Multiples Of Basal Metabolic Rate Research Articles

Plausible self-reported dietary intakes in a residential facility are not necessarily reliable.

Comparing reported energy intakes with estimated energy requirements as multiples of basal metabolic rate (Ein:BMR) is an established method of identifying implausible food intake records. The present study aimed to examine the validity of self-reported food intakes believed to be plausible. One hundred and eighty men and women were provided with all food and beverages for two consecutive days in a residential laboratory setting. Subjects self-reported their food and beverage intakes using the weighed food diary method (WDR). Investigators covertly measured subjects' actual consumption over the same period. Subjects also reported intakes over four consecutive days at home. BMR was measured by indirect calorimetry. Average reported energy intakes were significantly lower than actual intakes (11.2 and 11.8 MJ/d, respectively, P<0.001). Two-thirds (121) of the WDR were under-reported to varying degrees. Only five of these were considered as implausible using an Ein:BMR cut-off value of 1.03*BMR. Under-reporting of food and beverage intakes, as measured by the difference between reported and actual intake, was evident at all levels of Ein;BMR. Reported energy intakes were lower still (10.2 MJ/d) while subjects were at home. Under-recording of self-reported food intake records was extensive but very few under-reported food intake records were identified as implausible using energy intake to BMR ratios. Under-recording was evident at all levels of energy intake.

Self-esteem Mediates Associations of Physical Activity with Anxiety in College Women

Why physically active people report lower anxiety than those who are inactive is not well understood. This study examined whether physical self-concept and self-esteem would mediate associations of self-reported physical activity with anxiety disorder symptoms in young women, a population with elevated risk for developing an anxiety disorder. College women (N = 1036, mean ± SD = 19.7 ± 2.9 yr) completed a physical activity recall, the Psychiatric Diagnostic Screening Questionnaire, and the Physical Self-Description Questionnaire. Structural equation modeling was used to test hypotheses. Physical activity had inverse, indirect associations with symptoms of social phobia, generalized anxiety disorder, and obsessive-compulsive disorder that were expressed through its positive association with specific and global physical self-concept and self-esteem. The results were independent of similar relations with symptoms of major depressive disorder as well as the estimates of body fatness and use of psychotropic medications. These correlational findings provide initial evidence to warrant experimental efficacy trials of whether physical activity will reduce the risk of anxiety disorders in young women by positive influences on physical self-concept and self-esteem.

Associations between sociodemographic and lifestyle factors and dietary quality among adolescents in Palma de Mallorca

We assessed associations between sociodemographic and lifestyle factors and dietary quality among adolescents. Subjects were 445 adolescents (171 boys, 274 girls; 14 to 18 y old) selected from the Palma de Mallorca (Balearic Islands, Spain) school census (96% participation) using two-stage probability sampling. The study protocol included dietary intake by means of a validated semiquantitative food-frequency questionnaire; sociodemographic factors of sex, maternal level of education, parental occupational status, and maternal region of origin; physical activity; and body weight and height measurements. Body mass index was calculated and energy intake expressed as multiples of basal metabolic rate. Mean daily energy intakes were 12.9 MJ for boys and 12.0 MJ for girls. Boys showed a higher percentage of energy from carbohydrates but a lower percentage from proteins and fat than did girls (44.9 versus 41.6, 18.8 versus 19.8, and 36.3 versus 38.5, respectively). Dietary fiber intake was within the recommended levels. Mineral and vitamin intakes generally met their estimated needs, except for vitamins A and D, which covered less than two-thirds of the recommended intake. Maternal educational level was positively correlated with dietary mineral and vitamin intakes. A positive relation between physical activity and dietary intakes of carbohydrate and of mineral and vitamin was found. Maternal level of education and physical activity are associated to the quality of diet among adolescents in Palma de Mallorca.

Associations between sociodemographic and lifestyle factors and dietary quality among adolescents in Palma de Mallorca

Objective We assessed associations between sociodemographic and lifestyle factors and dietary quality among adolescents. Methods Subjects were 445 adolescents (171 boys, 274 girls; 14 to 18 y old) selected from the Palma de Mallorca (Balearic Islands, Spain) school census (96% participation) using two-stage probability sampling. The study protocol included dietary intake by means of a validated semiquantitative food-frequency questionnaire; sociodemographic factors of sex, maternal level of education, parental occupational status, and maternal region of origin; physical activity; and body weight and height measurements. Body mass index was calculated and energy intake expressed as multiples of basal metabolic rate. Results Mean daily energy intakes were 12.9 MJ for boys and 12.0 MJ for girls. Boys showed a higher percentage of energy from carbohydrates but a lower percentage from proteins and fat than did girls (44.9 versus 41.6, 18.8 versus 19.8, and 36.3 versus 38.5, respectively). Dietary fiber intake was within the recommended levels. Mineral and vitamin intakes generally met their estimated needs, except for vitamins A and D, which covered less than two-thirds of the recommended intake. Maternal educational level was positively correlated with dietary mineral and vitamin intakes. A positive relation between physical activity and dietary intakes of carbohydrate and of mineral and vitamin was found. Conclusions Maternal level of education and physical activity are associated to the quality of diet among adolescents in Palma de Mallorca.

Energy requirements of women of reproductive age

The energy requirements of women have been based on total energy expenditure (TEE) derived from the factorial approach or as multiples of basal metabolic rate (BMR). This study was designed to reevaluate the energy requirements of healthy, moderately active underweight, normal-weight, and overweight women of reproductive age. The energy requirements of 116 women [n = 13 with a low body mass index (BMI), n = 70 with a normal BMI, and n = 33 with a high BMI] were estimated from TEE measured by the doubly labeled water method. Twenty-four-hour EE and BMR were measured by room respiration calorimetry, activity EE was estimated from nonbasal EE as TEE - BMR, and physical activity level was calculated as TEE/BMR. Body composition was derived from a multicomponent model. Fitness, strength, and physical activity level were assessed, and fasting serum indexes were measured. Energy requirements differed among the low-BMI (8.9 +/- 0.9 MJ/d), normal-BMI (10.1 +/- 1.4 MJ/d), and high-BMI (11.5 +/- 1.9 MJ/d) groups (P = 0.02-0.001, all pairwise comparisons). Major predictors of BMR, 24-h EE, and TEE were weight, height, and body composition; minor predictors were fasting metabolic profile and fitness. Fat-free mass and fat mass accounted for the differences in EE seen between the BMI groups. The mean physical activity level of 1.86 suggested that the multiples of BMR used to estimate energy requirements have been underestimated. Recommended energy intakes for healthy, moderately active women of reproductive age living in industrialized societies should be revised on the basis of TEE.

High levels of habitual physical activity in west African adolescent girls and relationship to maturation, growth, and nutritional status: results from a 3-year prospective study.

This study examines energy expenditure and physical activity levels for a sample of 40 adolescent girls of the Sereer ethnic group of rural Senegal. The girls were 13.3 +/- 0.5 years at the start of the study (June 1997) and were followed annually for the next 2 years during puberty. Data collected during each round included: 1) pubertal status (as assessed by breast development and occurrence of menarche); 2) selected anthropometric dimensions (weight, stature, arm circumference, and six skinfolds); and 3) physical activity levels quantitatively assessed using CSA accelerometers. During rounds 1 and 3, activity was also qualitatively reported by direct minute-by-minute observations. A food consumption survey was performed once during the 3(rd) round, using an individual food weighing method. Girls of this sample had high levels of energy expenditure with daily physical activity levels (PALs) ranging from 1.70 to 1.85 multiples of basal metabolic rate. Energy intakes were, on average, sufficient to meet energy and protein requirements, although micronutrient deficiencies were likely to exist. Activity levels declined with age between the 1(st) and 3(rd) rounds. Stepwise regression analyses showed that stature was negatively correlated with both total daily and day-time activity, whereas the body mass index was positively associated with this measure. Pubertal status and subcutaneous fatness were not significant predictors of activity levels. The contribution of these adolescent girls to the everyday tasks of the household was considerable. They spent more than 3 hours 30 minutes per day in domestic duties.

Assessment of physical activity among rural Senegalese adolescent girls: influence of age, sexual maturation, and body composition.

To analyze the level of habitual physical activity and its relationship with age, maturational stage, and growth status in a group of adolescent Senegalese girls. Physical activity was assessed for 3 consecutive years in a sample of 40 girls of rural origin. They were 13.3 +/- 0.5 years old at the beginning of the study and belonged to a Sereer community located in the center of Senegal. Minute-by-minute movement counts using accelerometers enabled quantification of levels of physical activity. The assessment was performed during a 4-day period in the first round (1997) and during a 3-day period in 1998 and 1999. Half of the girls were not yet pubescent during the first round, and the whole sample displayed growth retardation in weight and stature, compared with the World Health Organization/National Center for Health Statistics reference. Estimated levels of activity were high, ranging from 1.80 to 1.85 multiples of basal metabolic rate. There was a clear decline in the activity level during the course of study. Schoolgirls were less active than the others. Mature adolescents showed more activity during the night. A weak, but significant and positive correlation existed between body mass index and activity during the day; during the night, there was a positive correlation with fat and lean body mass. Factors determining the activity level were intricate but greater maturity and better nutritional status appeared to be positively related to the activity level.

Energy expenditure, physical exertion and time allocation among Hulispeaking people in the Papua New Guinea Highlands

Objectives: The study aimed to (1) elucidate the energetic adaptations of Huli people by comparing the three sub-populations in relation to their diversified natural and socioeconomic environment, based on energy expenditure and time allocation data; and (2) assess the applicability of a new index of physical exertion levels of activities (physical exertion index: PEI). Research design and methods: Married males and females (n = 43) were selected, including 14 from a hilly village, 13 from a flat swampy village and 16 migrants to a town. Continuous heart rate (HR) monitoring, in conjunction with minute-by-minute observation of activities, was undertaken. Total energy expenditure was assessed by flex-HR method and physical activity level (PAL) was calculated as multiples of basal metabolic rate. Observed activities were divided into 15 categories and the PEI was calculated for each: PEI= (mean HR of a categorized activity)/(flex HR) x 100. Results : No significant difference was found in PAL among the three sub-populations: 1.77, 1.92 and 1.81 for men and 1.78, 1.98 and 1.66 for women in hilly and flat villages, and a town, respectively. The comparison of the two village groups revealed that hilly terrain did not affect substantially the physical intensity of agricultural activities. On the other hand, the town migrants were engaged in sedentary paid jobs and these were less energy consuming than agricultural work. However, the different energy costs between paid jobs and agricultural work were offset by longer work time in the town group than in the two village groups (251 vs 50 or 70 min in males; 258 vs 152 or 138 min in females), resulting in similar PAL in the three groups. Conclusions: Despite contrasting natural and social environments, no significant difference was found in daily physical activity level among the three sub-populations (two villages and a town) of Huli-speaking people in Papua New Guinea Highlands.

Optimal Foraging and Beyond: How Starlings Cope with Changes in Food Availability

Foraging adaptations include behavioral and physiological responses, but most optimal foraging models deal exclusively with behavioral decision variables, taking other dimensions as constraints. To overcome this limitation, we measured behavioral and physiological responses of European starlings Sturnus vulgaris to changes in food availability in a laboratory environment. The birds lived in a closed economy with a choice of two foraging modes (flying and walking) and were observed under two treatments (hard and easy) that differed in the work required to obtain food. Comparing the hard with the easy treatment, we found the following differences. In the hard treatment, daily amount of work was higher, but daily intake was lower. Even though work was greater, total daily expenditure was smaller, partly because overnight metabolism was lower. Body mass was lower, but daily oscillation in body mass did not differ. Feces' caloric density was lower, indicating greater food utilization. Energy expenditure rate expressed as multiples of basal metabolic rate (BMR) increased during the working period from 3.5 x BMR (easy) to 5.2 x BMR (hard), but over the 24-h period, it was close to 2.4 x BMR in both treatments. We also found that rate of expenditure during flight was very high in both treatments (52.3 W in easy and 45.5 W in hard), as expected for short (as opposed to cruising) flights. The relative preferences between walking and flying were incompatible with maximizing the ratio of energy gains per unit of expenditure (efficiency) but compatible with maximizing net gain per unit of time during the foraging cycle (net rate). Neither currency explained the results when nonforaging time was included. Time was not a direct constraint: the birds rested more than 90% of the time in both treatments. Understanding this complex picture requires reasoning with ecological, physiological, and cognitive arguments. We defend the role of optimality as an appropriate tool to guide this integrative perspective.

Optimal Foraging and Beyond: How Starlings Cope with Changes in Food Availability

Foraging adaptations include behavioral and physiological responses, but most optimal foraging models deal exclusively with behavioral decision variables, taking other dimensions as constraints. To overcome this limitation, we measured behavioral and physiological responses of European starlings Sturnus vulgaris to changes in food availability in a laboratory environment. The birds lived in a closed economy with a choice of two foraging modes (flying and walking) and were observed under two treatments (hard and easy) that differed in the work required to obtain food. Comparing the hard with the easy treatment, we found the following differences. In the hard treatment, daily amount of work was higher, but daily intake was lower. Even though work was greater, total daily expenditure was smaller, partly because overnight metabolism was lower. Body mass was lower, but daily oscillation in body mass did not differ. Feces' caloric density was lower, indicating greater food utilization. Energy expenditure rate expressed as multiples of basal metabolic rate (BMR) increased during the working period from 3.5 x BMR (easy) to 5.2 x BMR (hard), but over the 24‐h period, it was close to 2.4 x BMR in both treatments. We also found that rate of expenditure during flight was very high in both treatments (52.3 W in easy and 45.5 W in hard), as expected for short (as opposed to cruising) flights. The relative preferences between walking and flying were incompatible with maximizing the ratio of energy gains per unit of expenditure (efficiency) but compatible with maximizing net gain per unit of time during the foraging cycle (net rate). Neither currency explained the results when nonforaging time was included. Time was not a direct constraint: the birds rested more than 90% of the time in both treatments. Understanding this complex picture requires reasoning with ecological, physiological, and cognitive arguments. We defend the role of optimality as an appropriate tool to guide this integrative perspective.

Physical activity, cardiorespiratory fitness, motor performance, and growth of senegalese pre-adolescents.

Profiles of usual physical activity, cardiorespiratory fitness, motor performance, and growth were measured regularly for 2 years in 40 rural Senegalese (Wolof) children-20 boys and 20 girls-who were 10 or 11 years of age and clinically healthy at the beginning of the study. Compared to National Center for Health Statistics (NCHS) reference data, the children showed lower weight-for-age and height-for-age throughout the period of observation; the increments of height from year to year were not remarkable and growth spurts were not observed during the study period. The motor performance (running, jumping, throwing) and spirometer test results were inferior to age-matched American children. When adjusted for actual weight and height, jumping and throwing results were similar to those of American children, but running results remained inferior. Cardiorespiratory function appeared inferior to American children of the same age, although speed of recovery after exertion demonstrated good cardiorespiratory efficiency. Physical activity, directly observed over 2-day periods on 4 occasions, corresponded to an average energy expenditure of 1.66 Mets (multiples of basal metabolic rate) (boys) and 1.76 Mets (girls), which are close to the FAO/WHO/UNU values for age. The higher energy expenditure of girls could be explained by their participation in domestic tasks. Both boys and girls spent an average of 42 minutes/day on activities equivalent to energy consumption rates equal or greater than 4.8 Mets. Significant correlations existed between the activity index and cardiorespiratory fitness in boys, and between the activity index and motor performances in girls. Physical aptitudes of sampled children appear compatible with the demands of their social and agricultural tasks. However, it appears that persistent malnutrition may have stunted their growth and motor performances. © 1993 Wiley-Liss, Inc.

Aerobic capacity of forestry workers and physical demands of forestry operations.

The present study aimed at evaluating the aerobic capacities of forestry workers and the physical demands of their occupation. A submaximal cycle ergometer test was conducted on 22 male forestry workers and 15 male sedentary office workers aged 40-59 years. The slope of the regression line of heart rates on given exercise intensities was significantly smaller in the forestry workers than in the office workers. The mean heart rate of the forestry workers was 9 beats.min-1 less than that of the office workers at the initial exercise intensity of 50 W. This difference increased to 25 beats.min-1 at 175 W. For 6 of the 22 forestry workers, heart rates were recorded continuously during a usual workday. The metabolic rates, as multiples of basal metabolic rate (in met) of various forestry activities were estimated from the average heart rate during the activity of interest and a predicted maximal oxygen consumption of the subject obtained from a submaximal cycle ergometer test. The mean energy expenditure was 4.5 met with a range of 3.3-6.3 met for an average of 509 min at a worksite. These results indicated that the forestry workers had high aerobic capacities and this was ascribed to the high physical demands of their occupation.

Energetic cost of standard activities in Gurkha and British soldiers

Measurements of basal metabolic rate and energy expenditure at lying, sitting, standing, and performing a step test at four levels of exercise, were made on Gurkha soldiers stationed in Britain and on British controls matched by body weight and occupational background. There was no significant difference in basal metabolic rate (BMR), nor in the energy cost of lying, sitting and standing between the two groups. Gurhas showed significantly lower gross and net energy expenditure, and so significantly greater net mechanical efficiency, at the lower levels of step exercise. The ratio of gross energy expenditure to BMR was lower in Gurkhas at the lowest rates of stepping compared with the British controls. These results suggest that the energy cost of some physical activities expressed as multiples of BMR may not be constant across populations.

Proper Expression of Metabolizable Energy in Avian Energetics

-We review metabolizable energy (ME) concepts and present evidence suggesting that the form of ME used for analyses of avian energetics can affect interpretation of results. Apparent ME (AME) is the most widely used measure of food energy available to birds. True ME (TME) differs from AME in recognizing fecal and urinary energy of nonfood origin as metabolized energy. Only AME values obtained from test birds fed at maintenance levels should be used for energy analyses. A practical assay for TME has shown that TME estimates are less sensitive than AME to variation in food intake. The TME assay may be particularly useful in studies of natural foods that are difficult to obtain in quantities large enough to supply test birds with maintenance requirements. Energy budgets calculated from should be expressed as kJ of AME and converted to food requirements with estimates of metabolizability given in kJ AME/g. Energy budgets calculated from multiples of basal metabolic rate (a component of maintenance energy), however, should be expressed as kJ of either TME or net energy depending on ambient temperature. Energy units should be stated explicitly to improve comparability and in some cases accuracy of energy analyses. Metabolizable energy (ME; see Appendix for explanation of this and other abbreviations) is a measure of the energy available to birds from their diet (Vohra 1966). In avian energetics, ME is used to convert daily energy budgets (DEB; see, e.g., King 1974, Kendeigh et al. 1977) to weight of food required to supply energy needed by individuals or populations (Kendeigh et al. 1977, Wiens and Dyer 1977). ME has been used in this way for DEBs based on existence metabolism (EM; Kendeigh et al. 1977) and multiples of basal metabolic rate (BMR; King 1973, 1974, Ricklefs 1974, Prince 1979). ME can be expressed as either apparent (AME) or true (TME) metabolizable energy (Harris 1966). The form of ME used in modeling calculations has almost always been AME, although not often specified as such (Ricklefs 1974, Wiens and Dyer 1975, 1977, Craig et al. 1979, Prince 1979, Raveling 1979, Ashkenazie and Safriel 1979, Sugden et al. 1981). AME has been the traditional measure of ME in studies of birds because, until recently, standard feeding trials did not separate total excretory energy into independent estimates of fecal plus urinary energy (FE + UE) and of metabolic fecal plus endogenous urinary energy (fecal and urinary energy of nonfood origin; FErn + UE,; Sibbald 1976). However, TME correctly recognizes FErn and UE, as metabolized energy (Harris 1966, Owen and Reinecke 1979) and is, therefore, a more direct measure of energy availability. Our purposes here are to provide a brief review of ME concepts and to show that the form of ME used for energetics analyses can affect interpretation of results. AME is usually estimated with data obtained from test birds confined in cages. The birds are fed experimental diets over a number of days during which total food ingested and excreta voided are measured. This is the total collection method (Vohra 1972). Bomb calorimetry is used to determine the energy content of food and excreta, and AME (in kJ/g) is calculated from the equation: AME = [(GE,)(Qi) (GEe)(Qe)]/Qi (1) where GE, and GE, = the gross energy density of food that is eaten (intake) and excreta (in kJ/g), and Qj and Q, = the quantity of food eaten and excreta produced (in g). Alternatively, a nondigestible chemical (Vohra 1972) or crude fiber (Almquist and Halloran 1971) can be used as a tracer to relate excreta production to food intake: AME = GE, (% T,/% Te)GE (2) where % T, and % T, = percent tracer in the food and excreta. Expressions of energy availability that use digestive efficiency (Ashkenazie and Safriel 1979, Raveling 1979), assimilation eff ciency (Ricklefs 1974), or metabolizable en-