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1.
PLoS One ; 15(2): e0229335, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32084208

RESUMO

Acclimation resulting from low- to moderate-intensity physical exertion in the heat induces several thermoregulatory adaptations, including slower exercise-induced increases in core body temperature. However, few studies have investigated the thermoregulatory adaptations induced by high-intensity interval training (HIIT) protocols. Thus, the present study aimed to compare the adaptations in rats' thermoregulatory parameters and aerobic performance observed after two different heat acclimation regimens consisting of HIIT protocols performed in a hot environment. Twenty-three adult male Wistar rats were initially subjected to an incremental-speed exercise at 32°C until they were fatigued and then randomly assigned to one of the following three heat acclimation strategies: passive heat exposure without any exercise (untrained controls-UN; n = 7), HIIT performed at the maximal aerobic speed (HIIT100%; n = 8) and HIIT performed at a high but submaximal speed (HIIT85%; n = 8). Following the two weeks of interventions, the rats were again subjected to a fatiguing incremental exercise at 32°C, while their colonic temperature (TCOL) was recorded. The workload performed by the rats and their thermoregulatory efficiency were calculated. After the intervention period, rats subjected to both HIIT protocols attained greater workloads (HIIT100%: 313.7 ± 21.9 J vs. HIIT85%: 318.1 ± 32.6 J vs. UN: 250.8 ± 32.4 J; p < 0.01) and presented a lower ratio between the change in TCOL and the distance travelled (HIIT100%: 4.95 ± 0.42°C/km vs. HIIT85%: 4.33 ± 0.59°C/km vs. UN: 6.14 ± 1.03°C/km; p < 0.001) when compared to UN rats. The latter finding indicates better thermoregulatory efficiency in trained animals. No differences were observed between rats subjected to the two HIIT regimens. In conclusion, the two HIIT protocols induce greater thermoregulatory adaptations and performance improvements than passive heat exposure. These adaptations do not differ between the two training protocols investigated in the present study.


Assuntos
Adaptação Fisiológica/fisiologia , Regulação da Temperatura Corporal/fisiologia , Treinamento Intervalado de Alta Intensidade/métodos , Temperatura Alta , Condicionamento Físico Animal/fisiologia , Esforço Físico/fisiologia , Animais , Masculino , Ratos , Ratos Wistar , Fatores de Tempo
3.
PLoS One ; 15(1): e0227700, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31971994

RESUMO

In vertebrates, the embryonic environment is known to affect the development and the health of individuals. In broiler chickens, the thermal-manipulation (TM) of eggs during the incubation period was shown to improve heat tolerance at slaughter age (35 days of age) in association with several modifications at the molecular, metabolic and physiological levels. However, little is known about the Japanese quail (Coturnix japonica), a closely related avian species widely used as a laboratory animal model and farmed for its meat and eggs. Here we developed and characterized a TM procedure (39.5°C and 65% relative humidity, 12 h/d, from days 0 to 13 of incubation) in quails by analyzing its short and long-term effects on zootechnical, physiological and metabolic parameters. Heat-tolerance was tested by a heat challenge (36°C for 7h) at 35 days of age. TM significantly reduced the hatching rate of the animals and increased mortality during the first four weeks of life. At hatching, TM animals were heavier than controls, but lighter at 25 days of age for both sexes. Thirty-five days after hatching, TM decreased the surface temperature of the shank in females, suggesting a modulation of the blood flow to maintain the internal temperature. TM also increased blood partial pressure and oxygen saturation percentage at 35 days of age in females, suggesting a long-term modulation of the respiration physiology. Quails physiologically responded to the heat challenge, with a modification of several hematologic and metabolic parameters, including an increase in plasma corticosterone concentration. Several physiological parameters such as beak surface temperature and blood sodium concentration revealed that TM birds responded differently to the heat challenge compared to controls. Altogether, this first comprehensive characterization of TM in Japanese quail showed durable effects that may affect the response of TM quails to heat.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Coturnix/embriologia , Animais , Antioxidantes/metabolismo , Embrião de Galinha , Galinhas/crescimento & desenvolvimento , Galinhas/fisiologia , Coturnix/crescimento & desenvolvimento , Coturnix/fisiologia , Desenvolvimento Embrionário/fisiologia , Feminino , Gases/sangue , Temperatura Alta , Masculino , Termotolerância/fisiologia
4.
Proc Natl Acad Sci U S A ; 117(3): 1566-1572, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31919285

RESUMO

While surface microstructures of butterfly wings have been extensively studied for their structural coloration or optical properties within the visible spectrum, their properties in infrared wavelengths with potential ties to thermoregulation are relatively unknown. The midinfrared wavelengths of 7.5 to 14 µm are particularly important for radiative heat transfer in the ambient environment, because of the overlap with the atmospheric transmission window. For instance, a high midinfrared emissivity can facilitate surface cooling, whereas a low midinfrared emissivity can minimize heat loss to surroundings. Here we find that the midinfrared emissivity of butterfly wings from warmer climates such as Archaeoprepona demophoon (Oaxaca, Mexico) and Heliconius sara (Pichincha, Ecuador) is up to 2 times higher than that of butterfly wings from cooler climates such as Celastrina echo (Colorado) and Limenitis arthemis (Florida), using Fourier-transform infrared (FTIR) spectroscopy and infrared thermography. Our optical computations using a unit cell approach reproduce the spectroscopy data and explain how periodic microstructures play a critical role in the midinfrared. The emissivity spectrum governs the temperature of butterfly wings, and we demonstrate that C. echo wings heat up to 8 °C more than A. demophoon wings under the same sunlight in the clear sky of Irvine, CA. Furthermore, our thermal computations show that butterfly wings in their respective habitats can maintain a moderate temperature range through a balance of solar absorption and infrared emission. These findings suggest that the surface microstructures of butterfly wings potentially contribute to thermoregulation and provide an insight into butterflies' survival.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Borboletas/fisiologia , Raios Infravermelhos , Asas de Animais/fisiologia , Animais , Colorado , Biologia Computacional , Ecossistema , Equador , Florida , México , Modelos Biológicos , Fenômenos Ópticos , Análise Espectral , Luz Solar , Temperatura , Asas de Animais/ultraestrutura
5.
Artigo em Inglês | MEDLINE | ID: mdl-31861405

RESUMO

We tested the hypothesis that thermal behavior alleviates thermal discomfort and accelerates core temperature recovery following low intensity exercise. Methods: In a 27 0 C, 48 6% relative humidity environment, 12 healthy subjects (six females) completed 60 min of exercise followed by 90 min of seated recovery on two occasions. Subjects wore a suit top perfusing 34 ± 0 °C water during exercise. In the control trial, this water continually perfused throughout recovery. In the behavior trial, the upper body was maintained thermally comfortable by pressing a button to receive cool water (3 2 °C) perfusing through the top for 2 min per button press. Results: Physiological variables (core temperature, p ≥ 0.18; mean skin temperature, p = 0.99; skin wettedness, p ≥ 0.09; forearm skin blood flow, p = 0.29 and local axilla sweat rate, p = 0.99) did not differ between trials during exercise. Following exercise, mean skin temperature decreased in the behavior trial in the first 10 min (by -0.5 0.7 °C, p < 0.01) and upper body skin temperature was reduced until 70 min into recovery (by 1.8 1.4 °C, p < 0.05). Core temperature recovered to pre-exercise levels 17 31 min faster (p = 0.02) in the behavior trial. There were no differences in skin blood flow or local sweat rate between conditions during recovery (p ≥ 0.05). Whole-body thermal discomfort was reduced (by -0.4 0.5 a.u.) in the behavior trial compared to the control trial within the first 20 min of recovery (p ≤ 0.02). Thermal behavior via upper body cooling resulted in augmented cumulative heat loss within the first 30 min of recovery (Behavior: 288 92 kJ; Control: 160 44 kJ, p = 0.02). Conclusions: Engaging in thermal behavior that results in large reductions in mean skin temperature following exercise accelerates the recovery of core temperature and alleviates thermal discomfort by promoting heat loss.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Exercício Físico/fisiologia , Adulto , Feminino , Temperatura Alta , Humanos , Masculino , Temperatura Cutânea , Sudorese , Adulto Jovem
6.
J Sports Med Phys Fitness ; 59(10): 1601-1607, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31694361

RESUMO

BACKGROUND: Outdoor exercise often proceeds in rainy conditions. However, there are very few studies reporting the physiological effects of cold with rain or wet-cold exposure on humans during exercise. The purpose of this study was to investigate the effects of rain on physiological responses during running exercise at 80% V̇Omax in the cold. METHODS: Twelve healthy men (age: 21.7±3.3 years; height: 1.760±0.085 m; body weight: 68.8±7.1 kg; maximal oxygen consumption: 67.3±5.00 mL/kg/min) exercised on a treadmill at 80% V̇Omax intensity for 60 minutes with rain (RAIN) or not (CON) at 5 °C. RESULTS: Rectal temperature was significantly lower in RAIN than in CON at 10, 40, 50, and 60 minutes (P<0.05). Mean weighted skin temperature was significantly lower in RAIN than in CON during exercise (P<0.05). Oxygen consumption and rating of perceived exertion were significantly higher in RAIN than in CON at 50 and 60 minutes (P<0.05). Plasma lactate was significantly higher in RAIN than in CON at 10 minutes and from 40 to 60 minutes (P<0.05). Plasma norepinephrine levels were significantly higher in RAIN than in CON at 10 minutes and from 40 to 60 minutes (P<0.05). CONCLUSIONS: These results suggest that rain increased heat loss during the early phase of exercise in the cold, then heat production increased and transiently suppressed cold stress. However, with time, body heat loss intensified due to increasing wet area, and then energy expenditure and plasma lactate increased due to cold stress. Therefore, rain may decrease exercise performance and affect sport safety.


Assuntos
Temperatura Baixa/efeitos adversos , Metabolismo Energético/fisiologia , Chuva , Corrida/fisiologia , Adolescente , Adulto , Regulação da Temperatura Corporal/fisiologia , Estudos de Casos e Controles , Teste de Esforço/métodos , Humanos , Ácido Láctico/sangue , Masculino , Consumo de Oxigênio/fisiologia , Temperatura Cutânea , Adulto Jovem
8.
Arq. bras. med. vet. zootec. (Online) ; 71(5): 1750-1758, set.-out. 2019. tab, graf, ilus
Artigo em Português | LILACS, VETINDEX | ID: biblio-1038659

RESUMO

The effects of housing lactating sows at different locations in a shed with evaporative cooling system (ECS) on their thermoregulation and reproductive and productive performance of the sow and the litter in summer were determined. 34 females were used in the three lines of cages at these locations: near the pad cooling; in the middle of the shed and near the exhaust fans. The air temperature and the temperature and humidity index (THI) were lower near the pad cooling (22.38ºC, 71.84) than the middle (24.56ºC, 74.82) and near the exhaust fans (25.00°C, 75.62). Respiratory rate, rectal and surface temperatures were lower in sows near the pad cooling (43.67 breaths.min -1 , 38.40°C; 29.51°C) than in the center (52.04 breaths.min -1 ; 38.48ºC; 32.02ºC) and near the exhaust fans (56.38 breaths.min-1, 38.93ºC; 32.52ºC). The backfat thickness, the weaning-estrus interval and daily average consumption of the sows, number of weaning piglets, corporal mass and daily average gain of the piglets were not influenced by the location of housing in the shed. Lactating sows housed in the middle and near the exhaust fans in the ECS presented increased thermoregulation physiological variables, however, this did not impair the performance.(AU)


Assuntos
Animais , Feminino , Gravidez , Suínos/crescimento & desenvolvimento , Temperatura , Regulação da Temperatura Corporal/fisiologia , Bem-Estar do Animal/organização & administração , Transtornos de Estresse por Calor/prevenção & controle , Abrigo para Animais/organização & administração
9.
Physiol Biochem Zool ; 92(6): 544-553, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31560253

RESUMO

Archaic mammals became exclusively nocturnal by the Late Triassic, and today, the majority of extant mammals remain nocturnal. Although there is ample morphological and physiological evidence supporting Late Mesozoic nocturnalism, a succinct hypothesis for why mammals became nocturnal remains elusive. Here, I propose a hypothesis that, with the onset of body size miniaturization in the Triassic and the concomitant evolution of fur and increased mass-specific metabolic rate and hence body temperature, small mammals became obligatorily nocturnal in order to avoid poor sperm quality, hyperthermia, and high rates of evaporative water loss and to maximize foraging time. The hypothesis hinges heavily on the assumption that, with the absence of externalized testes, the maximum optimum temperature of about 36°C for spermatogenesis was subject to strong stabilizing selection that placed a ceiling on increases in metabolic rate and body temperature. Heat-dissipating capacity during the daytime during the Triassic, Jurassic, and Cretaceous was thereby compromised. The release from the constraint of the optimum temperature of spermatogenesis occurred in placental mammals only with the advent of the externalization of testes in the scrotum in Boreotheria in the Cenozoic or, with the recent claim that the scrotum is plesiomorphic in mammals, as early as the Jurassic with the origin of the marsupials.


Assuntos
Evolução Biológica , Ritmo Circadiano , Mamíferos , Espermatozoides/fisiologia , Animais , Regulação da Temperatura Corporal/fisiologia , Genitália Masculina/fisiologia , Masculino
10.
Nat Commun ; 10(1): 4077, 2019 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-31501432

RESUMO

Climatic conditions changing over time and space shape the evolution of organisms at multiple levels, including temperate lizards in the family Lacertidae. Here we reconstruct a dated phylogenetic tree of 262 lacertid species based on a supermatrix relying on novel phylogenomic datasets and fossil calibrations. Diversification of lacertids was accompanied by an increasing disparity among occupied bioclimatic niches, especially in the last 10 Ma, during a period of progressive global cooling. Temperate species also underwent a genome-wide slowdown in molecular substitution rates compared to tropical and desert-adapted lacertids. Evaporative water loss and preferred temperature are correlated with bioclimatic parameters, indicating physiological adaptations to climate. Tropical, but also some populations of cool-adapted species experience maximum temperatures close to their preferred temperatures. We hypothesize these species-specific physiological preferences may constitute a handicap to prevail under rapid global warming, and contribute to explaining local lizard extinctions in cool and humid climates.


Assuntos
Meio Ambiente , Variação Genética , Genoma , Lagartos/genética , Lagartos/fisiologia , Temperatura , Animais , Regulação da Temperatura Corporal/fisiologia , Clima , Evolução Molecular , Filogenia
11.
Nature ; 572(7771): 651-654, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31413362

RESUMO

The origins of endothermy in birds and mammals are important events in vertebrate evolution. Endotherms can maintain their body temperature (Tb) over a wide range of ambient temperatures primarily using the heat that is generated continuously by their high basal metabolic rate (BMR)1. There is also an important positive feedback loop as Tb influences BMR1-3. Owing to this interplay between BMRs and Tb, many ecologists and evolutionary physiologists posit that the evolution of BMR and Tb must have been coupled during the radiation of endotherms3-5, changing with similar trends6-8. However, colder historical environments might have imposed strong selective pressures on BMR to compensate for increased rates of heat loss and to keep Tb constant9-12. Thus, adaptation to cold ambient temperatures through increases in BMR could have decoupled BMR from Tb and caused different evolutionary routes to the modern diversity in these traits. Here we show that BMR and Tb were decoupled in approximately 90% of mammalian phylogenetic branches and 36% of avian phylogenetic branches. Mammalian BMRs evolved with rapid bursts but without a long-term directional trend, whereas Tb evolved mostly at a constant rate and towards colder bodies from a warmer-bodied common ancestor. Avian BMRs evolved predominantly at a constant rate and without a long-term directional trend, whereas Tb evolved with much greater rate heterogeneity and with adaptive evolution towards colder bodies. Furthermore, rapid shifts that lead to both increases and decreases in BMRs were linked to abrupt changes towards colder ambient temperatures-although only in mammals. Our results suggest that natural selection effectively exploited the diversity in mammalian BMRs under diverse, often-adverse historical thermal environments.


Assuntos
Metabolismo Basal/fisiologia , Evolução Biológica , Temperatura Corporal/fisiologia , Animais , Aves/classificação , Aves/metabolismo , Regulação da Temperatura Corporal/fisiologia , Mamíferos/classificação , Mamíferos/metabolismo , Filogenia
12.
J Clin Neurosci ; 69: 7-14, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31447370

RESUMO

BACKGROUND: Cervical spinal cord injury (cSCI) is a major public health concern in the young population as per the estimation of the annual global report, which concluded that the amount of incidence in this area ranged between 11.5 and 53.4 cases per million population. Moreover, Despite the many evaluations conducted to unveil the physiological and thermo logical complications caused to the human body after a cervical spinal cord injury, the fundamental pathophysiology about this type of injury is still inconclusive. OBJECTIVE: This review attempts to provide a better understanding to the various changes caused to the body after a cSCI. It focuses on the alterations in blood circulation, energy expenditure (EE), sweating, shivering responses and consequently disruption in body temperature regulation. METHODS: Various research engines such as Scopus, PubMed, Embase, Web of Science, EBSCO, and Cochrane Library databases were searched by two independent investigators. 17 studies out of 102 were included based on eligibility criteria: patients with complete and/or incomplete cSCI; minimum of 5 patients as participants; and control group of able Bodied People (AB). RESULTS: Following cSCI, EE decreases by 10% (p < 0.05) due to reduction in lean body mass; cardiac output decrements by 27% (p < 0.05) following the change in arterial blood vessel structure, and finally; thermoregulatory responses were disturbed because of the absence or decrease in vasodilation, vasoconstriction, sudomotor (autonomic activation of sweat glands) and shivering responses. CONCLUSIONS: The body undergoes significant thermoregulatory changes following spinal cord injury. Understanding the pathophysiology of spinal cord injury and its effect on the human body can provide us an insight to develop adequate treatment modalities that tackle the problem of thermal dysregulation in people with cSCI.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Fenômenos Fisiológicos Cardiovasculares , Medula Cervical/fisiopatologia , Traumatismos da Medula Espinal/fisiopatologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
13.
J Therm Biol ; 84: 208-213, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31466755

RESUMO

There was no clear evidence of the TRPA1 ion channel involvement in the formation of thermoregulatory responses. The present results convincingly show that the skin TRPA1 ion channel activation has significant influence on the formation of thermoregulatory responses of the body to cooling; it is especially strongly manifested for the metabolic component. At the TRPA1 activation by its agonist AITC (0.04%), an enhancement in thermoregulatory responses is observed: the temperature thresholds for the first phase and the second one of the metabolic response decrease, the values of all components of the metabolic response considerably increase: the increment of oxygen consumption in the first phase increases from 1.8 ± 0.24 in the control to 2.9 ± 0.35 ml/min*kg under AITC, P = 0.04; the increment of oxygen consumption in the second phase increases from 6.2 ± 2.06 to 17.4 ± 1.20 ml/min*kg, P = 0.002, as well as shivering rises from 7.8 ± 1.79 to 15.4 ± 1.87 mV, P = 0.011. In consideration of our previous results on the influence of TRPM8 ion channel activation on thermoregulatory responses (Kozyreva et al., J. Therm.Biol., 2010) it is obvious that the TRPM8 and TRPA1 ion channels have a pronounced, but unequal effects on the values of different phases of the metabolic response to cold. The TRPM8 activation manifests itself in an increase of value only the urgent first phase, this phase is associated with carbohydrate metabolism. As the recent results have shown the influence of the TRPA1 activation is realized predominantly in the clearly marked increase in the second phase of the metabolic response associated with lipid metabolism, as well as in evident shivering gain. The ability to predominantly control different parameters of thermoregulatory responses to cold may indicate the importance of both the TRPM8 and the TRPA1 ion channels in the processes of maintaining temperature homeostasis. The obtained data testify to the joint sequential operation of these thermosensitive ion channels.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Fenômenos Fisiológicos da Pele , Canal de Cátion TRPA1/fisiologia , Canais de Cátion TRPM/fisiologia , Animais , Temperatura Baixa , Masculino , Ratos Wistar
14.
J Therm Biol ; 84: 228-235, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31466758

RESUMO

Naked mole-rats are among the most hypoxia-tolerant mammals but have a poor thermoregulatory capacity due to their lack of insulating fur and fat, and small body size. In acute hypoxia, naked mole-rat body temperature (Tb) decreases to ambient temperature (Ta) but the mechanisms that underlie this thermoregulatory response are unknown. We hypothesized 1) that naked mole-rat blood vessels vasodilate during hypoxia to shunt heat toward the body surface and/or 2) that they augment heat loss through evaporative cooling. Using open-flow respirometry (indirect calorimetry) we explored metabolic and thermoregulatory strategies of naked mole-rats exposed to hypoxia (7% O2 for 1 h) at two relative humidities (RH; 50 or 100% water saturation), and in two Ta's (25 and 30 °C), alone, and following treatment with the vasoconstrictor angiotensin II (ANGII). We found that Tb and metabolic rate decreased in hypoxia across all treatment groups but that neither RH nor ANGII effected either variable in hypoxia. Conversely, both Tb and metabolic rate were reduced in 100% RH or by ANGII treatment in normoxia at 25 °C, and therefore the absolute change in both variables with the onset of hypoxia was reduced when vasodilation or evaporative cooling were prevented. We conclude that naked mole-rats employ evaporative cooling and vasodilation to thermoregulate in normoxia and in 25 °C but that neither mechanism is involved in thermoregulatory changes during acute hypoxia. These findings suggest that NMRs may employ passive strategies such as reducing thermogenesis to reduce Tb in hypoxia, which would support metabolic rate suppression.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Hipóxia/fisiopatologia , Ratos-Toupeira/fisiologia , Vasodilatação/fisiologia , Animais , Metabolismo Basal , Feminino , Masculino
15.
Sensors (Basel) ; 19(17)2019 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-31450666

RESUMO

In recent years, physiological features have gained more attention in developing models of personal thermal comfort for improved and accurate adaptive operation of Human-In-The-Loop (HITL) Heating, Ventilation, and Air-Conditioning (HVAC) systems. Pursuing the identification of effective physiological sensing systems for enhancing flexibility of human-centered and distributed control, using machine learning algorithms, we have investigated how heat flux sensing could improve personal thermal comfort inference under transient ambient conditions. We have explored the variations of heat exchange rates of facial and wrist skin. These areas are often exposed in indoor environments and contribute to the thermoregulation mechanism through skin heat exchange, which we have coupled with variations of skin and ambient temperatures for inference of personal thermal preferences. Adopting an experimental and data analysis methodology, we have evaluated the modeling of personal thermal preference of 18 human subjects for well-known classifiers using different scenarios of learning. The experimental measurements have revealed the differences in personal thermal preferences and how they are reflected in physiological variables. Further, we have shown that heat exchange rates have high potential in improving the performance of personal inference models even compared to the use of skin temperature.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Aprendizado de Máquina , Monitorização Fisiológica , Fenômenos Fisiológicos da Pele , Ar Condicionado , Algoritmos , Temperatura Alta , Humanos , Temperatura Cutânea/fisiologia , Sensação Térmica/fisiologia , Ventilação
16.
Rev Bras Enferm ; 72(4): 1114-1118, 2019 Aug 19.
Artigo em Inglês, Português | MEDLINE | ID: mdl-31432973

RESUMO

OBJECTIVE: to report the experience of conducting directed temperature control of a post-cardiopulmonary resuscitation patient, with reduced and basic inputs available at the institution. METHOD: an experience report of directed temperature control in patient (age 15 years), after four hours of cardiopulmonary resuscitation in an Intensive Care Unit of a hospital in São Paulo State countryside in 2016, according to the protocol suggested by the American Heart Association, in 2015. There were applications of cold compresses, plastic bags with crushed ice and rectal temperature control. RESULTS: after eight hours, temperature had reached 93.2 ºF. Body cooling was maintained for 24 hours. However, bags with crushed ice were used in the first 6 hours. CONCLUSION: conduct of nurses to obtain the body cooling with reduced and basic inputs was effective during the stay at the Intensive Care Unit.


Assuntos
Reanimação Cardiopulmonar/efeitos adversos , Hipotermia Induzida/métodos , Peritonite/complicações , Dor Abdominal/etiologia , Adolescente , Apendicite/complicações , Apendicite/cirurgia , Regulação da Temperatura Corporal/fisiologia , Reanimação Cardiopulmonar/métodos , Reanimação Cardiopulmonar/normas , Feminino , Febre/etiologia , Humanos , Peritonite/cirurgia , Tomografia Computadorizada por Raios X/métodos , Vômito/etiologia
17.
J Strength Cond Res ; 33(10): 2608-2615, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31361730

RESUMO

Otani, H, Goto, T, Goto, H, Hosokawa, Y, and Shirato, M. Solar radiation exposure has diurnal effects on thermoregulatory responses during high-intensity exercise in the heat outdoors. J Strength Cond Res 33(10): 2608-2615, 2019-This study investigated the diurnal effects of variations in solar radiation associated with changing solar elevation angle on thermoregulatory responses during high-intensity exercise in the heat outdoors. Ten male high school soccer players completed two 2-hour soccer training sessions under a clear sky in the heat of summer. These sessions were commenced at 0900 hours (AM) and 1600 hours (PM) on separate days. Solar radiation and elevation angle were higher in AM (820-1,070 W·m and 45-69°) than PM (620-110 W·m and 34-10°: both p < 0.001). Neither ambient temperature (AM 29-32° C; PM 31-31° C) nor wet-bulb globe temperature was different between trials. Although mean skin temperature was not different between trials, infrared tympanic temperature was higher at the end of exercise in AM than PM (p < 0.001). Heart rate (p < 0.01) and body heat gain from the sun (p < 0.001) were greater during exercise in AM than PM. Dry heat loss was smaller, but evaporative heat loss was greater in AM than PM (both p < 0.001). Thermal sensation and rating of perceived exertion were similar between trials, but GPS measurements showed a less total distance and distance covered by walking, jogging, and running in AM than PM (p < 0.01). This study demonstrates a greater thermoregulatory strain in AM than PM during 2-hour high-intensity soccer training in the heat under a clear sky. This observation is accompanied by a progressive increase in environmental heat stress with rising solar radiation and elevation angle in AM and a greater body heat gain from the sun in AM compared with PM.


Assuntos
Regulação da Temperatura Corporal/efeitos da radiação , Exposição à Radiação , Futebol/fisiologia , Estresse Fisiológico/efeitos da radiação , Luz Solar , Adolescente , Temperatura Corporal , Regulação da Temperatura Corporal/fisiologia , Ritmo Circadiano/efeitos da radiação , Exercício Físico/fisiologia , Frequência Cardíaca , Temperatura Alta , Humanos , Masculino , Estresse Fisiológico/fisiologia , Sensação Térmica , Perda Insensível de Água
18.
Neuron ; 103(2): 309-322.e7, 2019 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-31151773

RESUMO

Body temperature control is essential for survival. In mammals, thermoregulation is mediated by the preoptic area of anterior hypothalamus (POA), with ∼30% of its neurons sensitive to brain temperature change. It is still unknown whether and how these temperature-sensitive neurons are involved in thermoregulation, because for eight decades they have only been identified via electrophysiological recording. By combining single-cell RNA-seq with whole-cell patch-clamp recordings, we identified Ptgds as a genetic marker for temperature-sensitive POA neurons. Then, we demonstrated these neurons' role in thermoregulation via chemogenetics. Given that Ptgds encodes the enzyme that synthesizes prostaglandin D2 (PGD2), we further explored its role in thermoregulation. Our study revealed that rising temperature of POA alters the activity of Ptgds-expressing neurons so as to increase PGD2 production. PGD2 activates its receptor DP1 and excites downstream neurons in the ventral medial preoptic area (vMPO) that mediates body temperature decrease, a negative feedback loop for thermoregulation.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Neurônios/fisiologia , Área Pré-Óptica/citologia , Área Pré-Óptica/fisiologia , Prostaglandina D2/metabolismo , Temperatura , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Animais , Temperatura Corporal/efeitos dos fármacos , Temperatura Corporal/fisiologia , Regulação da Temperatura Corporal/genética , Proteína 9 Associada à CRISPR/genética , Proteína 9 Associada à CRISPR/metabolismo , Clozapina/farmacologia , Dinoprostona/genética , Dinoprostona/metabolismo , Antagonistas de Aminoácidos Excitatórios/farmacologia , Regulação da Expressão Gênica/genética , Células HEK293 , Humanos , Locomoção/efeitos dos fármacos , Locomoção/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurônios/efeitos dos fármacos , Área Pré-Óptica/efeitos dos fármacos , Prostaglandina D2/genética
19.
J Sci Med Sport ; 22(8): 912-917, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31151878

RESUMO

OBJECTIVES: The study examined if three feasible strategies involving additional in-play cooling periods attenuate the core (rectal) temperature rise during simulated football matches. DESIGN: Four counterbalanced experimental trials in an environmental chamber set to 35 °C ambient temperature, 55% relative humidity, and 30 °C WBGT. METHODS: Twelve healthy well-trained football players completed a regular simulated match (REG), regular simulated match with additional 3-min cooling periods at the 30-min mark of each half inclusive of chilled water consumption (COOLwater), regular simulated match with additional 3-min cooling periods at the 30-min mark of each half inclusive of chilled water consumption and the application of an ice towel around the neck (COOLtowel), regular simulated match with an extended (+5 min; total of 20-min) half-time break (HTextended). RESULTS: The difference in rectal temperature change was significantly lower in the COOLwater (-0.25 °C), COOLtowel (-0.28 °C), and HTextended (-0.21 °C) trials in comparison to the REG (all p < 0.05). Exercising heart rate and session rating of perceived exertion was lower in the COOLwater (-13 bpm; -1.4 au), COOLtowel (-10 bpm; -1.3 au), and HTextended (-8 bpm; -0.9 au) trials in comparison to the REG trial (all p < 0.05). The cooling interventions did not significantly change skin temperature or thermal sensation in comparison to the REG (all p > 0.05). CONCLUSIONS: All three cooling interventions attenuated core body thermal strain during simulated matches. The laboratory-based study supports the use of brief in-play cooling periods as a means to attenuate the rise in core temperature during matches in hot and humid conditions.


Assuntos
Regulação da Temperatura Corporal/fisiologia , Crioterapia/métodos , Futebol Americano/fisiologia , Transtornos de Estresse por Calor/prevenção & controle , Temperatura Alta/efeitos adversos , Esforço Físico/fisiologia , Humanos , Masculino , Descanso/fisiologia , Água , Adulto Jovem
20.
Wilderness Environ Med ; 30(2): 163-176, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31056372

RESUMO

INTRODUCTION: We compared the effectiveness of 5 heated hypothermia wrap systems. METHODS: Physiologic and subjective responses were determined in 5 normothermic subjects (1 female) for 5 heated hypothermia wraps (with vapor barrier and chemical heat sources) during 60 min of exposure to a temperature of -22°C. The 5 systems were 1) user-assembled; 2) Doctor Down Rescue Wrap; 3) hypothermia prevention and management kit (HPMK); 4) MARSARS Hypothermia Stabilizer Bag; and 5) Wiggy's Victims Casualty Hypothermia Bag. Core and skin temperature, metabolic heat production, skin heat loss, and body net heat gain were determined. Subjective responses were also evaluated for whole body cold discomfort, overall shivering rating, overall temperature rating, and preferential ranking. RESULTS: The Doctor Down and user-assembled systems were generally more effective, with higher skin temperatures and lower metabolic heat production; they allowed less heat loss, resulting in higher net heat gain (P<0.05). HPMK had the lowest skin temperature and highest shivering heat production and scored worse than the other 4 systems for the "whole body cold discomfort" and "overall temperature" ratings (P<0.05). CONCLUSIONS: The user-assembled and Doctor Down systems were most effective, and subjects were coldest with the HPMK system. However, it is likely that any of the tested systems would be viable options for wilderness responders, and the choice would depend on considerations of cost; volume, as it relates to available space; and weight, as it relates to ability to carry or transport the system to the patient.


Assuntos
Temperatura Baixa , Hipotermia/prevenção & controle , Reaquecimento/instrumentação , Adolescente , Adulto , Temperatura Corporal , Regulação da Temperatura Corporal/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tremor por Sensação de Frio , Temperatura Cutânea , Medicina Selvagem/instrumentação
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