[Calcification of basal metabolism].
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Basal Metabolism↗
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Predictive equations for basal metabolic rates of Indian males.
The article deals with the generation of a prediction equation for basal metabolic rate (BMR) of well-nourished Indian males, from prospective measurements on 121 males, using a single validated technique. The equation related BMR to simple measures such as weight (WT) and age, and was given by: BMR (kJ/d) = 48.7 * WT-14.1 * AGE + 3599. The equation was internally as well as externally validated against other Indian databases and the net differences of < 2% (100 kJ/d), were non-significant. Interestingly, American BMRs were predicted to within 0.5% (28 kJ/d) by this equation, while European BMRs were significantly higher than predicted by 6.3% (433 kJ/d). Similar results were obtained on validating the American and European data against the equations of C. K. J. Henry & D. G. Rees (1991) Eur J. Clin. Nutr. 45, 177-185. Such results suggest that there are no differences in the BMR of age- and weight-matched Asian Indian males, other tropical populations and Americans. This has implications in the estimation of energy expenditure and hence energy requirements for these populations.
Adolescent↗
Accuracy of equations to predict basal metabolic rate in older women.
OBJECTIVE: To assess the accuracy of several published equations for predicting basal metabolic rate (BMR) in older women. DESIGN: BMR was assessed in 116 healthy, older white women, aged 60 to 82 years, on three successive mornings by indirect calorimetry. Body composition was determined by dual energy X-ray absorptiometry or hydrostatic weighing. The measured BMRs were compared with values obtained from eight published prediction equations that used solely, or in various combinations, measures of height, weight, fat-free mass, age, and menopausal status. STATISTICAL ANALYSES PERFORMED: The root mean squared prediction error (RMSPE) was used to determine how accurately predicted BMR matched actual BMR for each subject. In addition, regression analysis was used to evaluate accuracy of predicted BMR vs directly measured BMR. RESULTS: Predicted mean BMR determined using all eight equations was significantly correlated to measured BMR (P = .0001), accounting for 30% to 52% of the variance of measured BMR. When analyzed by RMSPE, however, the equations of Owen et al (1986), Fredrix et al (1990), and Harris-Benedict (1919) predicted actual BMR for each subject within an average of 116 kcal/day, and the equation of Cunningham (1980) resulted in the largest prediction error at 208 kcal/day. APPLICATIONS/CONCLUSIONS: The regression equations of Owen et al (1986), which used body weight, Fredrix et al (1990), which used body weight and age, and Harris-Benedict (1919), which used age, weight, and height as variables, were most accurate in predicting BMR in our sample of healthy older women.
Absorptiometry, Photon↗
Effects of recombinant human growth hormone on basal metabolic rate in adults with pituitary deficiency.
The effect of recombinant human growth hormone (rhGH) on basal metabolic rate (BMR) was studied in a placebo-controlled, double-blind, crossover trial. Ten patients with a history of complete pituitary insufficiency were randomized for 26 weeks in each period. Three patients were excluded due to withdrawal, fever, and claustrophobia, respectively. All patients had received adrenal, thyroid, and gonadal substitution therapy for at least 1 year before the study. The dose of rhGH was 0.25 to 0.5 U/kg/wk, administered subcutaneously once a day in the evening. BMR was determined by indirect calorimetry in a computerized ventilated open-hood system. Body composition was examined using four different methods--computed tomography (CT), tritium dilution, 40K determinations, and total body nitrogen (TBN) measured with neutron activation. The body composition data have previously been reported. Fat-free mass (FFM) increased and body fat (BF) decreased during the first 6 weeks of rhGH treatment, but no further changes in body composition occurred between 6 and 26 weeks. Baseline BMRs in GH-deficient (GHD) patients were in the lower part of the reference range, but BMR and the ratio between BMR and FFM (BMR/FFM) were not significantly lower than in a carefully selected control group. BMR increased between 0 and 6 weeks (mean +/- SD: from 6.68 +/- 1.55 to 7.75 +/- 1.35 MJ/24 h, P < .001) and then remained unchanged between 6 and 26 weeks. The increase in BMR was closely related to the increase in FFM (r = .91, P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Predictive equations for basal metabolic rate in Chinese adults: a cross-validation study.
OBJECTIVE: To develop predictive equations for basal metabolic rate (BMR) in healthy Chinese adults and to evaluate factors that may influence BMR. DESIGN: Measuring the BMR of Chinese adults by indirect calorimetry. Selected subjects were randomly assigned to a validation sample and a cross-validation sample. The validation sample was used to develop predictive equations that were cross-validated using the other sample. SUBJECTS: Two hundred twenty-three healthy Chinese adults (102 men and 121 women) participated in the study. Their ages ranged from 20 to 78 years old (mean = 43.8 +/- 14.3 years). MEASURES: BMR was measured by indirect calorimetry. Body composition was assessed by skinfold fat thicknesses, bioelectrical impedance analysis, and urinary creatinine excretion. STATISTICAL ANALYSES PERFORMED: Student's t test, Pearson correlation coefficients, linear regression analyses, and the best subset were used for statistical analyses. RESULTS: The better-fitting equation for predicting BMR in Chinese adults is BMR = 13.88 x weight (kg) + 4.16 x height (cm) - 3.43 x age (years) - 112.40 x sex (men = 0; women = 1) +54.34. Men had higher BMR values than women because men had greater fat-free mass, body cell mass, and muscle mass. BMR correlated best with body composition, which correlated highly with anthropometric measurements. Therefore, accurate determination of body weight and body height are beneficial in predicting a person's BMR. All of the currently available predictive equations overestimated BMR (P = .0001) for healthy Chinese adults. The equations developed in this study predict BMR more accurately for Chinese adults. APPLICATIONS: The equations developed in this study are recommended for clinical use in healthy Chinese adults who are within normal limits for body weight.
Adult↗
The influence of climate on the basal metabolic rate of small mammals: a slow-fast metabolic continuum.
The influence of climate (mean annual rainfall, rainfall variability, ambient temperature, T(a)) on the basal metabolic rate (BMR) of 267 small mammals (<1 kg) from six zoogeographical zones was investigated using conventional and phylogenetically independent data (linear contrasts). All climate variables varied between zones, as did BMR and body temperature ( T(b)), but not thermal conductance. Holarctic zones were more seasonal and colder, but rainfall was less variable, than non-Holarctic zones. In general, the BMR was most strongly influenced by body mass, followed by T(a) and the rainfall variables. However, there was significant variation in the strength of these relationships between zones. BMR and T(b) increased with latitude, and mass-independent BMR and T(b) were positively correlated. The latter relationship offers evidence of a slow-fast metabolic continuum in small mammals. The fast end of the continuum (high BMR) is associated with the highest latitudes where BMR is most strongly influenced by T(a) and mean annual rainfall (i.e. mean productivity). The slow end of the continuum (low BMR) is associated with the semi-tropics, low productivity zones, and climatically unpredictable zones, such as deserts. Here rainfall variability has the strongest influence on BMR after body size. The implications of a slow-fast metabolic continuum are discussed in terms of various models associated with the evolution of BMR, such as the aerobic capacity models and the "energetic definition of fitness" models.
Acclimatization↗
Free serum thyroxine level and basal metabolic rate. Aids to diagnosis in malnutrition and small-for-gestational-age dwarfism.
Measurement of the basal metabolic rate (BMR) and the total and free serum thyroxine values in response to feeding are aids in the diagnosis of growth failure. Infants with small-for-gestational-age dwarfism gained weight poorly in the hospital, had a low BMR before and after spontaneous or induced weight gain, and a normal serum thyroxine value. Infants with linear growth failure due to chronic malnutrition had a normal BMR but a low serum thyroxine value that rose to normal with weight gain; infants with clinical signs of recent weight loss had a low BMR and a low serum thyroxine value, both of which rose to normal with weight gain. Increases of the BMR were sharp and very rapid; they preceded the rise of the serum thyroxine value in some cases.
Basal Metabolism↗
Basal metabolic rate in children with a solid tumour.
OBJECTIVE: To study the level of and changes in basal metabolic rate (BMR) in children with a solid tumour at diagnosis and during treatment in order to provide a more accurate estimate of energy requirements for nutritional support. DESIGN: An observational study. SETTING: Tertiary care at the Centre for Paediatric Oncology, University Hospital Nijmegen. SUBJECTS: Thirteen patients were recruited from a population of patients visiting the University Hospital Nijmegen for treatment. All patients asked to participate took part in and completed the study. INTERVENTION: BMR was measured by indirect calorimetry, under stringent, standardised conditions, for 20 min and on three different occasions in all patients. Continuous breath gas analysis using a mouthpiece was performed. Weight, height and skinfold measurements were performed before each measurement. MAIN OUTCOME MEASURES: BMR was expressed as percentage of the estimated reference value, according to the Schofield formulas based on age, weight and sex, and in kJ (kcal) per kg of fat-free mass. RESULTS: At diagnosis, the BMR was higher than the estimated reference BMR in all patients and 44% of the patients were considered hypermetabolic. Mean BMR (as percentage of reference) was significantly increased (11.6% (s.d. 6.7%); P=0.001), but decreased during treatment in 12 of the 13 patients (mean decrease 12.7% (s.d. 3.9%); P<0.0001). Furthermore, a significant negative correlation (P=-0.67; P=0.01) was found between the change in BMR and tumour response. CONCLUSIONS: These data suggest that the BMR of children with a solid tumour is increased at diagnosis and possibly during the first phase of oncologic treatment. This may be important when determining energy requirements for nutritional support.
Adolescent↗
The basal metabolic rate determination.
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Basal Metabolism↗
[Experimental studies on affective influences on basal metabolism].
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Basal Metabolism↗
Immune challenge affects basal metabolic activity in wintering great tits.
The costs of exploiting an organism's immune function are expected to form the basis of many life-history trade-offs. However, there has been debate about whether such costs can be paid in energetic and nutritional terms. We addressed this question in a study of wintering, free-living, male great tits by injecting them with a novel, non-pathogenic antigen (sheep red blood cells) and measuring the changes in their basal metabolic rates and various condition indices subsequent to immune challenge. The experiment showed that activation of the immune system altered the metabolic activity and profile of immune cells in birds during the week subsequent to antigen injection: individuals mounting an immune response had nearly 9% higher basal metabolic rates, 8% lower plasma albumin levels and 37% higher heterophile-to-lymphocyte ratios (leucocytic stress indices) than sham-injected control birds. They also lost nearly 3% (0.5 g) of their body mass subsequent to the immune challenge. Individuals that mounted stronger antibody responses lost more mass during the immune challenge. These results suggest that energetic expenditures to immune response may have a non-trivial impact upon an individual's condition.
Animals↗
[Effect of vitamin E on general metabolism and on thyroid function in subjects with normal and altered basal metabolism].
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Basal Metabolism↗
Testosterone influences basal metabolic rate in male house sparrows: a new cost of dominance signalling?
Sexually selected signals of individual dominance have profound effects on access to resources, mate choice and gene flow. However, why such signals should honestly reflect individual quality is poorly understood. Many such signals are known to develop under the influence of testosterone. We conducted an experiment in male house sparrows in which testosterone was manipulated independently during two periods: before the onset of the breeding season and prior to the autumn moult. We then measured the effects of these manipulations on basal metabolic rate and on the size of the chest bib, a sexually selected signal. The results demonstrate that testosterone simultaneously affects both signal development and basal metabolic rate in the house sparrow (Passer domesticus). This evidence, therefore, supports a novel conclusion: that testosterone-dependent signals act as honest indicators of male quality possibly because only high-quality individuals can sustain the energetic costs associated with signal development.
Animals↗
Predicting basal metabolic rate in the obese is difficult.
OBJECTIVE: To reassess the validity of the Schofield equations for predicting basal metabolic rate (BMR) in the obese. DATA: The data collection compiled from many studies by Schofield in 1985. METHODS: Nonparametric curve fitting and comparison of groups. RESULTS: BMR increases more slowly at heavier weights in men (above about 75 kg) and women (above about 65 kg), and to ignore this is to predict overestimates of BMR. Data obtained from studies of different populations show substantial differences, which are influential when data are combined. CONCLUSIONS: The Schofield equations are unsuitable for obese populations. Given that current Western populations exhibit prevalences of obesity many times greater than those in the Schofield database, this indicates the need for further study of suitable predictors for these individuals.
Adolescent↗
The influence of heat increment of feeding on basal metabolic rate in Phyllotis darwini (Muridae).
One of the most important prerequisites for obtaining a reliable measure of basal metabolic rate (BMR) in endotherms is that the animal must be in a post-absorptive condition. However, because of the diversity of nutrition and digestion modes in vertebrates, it is not simple to generalize a standard procedure for BMR measurement. Thus, information in this regard must be experimentally obtained by measuring the heat increment of feeding (HIF). We used a repeated-measures design to test for the effects of HIF on BMR in Phyllotis darwini, a granivorous rodent. Our results suggest that, in this species, feeding induces an elevation in O(2) consumption that can persist up to 4 h after the last meal. In addition, and irrespective of the fasting period, measures made with less than 2 h of fasting yield BMR values that are significantly higher than measurements after longer fasting periods (i.e. 3 and 4 h).
Animals↗
Basal metabolic rate and energy expenditure of pregnant Nigerian women.
The purpose of the present study was to compare basal metabolic rates (BMR) of pregnant Nigerian women from rural and urban areas with values from similar studies in other Third World countries. We also investigated possible changes in BMR during the course of pregnancy. An open-circuit indirect calorimeter was used to measure BMR and energy expenditure (EE) during sedentary activity in forty-one pregnant Nigerian women. The results showed marked variability in BMR among individuals. A correlation analysis between BMR and other biological and physical characteristics revealed bodyweight and gestation as the only variables related to BMR and oxygen consumption. The study revealed no significant difference between BMR and EE of sedentary activity in the subjects. The wide variability may have been due to the nutritional status of the subjects studied, who were drawn largely from the lower socioeconomic groups of Nigerian society. The present study shows that socioeconomic status and nutritional interventions should be taken into account when framing recommendations for maternal nutrition during pregnancy.
Adolescent↗
Basal metabolic rate and body fatness of adult men in northern Mexico.
To investigate the possibility that overprediction of basal metabolic rate (BMR) of tropical populations is related to differences in fatness between tropical and temperate populations, 32 Mexican men aged 18-40 years underwent measurements of BMR and body fat content. The men were divided into four body mass index (BMI) groups (< 20, 20-25, 25-30 and 30-40). The mean weight was 78 (range 52-119) kg and the mean height was 1.75 (range 1.61-1.89) m. BMR was measured in the subjects after an overnight stay in a residential unit by a Deltatrac ventilated hood indirect calorimetry system. Body fat content was determined by 2H2O dilution. The relationship between BMR and body weight was analysed by linear regression and the equations derived were compared to the values predicted using the FAO/WHO/UNU (1985) equations. The FAO/WHO/UNU equations overestimated measured BMR by 9.8%, 9.6%, 7.8% and 5.5% in the four groups. The overall difference was 8.2%, which was statistically significant (P < 0.001). The intercepts of the two equations were significantly different (P < 0.001) by 532 kJ/day, but there was no significant difference between the slopes of the two regression equations. There was no significant difference between BMR/kg fat-free mass in the four BMI groups. The results therefore do not support the possibility that the overprediction of BMR in tropical populations by international prediction equations based on body weight is accounted for by differences in fatness between tropical and temperate populations.
Adipose Tissue↗
A phylogenetic analysis of basal metabolism, total evaporative water loss, and life-history among foxes from desert and mesic regions.
We measured basal metabolic rate (BMR) and total evaporative water loss (TEWL) of species of foxes that exist on the Arabian Peninsula, Blanford's fox (Vulpes cana) and two subspecies of Red fox (Vulpes vulpes). Combining these data with that on other canids from the literature, we searched for specialization of physiological traits among desert foxes using both conventional least squares regression and regressions based on phylogenetic independent contrasts. Further, we explored the consequences of reduced body size of foxes on life history parameters such as litter size and neonate mass. For Blanford's foxes, Red foxes from the central desert of Arabia, and Red foxes from the more mesic Asir mountains, body mass averaged 1,285 +/- 52 g, 1,967 +/- 289 g, and 3,060 +/- 482 g, respectively, whereas mean BMR, during summer, was 304.5 +/- 32.3 kJ/day, 418.0 +/- 32.4 kJ/day, and 724.1 +/- 120.2 kJ/day (+/- SD). An analysis of covariance with body mass as a covariate showed no statistical differences in BMR among foxes. Analysis of covariance indicated that Red fox from the Asir mountains had a higher TEWL than Red foxes from central Arabia or than Blanford's foxes also from the mountains. Comparisons of all species of desert and mesic foxes showed no significant differences in BMR, nor did desert foxes have a significantly lower BMR than other carnivores. TEWL of desert foxes was lower than other more mesic carnivores; deviations in TEWL ranged from -17.7% for the Fennec fox (Fennecus zerda) to -57.4% for the Kit fox (Vulpes velox). Although desert foxes have a BMR comparable to other more mesic species, it appears that desert foxes do have a smaller body mass, lowering overall energy requirements. We attribute this reduction in body size to the "resource limitation hypothesis" whereby natural selection favors smaller individuals in a resource-limited environment, especially during periods of severe food shortage. However, until common garden experiments are performed, developmental plasticity and acclimation cannot be ruled out as contributors to this pattern.
Adaptation, Physiological↗