Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.713
Filtrar
1.
Nature ; 583(7814): 109-114, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32528181

RESUMO

Hibernating mammals actively lower their body temperature to reduce energy expenditure when facing food scarcity1. This ability to induce a hypometabolic state has evoked great interest owing to its potential medical benefits2,3. Here we show that a hypothalamic neuronal circuit in rodents induces a long-lasting hypothermic and hypometabolic state similar to hibernation. In this state, although body temperature and levels of oxygen consumption are kept very low, the ability to regulate metabolism still remains functional, as in hibernation4. There was no obvious damage to tissues and organs or abnormalities in behaviour after recovery from this state. Our findings could enable the development of a method to induce a hibernation-like state, which would have potential applications in non-hibernating mammalian species including humans.


Assuntos
Metabolismo Energético/fisiologia , Hibernação/fisiologia , Hipotálamo/citologia , Hipotálamo/fisiologia , Vias Neurais/citologia , Vias Neurais/fisiologia , Animais , Metabolismo Basal/fisiologia , Núcleo Hipotalâmico Dorsomedial/citologia , Núcleo Hipotalâmico Dorsomedial/fisiologia , Feminino , Neurônios GABAérgicos/metabolismo , Glutamina/metabolismo , Masculino , Camundongos , Consumo de Oxigênio/fisiologia
2.
J Sports Sci ; 38(14): 1635-1649, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32397898

RESUMO

The systematic review and meta-analysis evaluated the effect of aerobic, resistance and combined exercise on RMR (kCal·day-1) and performed a methodological assessment of indirect calorimetry protocols within the included studies. Subgroup analyses included energy/diet restriction and body composition changes. Randomized control trials (RCTs), quasi - RCTs and cohort trials featuring a physical activity intervention of any form and duration excluding single exercise bouts were included. Participant exclusions included medical conditions impacting upon RMR, the elderly (≥65 years of age) or pregnant, lactating or post-menopausal women. The review was registered in the International Prospective Register of Systematic Reviews (CRD 42,017,058,503). 1669 articles were identified; 22 were included in the qualitative analysis and 18 were meta-analysed. Exercise interventions (aerobic and resistance exercise combined) did not increase resting metabolic rate (mean difference (MD): 74.6 kCal·day-1[95% CI: -13.01, 161.33], P = 0.10). While there was no effect of aerobic exercise on RMR (MD: 81.65 kCal·day-1[95% CI: -57.81, 221.10], P = 0.25), resistance exercise increased RMR compared to controls (MD: 96.17 kCal·day-1[95% CI: 45.17, 147.16], P = 0.0002). This systematic review effectively synthesises the effect of exercise interventions on RMR in comparison to controls; despite heterogenous methodologies and high risk of bias within included studies.


Assuntos
Metabolismo Basal/fisiologia , Exercício Físico/fisiologia , Calorimetria Indireta , Humanos , Treinamento de Resistência
3.
Obesity (Silver Spring) ; 28(5): 902-906, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32320142

RESUMO

OBJECTIVE: The aim of this study was to investigate whether baseline (pre-weight loss) metabolic variables can predict weight regain. METHODS: About 117 women with overweight completed a weight loss program to achieve BMI < 25 kg/m2 and were followed for 2 years. Resting metabolic rate, respiratory quotient, insulin sensitivity, and serum leptin concentration were measured pre-weight loss, while on energy balance, and as predictors of weight regain at 1 and 2 years. Rate and amount of weight loss also were examined as predictors, as these outcomes may reflect metabolic phenotype. RESULTS: Average weight loss was 12 (SD 2.5) kg, and regain was 48% (SD 35%) and 80% (SD 52%) at 1 and 2 years, respectively. In regression modeling, metabolic variables (both pre-weight loss and changes with weight loss) did not predict weight regain. However, initial weight loss and time to achieve BMI < 25 were significant predictors of weight regain at 1 and 2 years, even after adjusting for confounders. CONCLUSIONS: Baseline (pre-weight loss) resting metabolic rate, respiratory quotient, insulin sensitivity, and leptin did not predict weight regain. However, a larger and faster weight loss was associated with a lower weight regain. Understanding the mechanisms behind interindividual variation in magnitude and rate of weight loss is needed to ensure better weight loss maintenance.


Assuntos
Metabolismo Basal/fisiologia , Obesidade/metabolismo , Ganho de Peso/fisiologia , Adulto , Feminino , Humanos , Masculino , Pré-Menopausa , Adulto Jovem
4.
Physiol Biochem Zool ; 93(2): 90-96, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32011970

RESUMO

Oxidative stress, the imbalance of reactive oxygen species and antioxidant capacity, may cause damage to biomolecules pivotal for cellular processes (e.g., DNA). This may impair physiological performance and, therefore, drive life-history variation and aging rate. Because aerobic metabolism is supposed to be the main source of such oxidative risk, the rate of oxygen consumption should be positively associated with the level of damage and/or antioxidants. Empirical support for such relationships remains unclear, and recent considerations suggest even a negative relationship between metabolic rate and oxidative stress. We investigated the relationship between standard metabolic rate (SMR), antioxidants, and damage in blood plasma and erythrocytes for 35 grass snakes (Natrix natrix). Reactive oxygen metabolites (dROMs) and nonenzymatic antioxidants were assessed in plasma, while two measures of DNA damage and the capacity to neutralize H2O2 were measured in erythrocytes. Plasma antioxidants showed no correlation to SMR, and the level of dROMs was positively related to SMR. A negative relationship between antioxidant capacity and SMR was found in erythrocytes, but no association of SMR with either measure of DNA damage was detected. No increase in DNA damage, despite lower antioxidant capacity at high SMR, indicates an upregulation in other defense mechanisms (e.g., damage repair and/or removal). Indeed, we observed a higher frequency of immature red blood cells in individuals with higher SMR, which indicates that highly metabolic individuals had increased erythrocyte turnover, a mechanism of damage removal. Such DNA protection through upregulated cellular turnover might explain the negligible senescence observed in some ectotherm taxa.


Assuntos
Metabolismo Basal/fisiologia , Colubridae/fisiologia , Dano ao DNA , Envelhecimento , Animais , Antioxidantes/análise , Colubridae/metabolismo , Eritrócitos/citologia , Eritrócitos/metabolismo , Feminino , Peróxido de Hidrogênio/metabolismo , Masculino , Estresse Oxidativo/fisiologia , Plasma/metabolismo , Espécies Reativas de Oxigênio/sangue
5.
Physiol Biochem Zool ; 93(2): 140-152, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32027231

RESUMO

Adaptive plasticity in avian thermal physiology is increasingly apparent, with a well-studied example being metabolic upregulation during cold winters in small birds inhabiting temperate and boreal latitudes. Recent studies have revealed greater variation in the direction and magnitude of seasonal metabolic adjustments among subtropical/tropical birds experiencing milder winters compared with higher-latitude counterparts, suggesting that patterns could vary among years within populations. We quantified seasonal metabolic variation (summer vs. winter) in Kalahari Desert populations of two Afrotropical passerines, the white-browed sparrow-weaver (WBSW; Plocepasser mahali; ∼40 g) and the scaly-feathered weaver (SFW; Sporopipes squamifrons; ∼10 g) over subsequent years (2014-2017). We used flow-through respirometry to measure basal metabolic rate (BMR) and summit metabolism (Msum; maximum cold-induced resting metabolic rate) and quantified seasonal fluctuations in air temperature (Ta) and food abundance (arthropod and grass seed abundance) at the study site. Our data reveal that the direction and magnitude of seasonal metabolic acclimatization vary among years in both species, with the winter BMR of WBSWs ranging from ∼20% lower to 68% higher compared with the summer BMR. In contrast to higher-latitude species, Msum was not related to the cold-limit temperature of birds or to winter minimum Ta at the study site, but interannual variation in BMR and Msum was significantly lower in seasons with lower food abundance in both WBSWs and SFWs. Our data support the idea that patterns of seasonal acclimatization are more variable in birds from lower latitudes and that there is considerable phenotypic flexibility in avian thermal physiology.


Assuntos
Aclimatação/fisiologia , Passeriformes/metabolismo , Estações do Ano , Adaptação Fisiológica , Animais , Artrópodes , Metabolismo Basal/fisiologia , Clima Desértico , Poaceae , África do Sul
6.
Appl Ergon ; 82: 102956, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31542574

RESUMO

Use of cold-weather personal protective clothing (PPC) in cold climates is essential but can add metabolic cost to the wearer. This study measured the effect of wearing state-of-the-art PPC and personal protective equipment (PPE), with the possible effect of clothing layers and fit, on physiological responses including metabolic rate (MR) and muscle activation level. 19 male participants (80.2 ±â€¯5.9 kg, 181.5 ±â€¯5.1 cm) wore five different clothing ensembles during level (0°) and inclined (6°) walking. Compared to a base layer ensemble (388.7 ±â€¯42.7 W/737.8 ±â€¯57.9 W), wearing a 3-layer PPC ensemble (421.5 ±â€¯44.7 W/811.7 ±â€¯69.2 W) significantly increased MR, and adding PPE (458.3 ±â€¯59.8 W/864.5 ±â€¯71.2 W) further increased MR during level/inclined walking. Independent of the extra weight, adding a middle layer between base layer and outer clothing significantly increased MR during inclined walking only, and no effect of oversized outer clothing was measured.


Assuntos
Metabolismo Basal/fisiologia , Temperatura Baixa , Músculo Esquelético/fisiologia , Roupa de Proteção , Caminhada/fisiologia , Eletromiografia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Noruega , Consumo de Oxigênio/fisiologia , Adulto Jovem
7.
Proc Natl Acad Sci U S A ; 116(43): 21609-21615, 2019 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-31570585

RESUMO

Climate change threatens global biodiversity by increasing extinction risk, yet few studies have uncovered a physiological basis of climate-driven species declines. Maintaining a stable body temperature is a fundamental requirement for homeothermic animals, and water is a vital resource that facilitates thermoregulation through evaporative cooling, especially in hot environments. Here, we explore the potential for thermoregulatory costs to underlie the community collapse of birds in the Mojave Desert over the past century in response to climate change. The probability of persistence was lowest for species occupying the warmest and driest sites, which imposed the greatest cooling costs. We developed a general model of heat flux to evaluate whether water requirements for evaporative cooling contributed to species' declines by simulating thermoregulatory costs in the Mojave Desert for 50 bird species representing the range of observed declines. Bird species' declines were positively associated with climate-driven increases in water requirements for evaporative cooling and exacerbated by large body size, especially for species with animal-based diets. Species exhibiting reductions in body size across their range saved up to 14% in cooling costs and experienced less decline than species without size reductions, suggesting total cooling costs as a mechanism underlying Bergmann's rule. Reductions in body size, however, are unlikely to offset the 50 to 78% increase in cooling costs threatening desert birds from future climate change. As climate change spreads warm, dry conditions across the planet, water requirements are increasingly likely to drive population declines, providing a physiological basis for climate-driven extinctions.


Assuntos
Aves/fisiologia , Regulação da Temperatura Corporal/fisiologia , Mudança Climática , Extinção Biológica , Animais , Metabolismo Basal/fisiologia , Aves/classificação , Tamanho Corporal/fisiologia , Temperatura Corporal/fisiologia , Clima Desértico , Estados Unidos , Água/análise
8.
Rev. andal. med. deporte ; 12(3): 272-277, sept. 2019. tab, graf
Artigo em Espanhol | IBECS | ID: ibc-191864

RESUMO

El objetivo de esta revisión fue analizar los estudios que investigaron los efectos del ejercicio aeróbico y de fuerza sobre la tasa metabólica en reposo como medios para el control del sobrepeso y de la obesidad. Se realizó una búsqueda electrónica en las principales bases de datos y se revisaron las citas de los artículos identificados en la búsqueda electrónica. Los efectos crónicos del entrenamiento aeróbico sobre la tasa metabólica en reposo parecen limitados; sin embargo, parece que la combinación de volumen e intensidad de ejercicio junto con el tiempo de entrenamiento produce efectos agudos sobre la misma. El entrenamiento de fuerza está asociado al incremento de masa muscular que puede generar un incremento de la tasa metabólica en reposo a largo plazo. Son necesarios más estudios para evaluar la asociación del entrenamiento de la fuerza y entrenamiento aeróbico, así como su impacto sobre la tasa metabólica en reposo, tanto de forma aguda como crónica


The objective of this review was to analyze the studies that investigated about the effects of aerobic and strength exercise in resting metabolic rate as a means to control overweight and obesity. The main electronic databases were used to search for articles and it were reviewed the references of the main articles identified in the electronic search. The chronic effects of aerobic training on resting metabolic rate appear limited; however, it seems that the combination of volume and intensity of exercise and duration of training produces acute effects on it. Strength training is associated with an increase in muscle mass that can lead to a chronic increase in resting metabolic rate. More studies are needed to evaluate the association of aerobic training and strength training, and its impact on resting metabolic rate, both acutely and chronically


O objetivo desta revisão foi analisar os estudos que investigaram os efeitos do exercício aeróbico e de força na taxa metabólica de repouso com aplicações no controle do sobrepeso e obesidade. As fontes utilizadas para localizar os artigos foram: busca eletrônica nas principais bases de dados e citações em artigos identificados na busca eletrônica. Os resultados obtidos sobre a taxa metabólica de repouso decorrente do treinamento aeróbico de forma crônica são limitados, porém, existem indícios que a combinação de volume e intensidade do exercício e tempo de treinamento podem produzir efeito agudo na mesma. Já o treinamento de força normalmente produz um aumento da massa muscular e com possibilidade de gerar um aumento na taxa metabólica de repouso a longo prazo. São necessários mais estudos para avaliar a associação do treinamento de força e aeróbico e seu impacto sobre a taxa metabólica de repouso, tanto de forma aguda como crônica


Assuntos
Humanos , Masculino , Feminino , Metabolismo Basal/fisiologia , Exercício Físico/fisiologia , Obesidade/fisiopatologia , Obesidade/metabolismo
9.
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
10.
J Endocrinol Invest ; 42(12): 1497-1507, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31359403

RESUMO

PURPOSE: The effect of combined lifestyle interventions (LSI) including dietary and physical activity on metabolic health, energy metabolism and VO2max in diabetic patients has provided mixed results. We evaluated the impact of 1-year caloric restriction (CR), and 12-week supervised structured exercise training (SSET) on metabolic health, RMR and VO2max in obese adults with type 2 diabetes. METHODS: After 1-month education for LSI, 33 participants had anthropometric, biochemical and metabolic assessments. They then started CR based on RMR, and 3-month SSET during the months 1-3 (Early-SSET) or 4-6 (Late-SSET). Reassessments were planned after 3, 6 and 12 months. Using a per-protocol analysis, we evaluated parameter changes from baseline and their associations for the 23 participants (11 Early-SSET, 12 Late-SSET) who completed the study. RMR was adjusted (adjRMR) for age, sex, fat-free mass (FFM) and fat mass (FM). RESULTS: Compared with baseline, after 6 months we found significant increases in VO2max (+ 14%) and HDL-cholesterol (+ 13%), and reduction in body mass index (- 3%), FM (- 8%) and glycated hemoglobin (HbA1c, - 7%). Training-related caloric expenditure negatively correlated with changes in body weight (p < 0.001), FM (p < 0.001) and HbA1c (p = 0.006). These results were confirmed at the 12-month follow-up. Pooling together all follow-up data, adjRMR changes correlated with changes in glycemia (r = 0.29, p = 0.02), total-cholesterol (r = 0.29, p = 0.02) and VO2max (r = - 0.26,p = 0.02). No significant differences emerged between the Early- and Late-SSET groups. CONCLUSIONS: Combined intervention with SSET and CR improved metabolic control. Changes in metabolic health and fitness correlated with changes of adjRMR, which was reduced improving fitness, glycemia and cholesterolemia. CLINICAL TRIAL REGISTRY: Trial registration number: NCT03785379. URL of registration: http://clinicaltrials.gov .


Assuntos
Metabolismo Basal/fisiologia , Restrição Calórica , Diabetes Mellitus Tipo 2/terapia , Metabolismo Energético/fisiologia , Terapia por Exercício , Obesidade/terapia , Peso Corporal , Diabetes Mellitus Tipo 2/dietoterapia , Diabetes Mellitus Tipo 2/metabolismo , Dieta Redutora , Feminino , Humanos , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Obesidade/dietoterapia , Obesidade/metabolismo
11.
Nutr Clin Pract ; 34(6): 922-934, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31347209

RESUMO

BACKGROUND: Our purpose was to assess the accuracy of resting energy expenditure (REE) equations in patients with newly diagnosed stage I-IV non-small cell lung, rectal, colon, renal, or pancreatic cancer. METHODS: In this cross-sectional study, REE was measured using indirect calorimetry and compared with 23 equations. Agreement between measured and predicted REE was assessed via paired t-tests, Bland-Altman analysis, and percent of estimations ≤ 10% of measured values. Accuracy was measured among subgroups of body mass index (BMI), stage (I-III vs IV), and cancer type (lung, rectal, and colon) categories. Fat mass (FM) and fat-free mass (FFM) were assessed using dual x-ray absorptiometry. RESULTS: Among 125 patients, most had lung, colon, or rectal cancer (92%, BMI: 27.5 ± 5.6 kg/m2 , age: 61 ± 11 years, REE: 1629 ± 321 kcal/d). Thirteen (56.5%) equations yielded REE values different than measured (P < 0.05). Limits of agreement were wide for all equations, with Mifflin-St. Jeor equation having the smallest limits of agreement, -21.7% to 11.3% (-394 to 203 kcal/d). Equations with FFM were not more accurate except for one equation (Huang with body composition; bias, limits of agreement: -0.3 ± 11.3% vs without body composition: 2.3 ± 10.1%, P < 0.001). Bias in body composition equations was consistently positively correlated with age and frequently negatively correlated with FM. Bias and limits of agreement were similar among subgroups of patients. CONCLUSION: REE cannot be accurately predicted on an individual level, and bias relates to age and FM.


Assuntos
Metabolismo Basal/fisiologia , Neoplasias/metabolismo , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Antropometria , Composição Corporal/fisiologia , Índice de Massa Corporal , Calorimetria Indireta , Estudos Transversais , Ingestão de Energia , Metabolismo Energético/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Estadiamento de Neoplasias , Neoplasias/patologia , Valor Preditivo dos Testes
12.
Cent Eur J Public Health ; 27(2): 135-140, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31241289

RESUMO

OBJECTIVE: Basal metabolic rate (BMR) is the main part of the total body energy expenditure. The value of BMR is individual and depends on a lot of factors. The goal of the research was to discover the influence of anthropometric parameters, age and gender, on changes of the BMR values. METHODS: A total of 177 individuals of Czech Caucasian origin from South Moravia (BMI 27.3 ± 7.88 kg/m2) aged 18-55 (117 women, 60 men) were included in the study. Selected anthropometric characteristics were measured using a stadiometer (SECA 213) and bioelectrical impedance analysis (Inbody 230). BMR was measured by indirect calorimetry (Cortex Metalyzer 3B). The measured values were statistically evaluated by the regression analysis and least square method (LSM). RESULTS: From the following results that the factors that influence the BMR value statistically significantly (p < 0.05) are: age, gender, body mass index, total body water, and percent of body fat. CONCLUSION: Body fat and age have both an indirect impact on the basal metabolic rate of the Czech population in working age. However, BMI and the total body water were discovered to have a direct influence on the BMR.


Assuntos
Metabolismo Basal/fisiologia , Composição Corporal/fisiologia , Metabolismo Energético , Adolescente , Adulto , Idoso , Antropometria , Calorimetria Indireta , República Tcheca , Impedância Elétrica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
13.
Bioessays ; 41(8): e1900033, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31210380

RESUMO

Unlike birds and mammals, reptiles are commonly thought to possess only the most rudimentary means of interacting with their environments, reflexively responding to sensory information to the near exclusion of higher cognitive function. However, reptilian brains, though structurally somewhat different from those of mammals and birds, use many of the same cellular and molecular processes to support complex behaviors in homologous brain regions. Here, the neurological mechanisms supporting reptilian cognition are reviewed, focusing specifically on spatial cognition and the hippocampus. These processes are compared to those seen in mammals and birds within an ecologically and evolutionarily relevant context. By viewing reptilian cognition through an integrative framework, a more robust understanding of reptile cognition is gleaned. Doing so yields a broader view of the evolutionarily conserved molecular and cellular mechanisms that underlie cognitive function and a better understanding of the factors that led to the evolution of complex cognition.


Assuntos
Evolução Biológica , Cognição/fisiologia , Répteis/fisiologia , Comportamento Espacial/fisiologia , Animais , Metabolismo Basal/fisiologia , Aves , Hipocampo/fisiologia , Mamíferos , Motivação/fisiologia , Neurogênese/fisiologia , Consumo de Oxigênio/fisiologia , Filogenia , Memória Espacial/fisiologia
14.
Nutr Health ; 25(3): 217-224, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31204608

RESUMO

BACKGROUND: There are different equations for estimating Resting Energy Expenditure (REE). However, these equations were mainly developed based on populations of western countries. AIM: The present study was conducted to determine the validity of REE predictive equations in adults with central obesity. METHODS: This study was conducted with 129 adults with central obesity aged 35-65 years, a sub-sample from a large cohort study (Western Iran), Kurdish population. REE was measured by indirect calorimetry (IC) and REE predictive equations. Data were analysed using Pearson correlation, paired t-test, concordance correlation coefficient (CCC), mean squared deviation (MSD), level of agreement (LOA) and Bland-Altman plot. RESULTS: All REE predictive equations had low CCC and high LOA. Although there was no statistically significant difference in the REE measured with IC and the REE predicted with the Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU), FAO/WHO/UNU (Height), Muller and revised Harris-Benedict equations (P = 0.874, 0.113, 0.619, 0.143 and P = 0.121), other equations had statistically significant differences with IC (P<0.001). In addition, the highest correlation was found between the IC (r = 0.682). The least difference was related to the FAO/WHO/UNU equation, with an agreement limit of -507.96 to 500.79 Kcal/day, with a 95% confidence interval. CONCLUSIONS: The results of this study showed that the FAO/WHO/UNU, Muller, revised Harris-Benedict equations and Mifflin St Jeor equations are relatively acceptable for estimating REE. However, these prediction equations are not good at predicting REE; more precise equations are needed to apply for different ethnic groups.


Assuntos
Metabolismo Basal/fisiologia , Obesidade Abdominal/fisiopatologia , Adulto , Idoso , Calorimetria Indireta/métodos , Estudos de Coortes , Estudos Transversais , Feminino , Humanos , Irã (Geográfico) , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Inquéritos e Questionários
15.
Clin Nutr ESPEN ; 32: 158-164, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31221282

RESUMO

OBJECTIVES: To measure basal metabolic rate (BMR) and to compare it with the values obtained from predictive equations in a sample of elderly (≥60 y) women. DESIGN: Cross-sectional study. PARTICIPANTS AND SETTING: Seventy-nine women living in Niterói, Rio de Janeiro, Brazil enrolled in physical activity programs open to the community. MEASUREMENTS: Anthropometric measures were obtained using standard procedures. Percent body fat (PBF) was assessed by DXA. BMR was measured (BMRm) by indirect calorimetry under standardized conditions and compared with BMR estimated by 14 predictive equations that included elderly individuals in their development. RESULTS: Mean (±SD) age, BMI and PBF were 69.7 ± 6.5 y, 27.2 ± 4.6 kg/m2 and 42.1 ± 5.9%. BMRm (4188.3 ± 707.2 kJ/day) was significantly lower than estimated BMR by all predictive equations, including the equation developed for the Niteroian adult population (4565.6 ± 607.9 kJ/day). This population-specific equation provided the largest number of results within ±10% of BMRm and the lowest overestimation (10.6 ± 15.4%), much lower than the results from the internationally recommended Schofield equation (27.2 ± 17.6%). Regression of calf circumference (CC), age and body mass on BMRm provided similar estimates in comparison to models with fat-free mass (FFM). CONCLUSIONS: All predictive equations provided biased, inaccurate estimates of BMR values in comparison to BMRm. Anthropometry and body composition explained only approximately 50% of the variability of BMRm. New equations should account for the variability of organ-metabolic rates and underlying undetected health conditions in older individuals living in tropical regions.


Assuntos
Metabolismo Basal/fisiologia , Idoso , Idoso de 80 Anos ou mais , Antropometria , Composição Corporal , Índice de Massa Corporal , Brasil , Calorimetria Indireta/normas , Estudos Transversais , Feminino , Humanos , Pessoa de Meia-Idade , Valores de Referência , Reprodutibilidade dos Testes , População Urbana
16.
J Nutr Sci Vitaminol (Tokyo) ; 65(2): 148-156, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31061283

RESUMO

Malnutrition is a severe problem among elderly residents living in long-term care facilities. A simple and accurate estimation for total daily energy expenditure (TEE) is required in order to provide them with an adequate amount of food. The purpose of this study was to validate a physical activity assessment tool for estimating TEE among elderly residents. The data of 58 subjects aged 69-99 y were analyzed in this study. The one-day physical activity recall was filled out by facility staff for a typical day. TEE was measured by the doubly labeled water (DLW) method (TEEDLW), and predicted by one-day physical activity recall using the basal metabolic rate (pTEEBMR) and body weight (pTEEBW). The TEEDLW, pTEEBMR and pTEEBW were 1,129±196 kcal/d, 1,186±251 kcal/d and 1,326±236 kcal/d, respectively. In a regression model, body weight, movement means and sex explained 39.0% of the variance in the difference between pTEEBMR and TEEDLW (p<0.05). Percentage of fat mass, body weight, and Barthel Index except mobility explained 47.3% of the variance in the difference between pTEEBW and TEEDLW (p<0.05). The current results suggested that pTEEBW is not recommended to estimate TEE because the error depends on body size, and pTEEBMR was significantly correlated with TEEDLW but also included systematic errors in elderly residents. In order to improve the accuracy of the present assessment to estimate TEE, it is necessary to establish a new equation of basal metabolic rate for elderly residents and consider sex and movement means to estimate TEE.


Assuntos
Metabolismo Energético/fisiologia , Exercício Físico/fisiologia , Assistência de Longa Duração , Idoso , Idoso de 80 Anos ou mais , Antropometria/métodos , Metabolismo Basal/fisiologia , Peso Corporal/fisiologia , Estudos Transversais , Coleta de Dados/normas , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes
17.
Nutrients ; 11(5)2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-31071956

RESUMO

Addressing malnutrition is important to improve health outcomes in outpatients with cirrhosis, yet assessing energy requirements in this population is challenging. Predictive equations of resting energy expenditure (REE) are thought to be unreliable, and traditional indirect calorimetry is expensive and infrequently available for clinical use. The accuracy of REE predictions using a MedGem® handheld indirect calorimeter, the Harris Benedict Equation (HBE), the Mifflin St. Jeor equation (MSJ), and the gold standard Vmax Encore® (Vmax) metabolic cart was compared. The REE of cirrhotic pre-liver transplant outpatients was analyzed using each of the four methods. Agreement between methods was calculated using Bland-Altman analysis. Fourteen patients with cirrhosis participated, and were primarily male (71%) and malnourished (subjective global assessment (SGA) B or C 64%). Lin's concordance coefficient (ρC) for MedGem® vs. Vmax demonstrated poor levels of precision and accuracy (ρC = 0.80, 95% confidence interval 0.55-0.92) between measures, as did the HBE compared to Vmax (ρC = 0.56, 95% confidence interval 0.19-0.79). Mean REE by MedGem® was similar to that measured by Vmax (-1.5%); however, only 21% of REE measures by MedGem® were within ±5% of Vmax measures. Wide variability limits the use of MedGem® at an individual level; a more accurate and feasible method for determination of REE in patients with cirrhosis and malnutrition is needed.


Assuntos
Calorimetria Indireta/instrumentação , Calorimetria Indireta/métodos , Cirrose Hepática/metabolismo , Adulto , Metabolismo Basal/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pacientes Ambulatoriais
18.
J Fish Biol ; 95(2): 638-641, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31095737

RESUMO

The effects of structural enrichment in the hatchery rearing environment of brown trout Salmo trutta was linked to post-release performance. Enrichment resulted in reduced swimming activity scored in an open field test and reduced movement in a natural river after release. Also, enrichment increased resting metabolic rates, which correlated positively with overwinter growth.


Assuntos
Metabolismo Basal/fisiologia , Pesqueiros , Truta/fisiologia , Animais , Metabolismo Energético/fisiologia , Respiração , Rios , Suécia , Natação , Temperatura , Truta/crescimento & desenvolvimento , Truta/metabolismo
19.
Mol Metab ; 25: 168-176, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31003945

RESUMO

OBJECTIVES: Ambient temperature impinges on energy metabolism in a body size dependent manner. This has implications for the housing temperature at which mice are best compared to humans. In 2013, we suggested that, for comparative studies, solitary mice are best housed at 23-25 °C, because this is 3-5 °C below the mouse thermoneutral zone and humans routinely live 3-5 °C below thermoneutrality, and because this generates a ratio of DEE to BMR of 1.6-1.9, mimicking the ratio found in free-living humans. METHODS: Recently, Fischer et al. (2017) challenged this estimate. By studying mice at 21 °C and at 30 °C (but notably not at 23-25 °C) they concluded that 30 °C is the optimal housing temperature. Here, we measured energy metabolism of C57BL/6 mice over a range of temperatures, between 21.4 °C and 30.2 °C. RESULTS: We observed a ratio of DEE to BMR of 1.7 at 27.6 °C and of 1.8 at 25.5 °C, suggesting that this is the best temperature range for housing C57BL/6 mice to mimic human thermal relations. We used a 24 min average to calculate the ratio, similar to that used in human studies, while the ratio calculated by Fisher et al. dependent on short, transient metabolic declines. CONCLUSION: We concur with Fisher et al. and others that 21 °C is too cool, but we continue to suggest that 30 °C is too warm. We support this with other data. Finally, to mimic living environments of all humans, and not just those in controlled Western environments, mouse experimentation at various temperatures is likely required.


Assuntos
Metabolismo Basal/fisiologia , Abrigo para Animais , Fisiologia Comparada , Temperatura , Animais , Tamanho Corporal , Dieta , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Consumo de Oxigênio
20.
Integr Comp Biol ; 59(4): 953-969, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30924869

RESUMO

As part of mitonuclear communication, retrograde and anterograde signaling helps maintain homeostasis under basal conditions. Basal conditions, however, vary across phylogeny. At the cell-level, some mitonuclear retrograde responses can be quantified by measuring the constitutive components of oxidative stress, the balance between reactive oxygen species (ROS) and antioxidants. ROS are metabolic by-products produced by the mitochondria that can damage macromolecules by structurally altering proteins and inducing mutations in DNA, among other processes. To combat accumulating damage, organisms have evolved endogenous antioxidants and can consume exogenous antioxidants to sequester ROS before they cause cellular damage. ROS are also considered to be regulated through a retrograde signaling cascade from the mitochondria to the nucleus. These cellular pathways may have implications at the whole-animal level as well. For example, birds have higher basal metabolic rates, higher blood glucose concentration, and longer lifespans than similar sized mammals, however, the literature is divergent on whether oxidative stress is higher in birds compared with mammals. Herein, we collected literature values for whole-animal metabolism of birds and mammals. Then, we collected cellular metabolic rate data from primary fibroblast cells isolated from birds and mammals and we collected blood from a phylogenetically diverse group of birds and mammals housed at zoos and measured several parameters of oxidative stress. Additionally, we reviewed the literature on basal-level oxidative stress parameters between mammals and birds. We found that mass-specific metabolic rates were higher in birds compared with mammals. Our laboratory results suggest that cellular basal metabolism, total antioxidant capacity, circulating lipid damage, and catalase activity were significantly lower in birds compared with mammals. We found no body-size correlation on cellular metabolism or oxidative stress. We also found that most oxidative stress parameters significantly correlate with increasing age in mammals, but not in birds; and that correlations with reported maximum lifespans show different results compared with correlations with known aged birds. Our literature review revealed that basal levels of oxidative stress measurements for birds were rare, which made it difficult to draw conclusions.


Assuntos
Metabolismo Basal/fisiologia , Aves/fisiologia , Fenômenos Fisiológicos Sanguíneos , Fibroblastos/metabolismo , Mamíferos/fisiologia , Estresse Oxidativo/fisiologia , Fatores Etários , Animais , Tamanho Corporal , Especificidade da Espécie
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA