foi maior nos não-obesos. Conclusão: A prescrição do exercício nas condições do protocolo seguido no presente estudo pode ser fisiologicamente segura para meninos púberes obesos fisicamente ativos e aclimatizados ao calor; mas não generalizadas a meninos obesos sedentários e/ou não-aclimatizados ao calor. O maior desconforto térmico dos meninos obesos ressalta a importância das mensurações subjetivas no auxílio à escolha da modalidade de exercício mais adequada para os meses do verão, o que pode prevenir riscos de doenças relacionadas ao calor. / Strategies of acclimatization to the heat and health safety recommendations for children and adolescents exercising in the heat are emphasized in the literature, particularly due to the limitation of heat loss through sweating as compared to adults; moreover, it is thought that this response may be impaired in obese children. Aspects relevant to thermoregulation and sweating, as well as recommendations for the prolonged practice of exercises in the heat by children and adolescents, including obese ones, were reviewed in the literature, and an experimental trial was performed. Aim: To compare the rectal temperature (Trect), sweat rate, and subjective sensation of heat (SSH) between obese and non-obese pubertal boys who cycled at a similar relative effort intensity and in the same environmental conditions. Methods: In the experimental trial, physically active pubertal boys were placed in two groups (obese, n = 17; and non-obese, n = 16). Both cycled inside an environmental chamber (35°C, 40-45% RH) for 30 min. at 50-60% VO2peak, rested for 10 min., and then cycled to exhaustion (90% VO2peak). Trect, heart rate (HR), sweat rate, rate of perceived exertion (RPE) and subjective sensation of heat (SSH) were assessed during the 30 min. of cycling; and Trect and HR during the most intense cycling. Results: The increase in Trect and HR as well as the sweating responses were similar between the groups during the 30-minute cycling. The RPE was greater in the obese at 25-30 minutes of cycling; and the SSH throughout the 30 minutes. The obese cycled intensely (90% VO2peak) for shorter than the non-obese, and Trect was greater in the non-obese. Conclusion: The prescription of exercise in the protocol conditions used in the present study may be physiologically safe for physically active, heat acclimated obese pubertal boys, but it cannot be generalized to obese boys who are sedentary and/or non-acclimated to the heat. The greatest thermal discomfort of obese boys highlights the importance of including subjective assessments in selecting the most suitable exercise modality for the summer months, which may avoid risks and prevent heat-related disorders.

La prévalence de l'obésité et le sédentarisme chez les adolescents augmentate de manière significative dans le monde entier. La chaleur de l'environnement est une préoccupation supplémentaire au moment de recommander la pratique du sport chez les adolescents obèses et sédentaires. Les risques liés á l’augmentation de la température centrale du corps sont á considérer. L’augmentation de température est un facteur aggravant qui augmente de la perception de l'effort (IPE), l’irritabilité, et modifie les sensations liées au confort thermique. Il existe peu d'études ayant evalué les réponses de thermorégulation et la perception des filles pratiquant l'exercice dans la chaleur, en particulier chez les filles obèses. Par conséquent, il est utile d’apporter plus de précisions sur l'impact de l'obésité associée ou non à un mode de vie sédentaire pendant les activités sportives dans la chaleur. Le but de cette étude était de déterminer et comparer la thermorégulation et les réponses perceptives des filles pubères obèses et de poids normal avec un profil de forme cardiorespiratoire élevé (fit) et faible (unfit) avant, pendant et après deux séances d'entraînement dans la chaleur. Ceci a été réalisé au cours d’ une étude transversale dans laquelle 34 filles: 21 obèses (12 fit et 9 unfit) et 13 de poids normal (5 fit et 8 unfit) ont pédalé pendant 50 minutes sur un ergomètre à 36oC et 40% HR à l'intérieur une chambre environnementale. Deux séances d'exercice avec des intensités d’efforts différentes ont été réalisées. Dans la première session l'objectif a été fixé á 45% du VO2pic (Sèance % VO2pic) et dans la seconde á 4,5 W.kg-1 (Sèance PCM). Pendant les séances d'exercice, la température rectale (Tre), la température de la peau (IPEau), la fréquence cardiaque (FC), IPE, l’ irritabilité, et les sensations thermique et de confort thermique ont été recueillies. Aucune différence n'a été identifiée entre les groupes tout au long de la séance d'exercice et de récupération pour les variables de thermorégulation, perception et transpiration dans les deux conditions d’effort testées. Les résultats de ce travail montrent que indépendamment de la capacité cardiorespiratoire, dans les conditions d'exercice et le stress thermique de 36oC et 40% d'humidité relative, les filles pubères obèses ou non ont des réponses de thermorégulation et perception similaires lors de l'exercice effectué au cours d’ un ergocycle réalisé á températures élevées. / A prevalência da obesidade e do sedentarismo entre os adolescentes vem aumentando mundialmente de forma significativa. Acredita-se que o calor ambiental é uma preocupação adicional ao recomendar a prática esportiva em adolescentes obesos e sedentários, pois além dos riscos de aumento da temperatura corporal central, representa um agravante no aumento da percepção ao esforço (IPE), da irritabilidade, da sensação térmica e do conforto térmico. Ainda são poucos os estudos que avaliaram respostas termorregulatórias e perceptivas de meninas que realizaram exercícios no calor, especialmente de meninas obesas. Portanto, são necessários mais esclarecimentos das repercussões da obesidade combinada ou não com o sedentarismo durante a prática de atividades esportivas no calor. O objetivo deste estudo foi determinar e comparar as respostas termorregulatórias e perceptivas de meninas púberes obesas e eutróficas com alta (fit) e baixa (unfit) aptidão cardiorrespiratória antes, durante e após duas sessões de exercício no calor. Trata-se de um estudo de caráter transversal em que 34 meninas: 21 obesas (12 fit e 9 unfit) e 13 eutróficas (5 fit e 8 unfit) pedalaram durante 50 minutos em cicloergômetro no calor (36oC e 40% de umidade relativa do ar) dentro de uma câmara ambiental. Foram realizadas duas sessões de exercício com metas de intensidade diferentes. Na primeira sessão, fixou-se a meta de intensidade em 45% do pico de Volume de O2 (Sessão %VO2pico) e na segunda, em 4,5 W.kg-1 (Sessão PCM). Durante as sessões de exercício, foram coletadas temperatura retal (Tre), temperatura de pele (Tpele), frequência cardíaca (FC), IPE, irritabilidade, sensação térmica e conforto térmico. Não foram identificadas diferenças entre os grupos ao longo da sessão de exercício e recuperação para as variáveis termorregulatórias, perceptivas e de sudorese quando meninas obesas e eutróficas fit e unfit pedalaram em cicloergômetro a 45% do VO2pico ou a 4,5 W.kg-1 durante 50 minutos em câmara ambiental. Assim, conclui-se que independente do estado nutricional ou aptidão cardiorrespiratória, sob as condições de exercício e estresse térmico de 36oC e 40% UR, meninas púberes apresentam respostas termorregulatórias e perceptivas semelhantes quando submetidas a uma sessão de exercício em cicloergômetro no calor. / Obesity prevalence and sedentary behavior among teenagers is increasing significantly worldwide. It is believed that the heat stress is an additional concern when recommending the practice of sports to obese and sedentary adolescents. In addition, the risks of increasing core body temperature is an aggravating factor to the increase in the perceived exertion (RPE) irritability, thermal sensation and thermal comfort. Few studies have evaluated thermoregulatory and perceptual responses in girls who underwent exercise in the heat, especially in obese girls. Therefore, further understanding of the impact of obesity combined or not with sedentary behavior during sport activities under heat stress is still required. The aim of this study was to determine and to compare the thermoregulatory and perceptual responses of obese and eutrophic pubescent girls with high (fit) and low (unfit) cardiorespiratory capacity, before,during and after two workouts under heat stress. This is a transversal study including 34 girls, in which 21 obese (12 fit and 9 unfit) and 13 eutrophic (5 fit and 8 unfit) cycled for 50 min on a cycle ergometer under heat stress (36oC and 40% RH), inside an environmental chamber. Two exercise sessions with different intensity targets were performed. In the first session, the intensity target was set at 45% of the VO2peak (% VO2peak Session), and the second was set at 4.5 W.kg-1 (MHP Session). During the exercise sessions, rectal temperature (Tre), skin temperature (Tskin), heart rate (HR) RPE, irritability, thermal sensation, and thermal comfort were collected. No differences were detected between groups throughout the exercise and during the recovery session for thermoregulatory, perceptive and sweat variables when obese and eutrophic fit and unfit girls exercised on a cycle ergometer at 45% of VO2peak or 4.5 W.kg-1 for 50 min in an environmental chamber. Therefore, it is concluded that, regardless the nutritional status or cardiorespiratory capacity, under the conditions of exercise and heat stress of 36oC and 40% RH, pubescent girls have similar thermoregulatory and perceptual responses when exercising on a cycle ergometer in the heat.

Introdução: O exercício é conhecido como uma das ferramentas mais poderosas para prevenir e controlar a obesidade. No entanto, as razões pelas quais indivíduos obesos parecem ser menos dispostos do que aqueles com peso normal para participar e aderir a programas de exercícios são ainda desconhecidas. Uma das hipóteses é que as altas taxas de abandono tipicamente encontradas entre os adolescentes obesos pode ser devido ao tipo de exercício prescrito, e/ou uma capacidade termorregulatória comprometida. A interação entre exercício e excesso de peso pode alterar algumas variáveis, tais como, temperatura corporal, percepção de esforço, conforto térmico e irritabilidade, especialmente se os programas de exercícios são realizados em ambientes com altas temperaturas. Objetivo: Este estudo investigou as respostas fisiológicas e perceptivas em adolescentes obesas em sessões de exercícios concorrente (EC) e de exercícios aeróbico (EA), em duas condições ambientais: calor (C) e termoneutro (Tn). Métodos: Doze meninas púberes obesas (12,7±0,6 anos, 49,9± 3,0% de gordura) fisicamente ativas e aclimatizadas ao calor foram designadas para participar de quatro sessões de testes (EA e EC onde no EA foi de 40 minutos e consistia de cicloergômetro (60-70% do VO2pico) em duas condições ambientais: Aeróbico termoneutro (ATn) em que a temperatura foi mantida a 22-25 °C, humidade relativa entre 55-60 %; Aeróbico Calor (AC) em que a temperatura foi mantida entre 35-37 ºC, e uma humidade relativa entre 40-45%. As sessões EC foram organizados em quatro períodos (10 minutos cada), alternando cilcoergômetro (60-70% VO2pico) e duas séries de nove exercícios de força (12-15 repetições a 60-70% de 1-RM). As sessões de EC também foram testadas sob as mesmas condições acima mencionadas (concorrente termoneutra - CTn e concorrente calor - CC). As participantes foram autorizadas a beber cerca de 279ml (± 42.7ml) de água durante as sessões de exercício. As seguintes variáveis foram avaliadas: temperatura retal (Tre), frequência cardíaca (FC), taxa percepção de esforço (TPE), escala de percepção de esforço para crianças (EPEC), sensação térmica, conforto térmico, irritabilidade, cor e densidade da urinária. ANOVA de um e dois caminhos; ANOVA para medidas repetidas e os testes de Friedman e Wilcoxon (p <0,05) foram realizados com os diferentes tipos de exercícios (EA e EC), e as condições de temperatura (Tn e C) como fatores. Resultados: A análise confirmou semelhantes (p> 0,05) os níveis de hidratação, Tre e UR, no início de cada sessão de exercícios confirmando a linha de base. Os resultados mostraram diferenças entre pré e pós-exercício na Tre (AC: 37,1± 0,2 para 37,7±0,2ºC, e CC: 37,1±0,2 para 37,5±0,2°C) (p=0,001). Não foram encontradas diferenças durante as sessões CTn (p=0,967). Durante as sessões ATn, a Tre diferiu (p = 0,016), apenas no vigésimo minuto (37,1±0,2 para 37,4 ± 0,3). Além disso, não houve diferença (p=1,000) entre as sessões ATn e CTn. No entanto, houve diferença (p = 0,016) comparando a AC e CC, no minuto 35 (AC= 37,6 ± 0,2; CC= 37,4 ± 0,2 °C), e no minuto 40 (AC = 37,7 ± 0,2 e CC= 37,5 ±0,2 °C). O conforto térmico e sensação térmica foram maiores durante as sessões de calor e no exercício aeróbio (p <0,05). Não houve diferença na EPEC e irritabilidade. Conclusão: Em geral, estes resultados concluem que as adolescentes obesas respondem melhor em termos fisiológicos e perceptivos durante o EC em comparação com as sessões de EA. Além disso, os resultados demonstraram que a percepção de esforço, sensação térmica, e conforto térmico conduziu a um aumento significativo do prazer relatado no EA independente da condição térmica. Portanto, o EC pode aumentar o prazer e motivação intrínseca para a atividade física, aumentando a adesão desta população específica. / Introduction: Exercise is well known as one of the most powerful tools to prevent and control obesity. However, the reasons why overweight individuals seem even less willing than normal-weight ones to participate in, and adhere to exercise programs remain largely unknown. One of the hypotheses is that the high rates of dropouts typically found among overweight teenagers might be due to the type of exercise prescribed, and/or compromised thermoregulatory ability. The interaction between exercise and excess body weight would alter some unique variables such as, body temperature, perceived exertion, thermal comfort, and irritability, especially if exercises programs are performed in environments with high temperatures. Aim: This study investigated physiological and perceptual responses in teenager women during concurrent (CE) and aerobic exercise (AE) sessions, under two distinct thermic environmental conditions: artificially heated (Ht) and thermoneutral (Tn). Methods: Twelve obese pubescent girls (12.7 ± 0.6 years, 49.9 ± 3.0% fat) physically active and heat-acclimatized were randomly assigned to participate in four differents sessions, the AE sessions last 40-minutes each and consisted of cycling (60-70% of VO2peak) under two environmental conditions: Aerobic Thermoneutral (ATn) in which the temperature was kept to 22-25°C, and relative humidity between 55-60%; and Aerobic Heated (AHt) in which the temperature was kept between 35-37ºC, and relative humidity between 40-45%. The CE sessions were organized into four periods (10 minutes each) alternating cycling (60-70% VO2peak) and two sets of nine strength exercises [12-15 repetitions at 60-70% of 1-RM]. The CE sessions were also tested under the same above-mentioned environmental conditions (concurrent thermoneutral - CTn and concurrent heated - CHt). Participants were allowed to drink about 279ml (± 42.7ml) of water during the exercise sessions. The following variables were assessed: rectal temperature (Tre), heart rate (HR), rate of perceived exertion (RPE), perceived exertion scale for children (PESC), thermal sensation, thermal comfort, irritability, urine color, and urine specific gravity. One, and two way ANOVAs, repeated measures ANOVA, and Friedman and Wilcoxon tests (p <0.05) were performed using the different types of exercises (AE and CE), and temperature conditions (Tn and Ht) as factors. Results: The analysis confirmed similar (p> 0.05) hydration levels, Tre, and HR at the beginning of each exercise session confirming the baseline. The results showed differences between pre- and post-exercise Tre assessments (AHt: 37.1 ± 0.2 - 37.7 ± 0.2 ºC; and CHt: 37.1 ± 0.2 - 37.5 ± 0.2 °C) (p = 0.001). No differences were found during the CTn sessions (p = 0.967). During the ATn sessions, the Tre differed (p = 0.016) only during the first 20 minutes (37.1 ± 0.2 - 37.4 ± 0.3). Furthermore, no difference (p = 1.000) was found between the ATn and CTn sessions. However, the comparison between AHt and CHt differed (p = 0.016) at the 35 (AHt = 37.6 ± 0.2; and CHt = 37.4 ± 0.2 °C), and 40 minutes (AHt = 37.7 ± 0.2 and CHt = 37.5 ± 0.2 °C). The thermal comfort and thermal sensation were higher during the heated and aerobic sessions (p <0.05). No differences in the PESC, and irritability were found. Conclusion: Overall these findings conclude that overweight teenagers respond physiologically better during CE as compared to AE sessions. In addition, the results demonstrated that perceived exertion, thermal sensation, and thermal comfort led to a significant increase in reported pleasure on AE regardless of environmental condition. Over time, the CE could increase the enjoyment of and intrinsic motivation for physical activity, increasing adherence of this particular population.

A seleção para produção de leite vem aumentando a suscetibilidade de vacas leiteiras ao estresse térmico, principalmente em raças europeias em regiões tropicais e sub-tropicais. Cerca de 95% do rebanho leiteiro no Brasil é composto por animais mestiços. O objetivo deste trabalho, conduzido no campo experimental José Henrique Bruschi da Embrapa Gado de Leite, em Coronel Pacheco – MG, durante o mês de março de 2013, foi investigar alterações nos parâmetros fisiológicos de vacas leiteiras que identifiquem com maior fidedignidade o estresse calórico. Foram realizadas coletas de sangue para análise do hematócrito (Ht), contagem de eritrócitos (ERI) e contagem de hemoglobina (HEMO), além do registro da temperatura retal (TR), da frequência cardíaca (FC), da frequência respiratória (FR), do escore de ofegação (EO) em 38 fêmeas bovinas em lactação, divididas conforme o grupo genético em ½, ¾ e puras, durante seis dias nos turnos da manhã e da tarde. Os dados foram submetidos à análise da variância considerando os efeitos de grupo genético, dias, turnos e suas interações, com medidas repetidas no tempo e regressão “broken-line”. Houve efeito significativo para a interação grupo genético*dia*turno para TR, FC, FR e EO. Os valores de TR, FC, FR e EO do grupo de vacas puras HO foram maiores em relação ao grupo ¾ e esse em relação ao grupo ½. No grupo de vacas puras, as variáveis fisiológicas aumentaram linearmente com o Índice de Temperatura e Umidade (ITU), sem apresentar inflexão. O ponto de inflexão das curvas de variáveis fisiológicas ocorreu num valor de ITU mais alto para o grupo ½ em relação aos demais. Os valores de Ht e HEMO foram distintos entre os grupos genéticos, mas não variaram com o ITU, mostrando que o estresse provocado não foi suficiente para alterar os parâmetros hematológicos medidos. A média de ITU durante o turno da manhã foi de 74, quando 70, 43 e 13% das vacas puras, ¾ e ½, respectivamente, se apresentavam com a FR acima dos padrões de referência. A FR foi o melhor indicativo do estresse térmico e seu valor crítico foi de 140mov/min para as vacas Girolando e 168 mov/min para a raça Holandesa. Vacas da raça Holandesa são mais sensíveis ao estresse térmico do que cruzas Holandês-Zebuíno. / Selection for milk production has increased the susceptibility of dairy cows to heat stress, especially in European breeds reared in tropical and sub - tropical conditions. About 95% of dairy cattle in Brazil are crossbred animals. This study, conducted in the Embrapa Dairy Cattle José Henrique Bruschi experimental station, Coronel Pacheco - MG, was used to investigate changes in the physiological parameters of dairy cows to identify heat stress with greater reliability. Blood samples were collected for analysis of hematocrit (Ht), erythrocyte count (ERI) and hemoglobin count (HEMO), in addition to recording the rectal temperature (RT), heart rate (HR), respiratory rate (RR), panting score (PS) in 38 lactating cows. These varied according to genetic group (½, ¾ and pure bred Holstein (HO)), anda data was collected for six days in the morning and afternoon. Data were subjected to analysis of variance considering the effects of genetic group, days, time of day and their interactions with repeated measures and broken-line regression. Significant effects were found for the interaction between genetic group*day*time of day for RT, HR, RR and PS. These values were higher for pure HO cows were higher than in ¾ and ½ groups. In the HO group, physiological variables increased linearly with the Temperature Humidity Index, without presenting inflection in the regression. The inflection point occurred at a higher ITU highest value for the ½ group compared with the other groups. Ht and HEMO were different among genetic groups and did not vary with the ITU, showing that stress caused was not sufficient to alter the hematological parameters measured. The average THI during the morning shift was 74, when 70, 43 and 13 % of pure HO, ¾ and ½, respectively, presented FR above the standard. The FR was the best indicator of heat stress and its critical value was 140mov/min for Gir cows and 168 mov / min for Holsteins. Holstein cows are more sensitive to heat stress than crossbred Holstein- Zebu.

Dicinodontes (Therapsida: Anomodontia) compreendem os principais herbívoros do intervalo Permiano Médio-Triássico Superior. Algumas de suas características morfofuncionais cranianas têm se mostrado boas adaptações à herbivoria e ao eficiente processamento oral de materiais vegetais, bem como à termorregulação. Dentre estas, a aquisição da propalinia (movimentação ânteroposterior da mandíbula) e a substituição de um aparelho mastigatório com dentes por uma ranfoteca cobrindo boa parte da extremidade anterior do crânio são os mais característicos. Na anatomia corpórea como um todo, a aquisição de uma postura mais ereta (upright), o aumento do tamanho corpóreo e a presença de turbinais são indicativos de que o grupo evoluiu para um padrão de vida mais ativo e, consequentemente, com um maior gasto energético. Neste trabalho, é apresentada uma revisão bibliográfica sobre tais adaptações e uma discussão sobre sua origem e evolução no clado Anomodontia, focando a espécie Jachaleria candelariensis Araújo & Gonzaga, 1980 do Triássico Superior do Rio Grande do Sul, Brasil. / Dicynodonts (Therapsida: Anomodontia) comprise the main herbivores of the Middle Permian - Upper Triassic interval. Some of their morphological and functional cranial characteristics revealed to be adaptations to herbivory and efficient oral processing of plant materials, as well thermoregulation. Among these, the acquisition of propaliny (anteroposterior movements of mandible) and the replacement of the teeth by a ramphoteca covering most of the snout are the most characteristic adaptations. Regarding to their overall shape, the acquisition of a more erect (upright) gait, the increase in body size and the presence of turbinals indicate that this group evolved toward a more active lifestyle and, consequently with a most energetic cost. In this dissertation, is presented a bibliographic revision about such adaptations and a discussion about its origin and evolution within Anomodontia, focusing the Upper Triassic Jachaleria candelariensis Araújo & Gonzaga, 1980, from Rio Grande do Sul State, southern Brazil. / Los dicinodontes (Therapsida: Anomodontia) fueron los principales herbívoros durante el intervalo Pérmico Medio - Triásico Tardío. Presentaban varios caracteres morfofuncionales que reflejan adaptaciones al hábito herbívoro, así como a la termoregulación. Entre las más comunes están la adquisición de la propalinía (movimentación antero-posterior de la mandíbula) y la sustitución de un aparato masticatorio con dientes post-caninos por uno con forma de pico cubierto por una ranfoteca. Otros caracteres como la adquisición de una posición mas erecta (upright), aumento de la talla corporal y la presencia de turbinales son indicativos de que el clado evolucionó hacia un patrón de vida mas activo, y consecuentemente, de un mayor consumo de energía. En este trabajo se realizó una revisión bibliográfica de dichas adaptaciones y se discutió sobre su origen y evolución dentro del grupo Anomodontia, con un enfoque en el taxon Jachaleria candelariensis Araújo & Gonzaga, 1980 del Triásico Tardío de Rio Grande do Sul, Brasil.