Heat-related risk at Paris 2024: a proposal for classification and review of International Federations policies.

Several International Federations (IFs) employ specific policies to protect athletes' health from the danger of heat. Most policies rely on the measurement of thermal indices such as the Wet Bulb Globe Temperature (WBGT) to estimate the risk of heat-related illness. This review summarises the policies implemented by the 32 IFs of the 45 sports included in the Paris 2024 Olympic Games. It provides details into the venue type, measured parameters, used thermal indices, measurement procedures, mitigation strategies and specifies whether the policy is a recommendation or a requirement. Additionally, a categorisation of sports' heat stress risk is proposed. Among the 15 sports identified as high, very high or extreme risk, one did not have a heat policy, three did not specify any parameter measurement, one relied on water temperature, two on air temperature and relative humidity, seven on WBGT (six measured on-site and one estimated) and one on the Heat Stress Index. However, indices currently used in sports have been developed for soldiers or workers and may not adequately reflect the thermal strain endured by athletes. Notably, they do not account for the athletes' high metabolic heat production and their level of acclimation. It is, therefore, worthwhile listing the relevance of the thermal indices used by IFs to quantify the risk of heat stress, and in the near future, develop an index adapted to the specific needs of athletes.

High-density thermal sensitivity maps of the body of people with multiple sclerosis: Implications for inclusive personal comfort systems.

Inclusive thermal comfort solutions should accommodate the need of clinical groups such as people with Multiple Sclerosis (pwMS), who experience abnormal thermal sensitivity. The aim of this study was to develop high-density body maps of temperature sensitivity in pwMS to inform the design of patient-centred personal comfort systems. Fourteen pwMS (6 M/8 F; 48.6 ± 10.0 y) and 13 healthy individuals (CTR; 5 M/8 F; 47.8 ± 10.4) underwent a quantitative sensory test in a thermoneutral environment, during which they rated their local thermal sensations arising from the application of warm (39°C) and cold (27°C) stimuli to 115 bilateral body sites across the face, torso, upper and lower limbs. We used a z-transformation to create maps of hypo- and hyper-sensitivity for each individual MS participant using normative CTR data. We found that 50% of pwMS (N = 7/14) presented a loss of cold sensitivity over the upper limb, and a loss of warm sensitivity over the feet. Furthermore, 36% of pwMS (N = 5) presented warm hyper-sensitivity over the upper limb. Finally, cold sensitivity loss and warm sensitivity gain were more evenly distributed and affected a greater proportion of skin sites in MS (i.e. cold hypo-sensitivity = 44% of tested sites; warm hyper-sensitivity = 14%) than warm sensitivity loss (i.e. 10%), which was more focused on sites such as the feet. Our findings highlight the need to consider "thermosensory corrective power" when designing personal comfort systems, to accommodate either thermosensory loss or gain in pwMS. Our approach to clinical body mapping may support this process and help meeting the unique thermal needs of vulnerable individuals.

Hot climate, hot koalas: the role of weather, behaviour and disease on thermoregulation.

Thermoregulation is critical for endotherms living in hot, dry conditions, and maintaining optimal core body temperature (Tb) in a changing climate is an increasingly challenging task for mammals. Koalas (Phascolarctos cinereus) have evolved physiological and behavioural strategies to maintain homeostasis and regulate their Tb but are thought to be vulnerable to prolonged heat. We investigated how weather, behaviour and disease influence Tb for wild, free-living koalas during summer in north-west New South Wales. We matched Tb with daily behavioural observations in an ageing population where chlamydial disease is prevalent. Each individual koala had similar Tb rhythms (average Tb = 36.4 ± 0.05°C), but male koalas had higher Tb amplitude and more pronounced daily rhythm than females. Disease disrupted the 24-hr circadian pattern of Tb. Koala Tb increased with ambient temperature (Ta). On the hottest day of the study (maximum Ta = 40.8°C), we recorded the highest (Tb = 40.8°C) but also the lowest (Tb = 32.4°C) Tb ever documented for wild koalas, suggesting that they are more heterothermic than previously recognized. This requires individuals to predict days of extreme Ta from overnight and early morning conditions, adjusting Tb regulation accordingly, and it has never been reported before for koalas. The large diel amplitude and low minimum Tb observed suggest that koalas at our study site are energetically and nutritionally compromised, likely due to their age. Behaviour (i.e. tree hugging and drinking water) was not effective in moderating Tb. These results indicate that Ta and koala Tb are strongly interconnected and reinforce the importance of climate projections for predicting the future persistence of koalas throughout their current distribution. Global climate models forecast that dry, hot weather will continue to escalate and drought events will increase in frequency, duration and severity. This is likely to push koalas and other arboreal folivores towards their thermal limit.

The Effect of Brief Warming during Induction of General Anesthesia and Warmed Intravenous Fluid on Intraoperative Hypothermia in Patients Undergoing Urologic Surgery.

Background and Objectives: Transurethral urologic surgeries frequently lead to hypothermia due to bladder irrigation. Prewarming in the preoperative holding area can reduce the risk of hypothermia but disrupts surgical workflow, preventing it from being of practical use. This study explored whether early intraoperative warming during induction of anesthesia, known as peri-induction warming, using a forced-air warming device combined with warmed intravenous fluid could prevent intraoperative hypothermia. Materials and Methods: Fifty patients scheduled for transurethral resection of the bladder (TURB) or prostate (TURP) were enrolled and were randomly allocated to either the peri-induction warming or control group. The peri-induction warming group underwent whole-body warming during anesthesia induction using a forced-air warming device and was administered warmed intravenous fluid during surgery. In contrast, the control group was covered with a cotton blanket during anesthesia induction and received room-temperature intravenous fluid during surgery. Core temperature was measured upon entrance to the operating room (T0), immediately after induction of anesthesia (T1), and in 10 min intervals until the end of the operation (Tend). The incidence of intraoperative hypothermia, change in core temperature (T0-Tend), core temperature drop rate (T0-Tend/[duration of anesthesia]), postoperative shivering, and postoperative thermal comfort were assessed. Results: The incidence of intraoperative hypothermia did not differ significantly between the two groups. However, the peri-induction warming group exhibited significantly less change in core temperature (0.61 ± 0.3 °C vs. 0.93 ± 0.4 °C, p = 0.002) and a slower core temperature drop rate (0.009 ± 0.005 °C/min vs. 0.013 ± 0.004 °C/min, p = 0.013) than the control group. The peri-induction warming group also reported higher thermal comfort scores (p = 0.041) and less need for postoperative warming (p = 0.034) compared to the control group. Conclusions: Brief peri-induction warming combined with warmed intravenous fluid was insufficient to prevent intraoperative hypothermia in patients undergoing urologic surgery. However, it improved patient thermal comfort and mitigated the absolute amount and rate of temperature drop.

Beyond day and night: The importance of ultradian rhythms in mouse physiology.

Our circadian world shapes much of metabolic physiology. In mice ∼40% of the light and ∼80% of the dark phase time is characterized by bouts of increased energy expenditure (EE). These ultradian bouts have a higher body temperature (Tb) and thermal conductance and contain virtually all of the physical activity and awake time. Bout status is a better classifier of mouse physiology than photoperiod, with ultradian bouts superimposed on top of the circadian light/dark cycle. We suggest that the primary driver of ultradian bouts is a brain-initiated transition to a higher defended Tb of the active/awake state. Increased energy expenditure from brown adipose tissue, physical activity, and cardiac work combine to raise Tb from the lower defended Tb of the resting/sleeping state. Thus, unlike humans, much of mouse metabolic physiology is episodic with large ultradian increases in EE and Tb that correlate with the active/awake state and are poorly aligned with circadian cycling.

Sleeping for One Week on a Temperature-Controlled Mattress Cover Improves Sleep and Cardiovascular Recovery.

Body temperature should be tightly regulated for optimal sleep. However, various extrinsic and intrinsic factors can alter body temperature during sleep. In a free-living study, we examined how sleep and cardiovascular health metrics were affected by sleeping for one week with (Pod ON) vs. without (Pod OFF), an active temperature-controlled mattress cover (the Eight Sleep Pod). A total of 54 subjects wore a home sleep test device (HST) for eight nights: four nights each with Pod ON and OFF (>300 total HST nights). Nightly sleeping heart rate (HR) and heart rate variability (HRV) were collected. Compared to Pod OFF, men and women sleeping at cooler temperatures in the first half of the night significantly improved deep (+14 min; +22% mean change; p = 0.003) and REM (+9 min; +25% mean change; p = 0.033) sleep, respectively. Men sleeping at warm temperatures in the second half of the night significantly improved light sleep (+23 min; +19% mean change; p = 0.023). Overall, sleeping HR (-2% mean change) and HRV (+7% mean change) significantly improved with Pod ON (p < 0.01). To our knowledge, this is the first study to show a continuously temperature-regulated bed surface can (1) significantly modify time spent in specific sleep stages in certain parts of the night, and (2) enhance cardiovascular recovery during sleep.

Process design and economic analysis for the production of microalgae from anaerobic digestates in open raceway ponds.

A model based framework was established for large scale assessment of microalgae production using anaerobically digested effluent considering varied climatic parameters such as solar irradiance and air temperature. The aim of this research was to identify the optimum monthly average culture depth operation to minimize the cost of producing microalgae grown on anaerobic digestion effluents rich in ammoniacal nitrogen with concentration of 248 mg L-1. First, a productivity model combined with a thermal model was developed to simulate microalgae productivity in open raceway ponds as a function of climatic variables. Second, by combining the comprehensive open pond model with other harvesting equipment, the final techno economic model was developed to produce a microalgae product with 20 wt% biomass content and treated water with <1 mg L-1 ammoniacal nitrogen. The optimization approach on culture depth for outdoor open raceway ponds managed to reduce the cost of microalgae production grown in anaerobic digested wastewater up to 16 %, being a suitable solution for the production of low cost microalgae (1.7 AUD kg-1 dry weight) at possible scale of 1300 t dry weight microalgae yr-1.

Female thermal sensitivity and behaviour across the lifespan: A unique journey.

Women are a group of individuals that undergo unique anatomical, physiological and hormonal changes across the lifespan. For example, consider the impact of the menstrual cycle, pregnancy and menopause, all of which are accompanied by both short- and long-term effects on female body morphology (e.g., changes in breast size) and temperature regulation, heat tolerance, thermal sensitivity and comfort. However, empirical evidence on how skin thermal and wetness sensitivity might change across the lifespan of women, and the implications that this has for female-specific thermal behaviours, continues to be lacking. This paper is based on a symposium presentation given at Physiology 2023 in Harrogate, UK. It aims to review new evidence on anatomical and physiological mechanisms underpinning differences in skin thermal and wetness sensitivity amongst women varying in breast size and age, in addition to their role in driving female thermal behaviours. It is hoped that this brief overview will stimulate the development of testable hypotheses to increase our understanding of the behavioural thermal physiology of women across the lifespan and at a time of climate change.

The Orexin/Hypocretin System, the Peptidergic Regulator of Vigilance, Orchestrates Adaptation to Stress.

The orexin/hypocretin neuropeptide family has emerged as a focal point of neuroscientific research following the discovery that this family plays a crucial role in a variety of physiological and behavioral processes. These neuropeptides serve as powerful neuromodulators, intricately shaping autonomic, endocrine, and behavioral responses across species. Notably, they serve as master regulators of vigilance and stress responses; however, their roles in food intake, metabolism, and thermoregulation appear complementary and warrant further investigation. This narrative review provides a journey through the evolution of our understanding of the orexin system, from its initial discovery to the promising progress made in developing orexin derivatives. It goes beyond conventional boundaries, striving to synthesize the multifaceted activities of orexins. Special emphasis is placed on domains such as stress response, fear, anxiety, and learning, in which the authors have contributed to the literature with original publications. This paper also overviews the advancement of orexin pharmacology, which has already yielded some promising successes, particularly in the treatment of sleep disorders.

Bundle para regulação da temperatura corporal de recém-nascidos maiores de 34 semanas: construção e validação / Bundle for regulating the body temperature of newborns over 34 weeks: Construction and validation / Paquete para regular la temperatura corporal de recién nacidos de más de 34 semanas: construcción y validación

Objetivo: Descrever o processo de construção e validação de um bundle para promoção da regulação da temperatura corporal de recém-nascidos maiores de 34 semanas. Métodos: Pesquisa metodológica executada em três etapas: revisão de escopo, construção da primeira versão do bundle e validação de conteúdo realizada por 15 experts, sendo nove enfermeiros e seis médicos, selecionados conforme critérios adaptados de referencial na área. O índice de validade de conteúdo acima de 0,80 foi considerado aceitável para a concordância entre os experts sobre cada cuidado. Foram necessárias duas rodadas de avaliação para a confecção da versão final. Resultados: O bundle foi estruturado em cuidados: na sala de parto, no transporte e no alojamento conjunto, com total de 15 itens, todos com concordância acima de 0,90 após a segunda rodada de avaliação. Conclusão: O bundle elaborado foi considerado válido quanto ao conteúdo e estabelece cuidados baseados em evidências científicas de maneira padronizada e segura para a equipe de assistência ao parto.

Objective: Describe the process of building and validating a bundle to promote body temperature regulation in newborns over 34 weeks of age. Methods: This methodological research was carried out in three stages: a scoping review, construction of the first version of the bundle, and content validation by 15 experts, nine nurses and six physicians, selected according to criteria adapted from references in the field. A content validity index above 0.80 was considered acceptable for the agreement among the experts on each type of care. Two rounds of evaluation were required to produce the final version. Results: The bundle was structured into care in the delivery room, during transportation, and in the rooming- in unit, with a total of 15 items, all with agreement above 0.90 after the second round of evaluation. Conclusion: The bundle developed was considered valid in terms of content and establishes care based on scientific evidence in a standardized and safe way for the childbirth care team.

Objetivo: Describir el proceso de creación y validación de un paquete para promover la regulación de la temperatura corporal en recién nacidos de más de 34 semanas de edad. Métodos: Investigación metodológica realizada en tres etapas: una revisión del alcance, la construcción de la primera versión del paquete y la validación del contenido llevada a cabo por 15 expertos, nueve enfermeras y seis médicos, seleccionados según criterios adaptados a partir de referencias en la materia. Se consideró aceptable un índice de validez de contenido superior a 0,80 para el acuerdo entre los expertos sobre cada tipo de atención. Fueron necesarias dos rondas de evaluación para elaborar la versión final. Resultados: El paquete se estructuró en cuidados: en la sala de partos, durante el transporte y en la unidad de alojamiento, con un total de 15 ítems, todos ellos con una concordancia superior a 0,90 tras la segunda ronda de evaluación. Conclusión: El paquete se consideró válido en cuanto a su contenido y establece una atención basada en pruebas científicas de forma estandarizada y segura para el equipo de atención al parto.

Myotendinous Thermoregulation in National Level Sprinters after a Unilateral Fatigue Acute Bout-A Descriptive Study.

In the last decade there has been a growing interest in infrared thermography in the field of sports medicine in order to elucidate the mechanisms of thermoregulation. The aim of this study was to describe bilateral variations in skin temperature of the anterior thigh and patellar tendon in healthy athletes and to provide a model of baseline tendon and muscle thermoregulation in healthy sprinters following a unilateral isokinetic fatigue protocol. Fifteen healthy national-level sprinters (eleven men and four women), with at least 3 years of athletic training experience of 10-12 h/week and competing in national-level competitions, underwent unilateral isokinetic force testing and electrostimulation in which their body temperature was measured before, during, and after the protocol using an infrared thermographic camera. ANOVA detected a significant difference in the time × side interaction for patellar temperature changes (p ≤ 0.001) and a significant difference in the time/side interaction for quadriceps temperature changes (p ≤ 0.001). The thermal challenge produces homogeneous changes evident in quadriceps areas, but not homogeneous in tendon areas. These data show that metabolic and blood flow changes may depend on the physical and mechanical properties of each tissue. Future research could be conducted to evaluate the predictive value of neuromuscular fatigue in the patellar tendon and quadriceps after exercise in order to optimize post-exercise recovery strategies.

Comparison of Yersinia enterocolitica DNA Methylation at Ambient and Host Temperatures.

Pathogenic bacteria recognize environmental cues to vary gene expression for host adaptation. Moving from ambient to host temperature, Yersinia enterocolitica responds by immediately repressing flagella synthesis and inducing the virulence plasmid (pYV)-encoded type III secretion system. In contrast, shifting from host to ambient temperature requires 2.5 generations to restore motility, suggesting a link to the cell cycle. We hypothesized that differential DNA methylation contributes to temperature-regulated gene expression. We tested this hypothesis by comparing single-molecule real-time (SMRT) sequencing of Y. enterocolitica DNA from cells growing exponentially at 22 °C and 37 °C. The inter-pulse duration ratio rather than the traditional QV scoring was the kinetic metric to compare DNA from cells grown at each temperature. All 565 YenI restriction sites were fully methylated at both temperatures. Among the 27,118 DNA adenine methylase (Dam) sites, 42 had differential methylation patterns, while 17 remained unmethylated regardless of the temperature. A subset of the differentially methylated Dam sites localized to promoter regions of predicted regulatory genes including LysR-type and PadR-like transcriptional regulators and a cyclic-di-GMP phosphodiesterase. The unmethylated Dam sites localized with a bias to the replication terminus, suggesting they were protected from Dam methylase. No cytosine methylation was detected at Dcm sites.

Estratégias de termorregulação em recém-nascidos prematuros: uma revisão de escopo / Thermoregulation strategies in premature newborns: a scoping review / Estrategias de termorregulación en recién nacidos prematuros: una revisión de alcance

Objetivo: mapear as estratégias para o controle e regulação da temperatura corporal em recém-nascidos prematuros. Método: revisão de escopo sobre termorregulação do prematuro, orientada pelas recomendações do Instituto Joanna Briggs, desenvolvida em oito bases de informações eletrônica. A busca, síntese e análise dos resultados ocorreu em dezembro de 2022. Resultados: compuseram a revisão 15 estudos que foram agrupados em duas categorias: Fontes de calor e Uso de pacotes de medidas/bundle. Como estratégias para a manutenção da temperatura corporal do prematuro, destacam-se: temperatura adequada materna e do ambiente; envoltório plástico; touca dupla; panos aquecidos; aquecimento do ar no suporte respiratório; contato pele a pele; berços aquecidos e incubadoras. Evidenciou-se que os recursos conjugados foram mais efetivos do que quando usados isoladamente. Conclusão: os resultados da revisão de escopo apontaram para estratégias que podem ser utilizadas para mitigar os riscos de hipotermia em recém-nascidos prematuros(AU)

Objective: to map strategies for controlling and regulating body temperature in premature newborns. Method: scope review on premature thermoregulation, guided by the recommendations of the Joanna Briggs Institute, developed in eight electronic databases. The search, synthesis and analysis of the results took place in December 2022. Results: the review was made up of 15 studies, which were grouped into two categories: Heat sources and use of measurement packages/bundle. As strategies for maintaining the body temperature of preterm infants, the following stand out: adequate maternal and environmental temperature; plastic wrap; double bonnet; heated cloths; air heating in respiratory support; skin-to-skin contact; heated cribs and incubators. It was evident that the combined resources were more effective than when used separately. Conclusion: the scoping review results pointed to strategies that can be used to mitigate the risks of hypothermia in premature newborns(AU)

Objetivo: mapear estrategias para el control y regulación de la temperatura corporal en recién nacidos prematuros. Método: revisión de alcance sobre la termorregulación prematura, siguiendo las recomendaciones del Instituto Joanna Briggs, desarrollada en ocho bases de datos electrónicas. La búsqueda, la síntesis y el análisis de los resultados se llevaron a cabo en diciembre de 2022. Resultados: la revisión fue conformada de 15 estudios, agrupados en dos categorías: fuentes de calor y uso de paquetes de medidas/bundle. Como estrategias para mantener la temperatura corporal del prematuro se destacan: temperatura adecuada materna y ambiental; envoltura de plástico; gorro doble; paños tibios; calentamiento del aire en soporte respiratorio; contacto piel a piel; cunas calefaccionadas e incubadoras. Se evidenció que los recursos combinados fueron más efectivos que si usados de forma individual. Conclusión: los resultados de la revisión de alcance señalaron estrategias que pueden usarse para mitigar los riesgos de hipotermia en recién nacidos prematuros(AU)

Pattern Recognition with Temperature Regulation: A Single YSZ-Based Mixed Potential Sensor Classifies Multiple Mixtures of Isoprene, n-Propanol, and Acetone.

Gas sensors integrated with machine learning algorithms have aroused keen interest in pattern recognition, which ameliorates the drawback of poor selectivity on a sensor. Among various kinds of gas sensors, the yttria-stabilized zirconia (YSZ)-based mixed potential-type sensor possesses advantages of low cost, simple structure, high sensitivity, and superior stability. However, as the number of sensors increases, the increased power consumption and more complicated integration technology may impede their extensive application. Herein, we focus on the development of a single YSZ-based mixed potential sensor from sensing material to machine learning for effective detection and discrimination of unary, binary, and ternary gas mixtures. The sensor that is sensitive to isoprene, n-propanol, and acetone is manufactured with the MgSb2O6 sensing electrode prepared by a simple sol-gel method. Unique response patterns for specific gas mixtures could be generated with temperature regulation. We chose seven algorithm models to be separately trained for discrimination. In order to realize more accurate discrimination, we further discuss the selection of suitable feature parameters and its reasons. With temperature regulation coefficients which are easily available as feature input to model, a single sensor is verified to achieve elevated accuracy rates of 95 and 99% for the discrimination of seven gases (three unary gases, three binary gas mixtures, and one ternary gas mixture) and redefined six gas mixtures. This article provides a potential new approach via a mixed potential sensor instead of a sensor array that could provide a wide application prospect in the field of electronic nose and artificial olfaction.

Solar heating may explain extreme diel flight altitude changes in migrating birds.

Great reed warblers, Acrocephalus arundinaceus,1 and great snipes, Gallinago media,2 exhibit a diel cycle in flight altitudes-flying much higher during the day than the night-when performing migratory flights covering both night and day. One hypothesis proposed to explain this behavior is that the birds face additional heating by solar radiation during daytime and hence must climb to very high, and thus also very cold, altitudes to avoid overheating during daytime flights.1,2 Yet, solar heat gain in birds has been shown to drastically decrease with wind speed,3,4 and the quantitative heating effect by solar radiation on a bird flying with an airspeed of 10 m/s or more is unknown. We analyzed temperature data from multisensor data loggers (MDLs)5,6 placed without direct exposure to solar radiation on great reed warblers (the logger covered by feathers on the back) and great snipes (the logger on the leg, covered from the sun by the tail). We found that logger temperatures were significantly higher (5.9°C-8.8°C in great reed warblers and 4.8°C-5.4°C in great snipes) during the day than during the night in birds flying at the same altitudes (and thus also the same expected ambient air temperatures). These results strongly indicate that the heat balance of the flying birds is indeed affected by solar radiation, which is in accordance with the hypothesis that solar radiation is a key factor causing the remarkable diel cycles in flight altitude observed in these two long-distance migrant bird species.1,2.

Phase Change Microcapsule Composite Material with Intelligent Thermoregulation Function for Infrared Camouflage.

The infrared camouflage textile materials with soft and wear-resistant properties can effectively reduce the possibility of soldiers and military equipment being exposed to infrared detectors. In this paper, the infrared camouflage textile composites with intelligent temperature adjustment ability were prepared by different methods, using phase change microcapsule as the main raw material and high polymer polyurethane as the matrix, combining the two factors of temperature control and emissivity reduction. It was tested by differential scanning calorimeter, temperature change tester, infrared emissivity tester, and infrared imager. The results show that the temperature regulation effect of textile materials finished by coating method is better than dip rolling method, the temperature regulation ability and presentation effect are the best when the microcapsule content is 27%. When the bottom layer of infrared camouflage textile composite is 27% phase change microcapsule and the surface layer is 20% copper powder, its infrared emissivity in the band of 2-22 µm is 0.656, and the rate of heating and cooling is obviously slowed down. It has excellent heat storage and temperature regulation function, which can reduce the skin surface temperature by more than 6 °C and effectively reduce the infrared radiation. This study can provide reference for laboratory preparation and industrial production of infrared camouflage composite material. The infrared camouflage textile composite prepared are expected to be used in the field of military textiles.

Comparative effects of warming systems applied to different parts of the body on hypothermia in adults undergoing abdominal surgery: A systematic review and network meta-analysis of randomized controlled trials.

STUDY OBJECTIVE: The prevention of perioperative hypothermia after anesthesia induction is a critical concern in patients undergoing abdominal surgery. The effectiveness of various warming systems for preventing hypothermia and shivering when applied to specific areas of the body remains undetermined. DESIGN: Systematic review and network meta-analysis. SETTING: Operating room. INTERVENTION: Five electronic databases were searched, including only randomized control trials (RCTs) reporting the effects of warming systems applied to specific body sites on the intraoperative core temperature and postoperative risk of shivering in adults undergoing abdominal surgery. A multivariate random-effects network meta-analysis with a frequentist framework was implemented for data analysis. MEASUREMENTS: The primary outcome was the core body temperature 60 and 120 min after anesthesia induction for abdominal surgery. The secondary outcome was the incidence of postoperative shivering. RESULTS: This review comprised a total of 24 RCTs including 1119 patients. At 60 and 120 min after anesthesia induction, a forced-air warming system applied to the upper body (0.3 °C and 95% confidence intervals = [0.3 to 0.4], 1.0 °C [0.7 to 1.3]), lower body (0.4 °C [0.3 to 0.5], 0.9 °C [0.5 to 1.2]), and underbody (0.5 °C [0.5 to 0.6], 1.2 °C [0.9 to 1.6]) was superior to passive insulation in terms of core body temperature regulation. Compared with passive insulation, the forced-air warming system applied to the lower body (odds ratio = 0.06) or underbody (0.44) and the electric heating blanket to the lower body (0.02) or the whole body (0.07) significantly reduced the risk of shivering. CONCLUSIONS: The results of this NMA revealed that forced-air warming with an underbody blanket effectively elevates core body temperatures in 60 and 120 min after induction of anesthesia and prevents shivering in patients recovering from abdominal surgery.