Energy metabolism in relation to body composition and gender in adolescents

Effects of obesity on the oxygen cost of breathing in children

The objective of this study was to examine the effects of obesity on the oxygen (O₂) cost of breathing using the eucapnic voluntary hyperpnea (EVH) technique in 10- and 11-year-old children. Seventeen children (8 without and 9 with obesity) underwent EVH trials at two levels of ventilation for assessing the O₂ cost of breathing (slope of oxygen uptake, V˙O₂ vs. minute ventilation) and a dual energy x-ray absorptiometry scan. Resting and EVH V˙O₂ was higher in children with obesity when compared with children without obesity (P = 0.0096). The O₂ cost of breathing did not statistically differ between children without (2.09 ± 0.46 mL/L) and with obesity (2.08 ± 0.64 mL/L, P = 0.99), but the intercept was significantly greater in children with obesity. Chest mass explained 85 % of the variance in resting V˙O₂ in children with obesity. Higher resting energy requirements, attributable to increased chest mass, can increase the absolute metabolic costs of exercise and hyperpnea in children with obesity.

Double burden of malnutrition among adolescents in rural West Bengal, India

OBJECTIVES

The aims of this study were to investigate the prevalence of underweight, stunting, and overweight among adolescents in rural West Bengal, India, and identify factors contributing to these forms of malnutrition.

METHODS

This was a cross-sectional study conducted within the Birbhum Health and Demographic Surveillance System in West Bengal, India. Participants were male and female adolescents 10 to 19 y of age (N = 5521). Body mass index (BMI) was calculated using measured heights and weights and z-scores based on the 2007 World Health Organization growth standards. Information on demographic characteristics, diet, and health behaviors was collected through face-to-face interviews using a standardized questionnaire. Modified Poisson regression was used to estimate prevalence ratios (PRs) and 95% confidence intervals (CIs) for the association between each risk factor and outcome.

RESULTS

The proportion of underweight was 26.6% overall: 31.1% among boys, and 21.1% among girls. The proportion of stunting was 25% overall: 23.3% among boys and 26.9% among girls. Of the participants, 4.6% were overweight or obese: 4.1% boys and 5.2% girls. Compared with boys, girls had a reduced likelihood of being underweight (adjusted PR, 0.67; 95% CI, 0.59-0.75). Multivariate models also showed that socioeconomic status was strongly associated with all nutritional outcomes. Not having a toilet facility in one's household and poor hand hygiene were also associated with a greater likelihood of stunting.

CONCLUSION

The present results suggested that adolescents in Birbhum, India are substantially affected by the double burden of malnutrition. Nutritional interventions should incorporate efforts to reduce socioeconomic inequality.

Metabolic Equivalent in Adolescents, Active Adults and Pregnant Women

“Metabolic Equivalent” (MET) represents a standard amount of oxygen consumed by the body under resting conditions, and is defined as 3.5 mL O₂/kg × min or ~1 kcal/kg × h. It is used to express the energy cost of physical activity in multiples of MET. However, universal application of the 1-MET standard was questioned in previous studies, because it does not apply well to all individuals. Height, weight and resting metabolic rate (RMR, measured by indirect calorimetry) were measured in adolescent males (n = 50) and females (n = 50), women during pregnancy (gestation week 35–41, n = 46), women 24–53 weeks postpartum (n = 27), and active men (n = 30), and were compared to values predicted by the 1-MET standard. The RMR of adolescent males (1.28 kcal/kg × h) was significantly higher than that of adolescent females (1.11 kcal/kg × h), with or without the effects of puberty stage and physical activity levels. The RMR of the pregnant and post-pregnant subjects were not significantly different. The RMR of the active normal weight (0.92 kcal/kg × h) and overweight (0.89 kcal/kg × h) adult males were significantly lower than the 1-MET value. It follows that the 1-MET standard is inadequate for use not only in adult men and women, but also in adolescents and physically active men. It is therefore recommended that practitioners estimate RMR with equations taking into account individual characteristics, such as sex, age and Body Mass Index, and not rely on the 1-MET standard.

A comparison of work-related physical activity levels between inpatient and outpatient physical therapists: an observational cohort trial

Background

Physical therapists (PTs) work in a variety of healthcare settings with varied levels of physical activity demands placed on them. The purpose of this study is to compare the physical activity (PA) levels between PTs in inpatient versus outpatient environments for one work week using a cross-sectional design.

Methods

Sixty-one PTs (30 inpatient, 31 outpatient) wore a tri-axial accelerometer and inclinometer for one work-week. The number steps-per-day, PA intensities, energy expenditures and postural positions adopted during the work day were recorded.

Result

Significantly longer amounts of time spent sitting was found for inpatient PTs regardless of the significantly higher number of steps-per-day. Outpatient PTs had a higher number of breaks from sedentary activity with those breaks being longer than the inpatient PTs. The percentage of time spent performing moderate-vigorous PA approached significance implying more time was spent performing these types of activities for outpatient PTs. The energy expenditures between the two groups of PTs were not different.

Conclusion

This study compared the differences in physical activity levels between physical therapists who worked at inpatient versus outpatient environment as little is known about their activity levels. Inpatient physical therapists took more steps per day than outpatient physical therapists but the outpatient physical therapists were less sedentary and took more frequent and longer breaks from sedentary activities. The energy expenditures were similar between both types of therapists and this may be reflective of the gender and bodyweight differences between the groups that equalizes the energy expenditures. The findings of this study suggests that there are differences in the physical activity demands between inpatient and outpatient physical therapists. The results of this study may serve dual purposes: (1) employers may be able to more accurately describe the expected physical activity demands to future employees; (2) individuals tasked with preparing PTs to physically manage their work environment can outline training programs that are diverse based on the specific work environment of PTs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-016-2119-y) contains supplementary material, which is available to authorized users.

Mechanical efficiency during a cycling test is not lower in children with excess body weight and low aerobic fitness

OBJECTIVE

The aims of this study were to assess the association between (i) body weight status and mechanical efficiency (ME); and (ii) ME and aerobic fitness in children aged 8-10 years.

DESIGN AND METHODS

The sample included 464 prepubertal children (258 boys). A total of 288 were normal-weight (NW); 84 overweight (OW); and 92 obese (OB). Subjects performed an incremental maximal cycling test with indirect calorimetry. MEcrude (%) was calculated for the first five stages of the protocol (25, 50, 75, 100, and 125 W) as follows: work produced, in watts total energy consumption, in watts(-1) · 100(-1). For MEnet, resting energy consumption was subtracted from total energy consumption. Energy consumption was calculated as follows: (4.94 · respiratory exchange ratio + 16.04) · VO2, in ml · min(-1) · 60(-1).

RESULTS

MEcrude was significantly higher in NW compared to OW and OB children and in OW compared to OB children at 25, 50, 75, 100, and 125 W. In contrast, MEnet did not differ significantly among NW, OW, and OB children. No statistically significant association was found between crude or net ME and peak oxygen consumption (VO2 peak; in ml · kg(-1) · min(-1)); therefore, the ability to transfer chemical energy to mechanical work is maintained in children aged 8-10 years old regardless of body weight status and aerobic fitness. Moreover, higher values of MEcrude during exercise are explained by elevated oxygen consumption at rest and not by energy consumed during physical activity.

CONCLUSIONS

These results highlight that prepubertal children are equally efficient since they are able to perform a physical task such as cycling using the same proportion of energy regardless of their body weight status.

Balanço energético em crianças e adolescentes com bronquiolite obliterante pós-infecciosa

OBJETIVOS: Quantificar o gasto e estimar a ingestão energética de crianças e adolescentes com bronquiolite obliterante pós-infecciosa e comparar com crianças e adolescentes hígidos. MÉTODOS: Estudo transversal com 72 crianças e adolescentes de 8 a 18 anos. Compararam-se dois grupos de 36 indivíduos - um com diagnóstico de bronquiolite obliterante e outro hígido -, os quais foram pareados pelo sexo, idade e classificação do índice de massa corporal. Para avaliação nutricional, utilizaram-se a antropometria e a composição corporal. O gasto energético foi medido pela calorimetria indireta; o fator atividade, pelo recordatório 24h de atividades físicas, e a ingestão energética, pelos inquéritos alimentares. RESULTADOS: O grupo com bronquiolite obliterante e o grupo-controle apresentaram respectivamente: índice de massa corporal de M=18,9, DP=4,0kg/m² e M=18,8, DP=3,4kg/m²; gasto energético de repouso de M=1717,6, DP=781,5 e M=2019,9, DP=819; gasto energético total de M=2677,5, DP=1514,0kcal/dia e M=3396,1, DP=1557,9kcal/dia; estimativa da ingestão energética de M=2294,1, DP=746,7kcal/dia e M=2116,5, DP=612,1kcal/dia. O gasto energético de repouso (p=0,102) e o gasto energético total (p=0,051) não foram diferentes entre os grupos, mesmo quando ajustados pela massa magra. Não houve diferenças estatisticamente significativas entre o o gasto energético total e o consumo energético no grupo com bronquiolite obliterante (p=0,202). O grupo-controle consumiu menos calorias do que o previsto pelo gasto energético total (p<0,001). CONCLUSÃO: O gasto energético de repouso e o gasto energético total foram semelhantes entre os grupos. A estimativa da ingestão energética dos hígidos foi menor que o gasto energético total. O grupo com bronquiolite obliterante apresentava um balanço energético adequado.

Energy prediction equations are inadequate for obese Hispanic youth

Assessing energy requirements is a fundamental activity in clinical dietetics practice. A study was designed to determine whether published linear regression equations were accurate for predicting resting energy expenditure (REE) in fasted Hispanic children with obesity (aged 7 to 15 years). REE was measured using indirect calorimetry; body composition was estimated with whole-body air displacement plethysmography. REE was predicted using four equations: Institute of Medicine for healthy-weight children (IOM-HW), IOM for overweight and obese children (IOM-OS), Harris-Benedict, and Schofield. Accuracy of the prediction was calculated as the absolute value of the difference between the measured and predicted REE divided by the measured REE, expressed as a percentage. Predicted values within 85% to 115% of measured were defined as accurate. Participants (n=58; 53% boys) were mean age 11.8±2.1 years, had 43.5%±5.1% body fat, and had a body mass index of 31.5±5.8 (98.6±1.1 body mass index percentile). Measured REE was 2,339±680 kcal/day; predicted REE was 1,815±401 kcal/day (IOM-HW), 1,794±311 kcal/day (IOM-OS), 1,151±300 kcal/day (Harris-Benedict), and, 1,771±316 kcal/day (Schofield). Measured REE adjusted for body weight averaged 32.0±8.4 kcal/kg/day (95% confidence interval 29.8 to 34.2). Published equations predicted REE within 15% accuracy for only 36% to 40% of 58 participants, except for Harris-Benedict, which did not achieve accuracy for any participant. The most frequently accurate values were obtained using IOM-HW, which predicted REE within 15% accuracy for 55% (17/31) of boys. Published equations did not accurately predict REE for youth in the study sample. Further studies are warranted to formulate accurate energy prediction equations for this population.

Gasto energético em adolescentes asmáticos com excesso de peso: calorimetria indireta e equações de predição

OBJETIVO: Comparar o gasto energético medido por calorimetria indireta com o estimado por equações de predição entre adolescentes asmáticos e não asmáticos. MÉTODOS: Trata-se de estudo transversal com 69 adolescentes de 10 a 18 anos. Foram comparados três grupos pareados (asmáticos com excesso de peso, asmáticos eutróficos e não asmáticos com excesso de peso). Para avaliação nutricional utilizaram-se medidas antropométricas e de composição corporal. O gasto energético foi medido por calorimetria indireta e estimado por fórmulas de predição. RESULTADOS: Cada grupo foi composto por 23 adolescentes, dos quais 10 do sexo feminino, com média de idade de M=12,4, DP=2,4 anos. O gasto energético de repouso, pela calorimetria indireta nos asmáticos com excesso de peso, foi de M=1550,2, DP=547,2kcal/dia; nos asmáticos eutróficos, M=1540,8, DP=544,2kcal/dia; e nos não asmáticos com excesso de peso, M=1697,2, DP=379,8kcal/dia, com resultado semelhante entre os grupos, mesmo quando ajustado pela massa magra e massa gorda (f=0,186; p=0,831). Obtiveram-se achados semelhantes entre o gasto energético medido pela calorimetria indireta e o estimado pelas fórmulas de predição, com exceção da fórmula de Harris-Benedict, que subestimou o gasto energético nos asmáticos eutróficos e nos não asmáticos com excesso de peso. CONCLUSÃO: O gasto energético de repouso não foi estatisticamente diferente entre os grupos asmáticos e não asmáticos, mesmo quando ajustado pela massa magra e massa gorda. Para os três grupos, as equações de predição são úteis para estimar o gasto energético de repouso e o gasto energético total.

Validation of predictive equations for resting energy expenditure in obese adolescents

BACKGROUND

When the resting energy expenditure (REE) of overweight and obese adolescents cannot be measured by indirect calorimetry, it has to be predicted with an equation.

OBJECTIVE

The aim of this study was to examine the validity of published equations for REE compared with indirect calorimetry in overweight and obese adolescents.

DESIGN

Predictive equations based on weight, height, sex, age, fat-free mass (FFM), and fat mass were compared with measured REE. REE was measured by indirect calorimetry, and body composition was measured by dual-energy X-ray absorptiometry. The accuracy of the REE equations was evaluated on the basis of the percentage of adolescents predicted within 10% of REE measured, the mean percentage difference between predicted and measured values (bias), and the root mean squared prediction error (RMSE).

RESULTS

Forty-three predictive equations (of which 12 were based on FFM) were included. Validation was based on 70 girls and 51 boys with a mean age of 14.5 y and a mean (+/-SD) body mass index SD score of 2.93 +/- 0.45. The percentage of adolescents with accurate predictions ranged from 74% to 12% depending on the equation used. The most accurate and precise equation for these adolescents was the Molnar equation (accurate predictions: 74%; bias: -1.2%; RMSE: 174 kcal/d). The often-used Schofield-weight equation for age 10-18 y was not accurate (accurate predictions: 50%; bias: +10.7%; RMSE: 276 kcal/d).

CONCLUSIONS

Indirect calorimetry remains the method of choice for REE in overweight and obese adolescents. However, the sex-specific Molnar REE prediction equation appears to be the most accurate for overweight and obese adolescents aged 12-18 y. This trial was registered at www.trialregister.nl with the Netherlands Trial Register as ISRCTN27626398.

Energy expenditure and estimated caloric intake in asthmatic adolescents with excess body weight

OBJECTIVE

To measure resting energy expenditure (REE) and to estimate caloric intake of asthmatic adolescents with excess body weight and compare results with those groups of eutrophic asthmatic adolescents and non-asthmatic adolescents with excess body weight.

METHODS

This cross-sectional study categorized 69 adolescents aged 10 to 18 y into three matched groups. Nutritional status was assessed using anthropometric and body composition measurements. Indirect calorimetry was used to measure energy expenditure, and caloric intake was estimated from dietary recalls.

RESULTS

In each group, there were 23 adolescents (10 girls) aged 12.39 ± 2.40 y. Results for each group were as follows. For asthmatic adolescents with excess body weight, body mass index (BMI) was 24.83 ± 2.73 kg/m(2), REEs were 1550.24 ± 547.23 kcal/d and 27.69 ± 11.33 kcal · kg(-1) · d(-1), and estimated caloric intake was 2068.75 ± 516.66 kcal/d; for eutrophic asthmatic adolescents, BMI was 19.01 ± 2.10 kg/m(2), REEs were 1540.82 ± 544.22 kcal/d and 36.65 ± 15.04 kcal · kg(-1) · d(-1), and estimated caloric intake was 2174.05 ± 500.55 kcal/d; and for non-asthmatic adolescents with excess body weight, BMI was 25.35 ± 3.66 kg/m(2), REEs were 1697.24 ± 379.84 kcal/d and 28.18 ± 6.70 kcal · kg(-1) · d(-1), and estimated caloric intake was 1673.17 ± 530.68 kcal/d. Absolute REE values between groups were not statistically different, even after correction for lean mass and fat mass (F = 0.186, P = 0.831). REE (kilocalories per kilogram per day) was significantly higher in the group of eutrophic asthmatic adolescents (P = 0.016). Estimated caloric intake was greater than REE only in the group of adolescents with asthma.

CONCLUSION

The REE was not significantly different among groups, and REE (kilocalories per kilogram per day) was higher in the group of eutrophic asthmatic adolescents. Estimated caloric intake was greater than REE in the group of adolescents with asthma.

Energy recommendations for normal weight, overweight and obese children and adolescents: are different equations necessary?

In 2002/2005, separate energy requirement equations were generated by the Institute of Medicine's (IOM) Dietary Reference Intake process for normal weight and overweight/obese children and adolescents. The current paper questions the theoretical rationale of having two sets of equations (based solely on body-weight classification): when body weight is considered, overweight and obese children and adolescents do not seem to differ from their normal weight counterparts in energy expended for basal metabolism or physical activity tasks. However, energy needs for weight maintenance among overweight/obese girls were consistently higher when predicted using the equations for overweight/obese individuals compared with those developed for normal weight individuals. In contrast, among overweight/obese boys, they were consistently lower. Although the differences are within the variability of the estimates, even theoretical support for a higher energy intake (as occurs in girls) seems unwise because of the potential contribution to a higher body mass in children who are already at risk. It is the opinion of the authors that the IOM revisit the use of two separate equations and generate one set that is appropriate for all children and adolescents.

The effect of sibutramine on energy expenditure and body composition in obese adolescents

CONTEXT

Childhood obesity is now considered to be an epidemic. Drug therapy in this age group remains a topic of research.

OBJECTIVE

The objective of this study was to examine the effect of treatment with sibutramine (10 mg) on body composition and energy expenditure in obese adolescents.

DESIGN

The study was conducted as a randomized, double-blind, placebo-controlled trial.

SETTING

The study was set in an obesity research center.

PATIENTS

The patients were 24 obese adolescents (age 12-17 yr, 11 boys); four patients withdrew.

INTERVENTION

Intervention was sibutramine (Meridia) or placebo in combination with an energy-restricted diet and exercise plan for 12 wk, followed by an identical, but medication-free, treatment period (follow-up).

MAIN OUTCOME MEASURE

Change in body mass index (BMI) sd score (BMI-SDS) was the principal measure of efficacy. Body composition and total energy expenditure were measured by stable isotopes and further calculated according to the four-component model, using underwater weighing and dual x-ray absorptiometry. Basal metabolic rate (BMR) was measured by ventilated hood and adjusted for sex and body composition (BMRadj).

RESULTS

After intervention, the decrease in BMI-SDS was comparable in both groups. During follow-up, BMI further decreased in the placebo group but stabilized in the sibutramine group. Changes in the percentage of fat mass were not different between both groups. BMRadj decreased in the placebo group and remained constant in the sibutramine group. During follow-up, BMRadj decreased in the sibutramine group and increased in the placebo group. Changes in total energy expenditure were not significantly different.

CONCLUSION

The effect of sibutramine on BMI-SDS was not significant. Sibutramine may diminish the decrease in BMRadj associated with energy restriction in obese adolescents.

Cardiopulmonary exercise capacity, muscle strength, and physical activity in children and adolescents with achondroplasia

OBJECTIVE

To study in children with achondroplasia the response to exercise and muscle strength compared with healthy peers and to describe the relation between exercise capacity, anthropometric factors, and physical activity.

STUDY DESIGN

Patients (7 boys and 10 girls; mean age, 11.8 +/- 3.3 years) with achondroplasia performed a maximal treadmill exercise test. Anthropometric variables and muscle strength were measured and compared with the general population. The level of everyday physical activity was measured by using a diary. Functional ability was measured by using the Activity Scale for Kids.

RESULTS

The exercise capacity of the children with achondroplasia was significantly reduced compared with reference values. All anthropometrical measurements differed significantly from reference values. There was a decrease in muscle strength in almost all muscle groups. We found a reduced physical activity level and impairments in functional ability.

CONCLUSIONS

Cardiopulmonary exercise capacity and muscle strength in children with achondroplasia was reduced compared with reference values. Children with achondroplasia have a unique response to exercise. Clinicians should take these characteristic differences into account when the exercise capacity of subjects with achondroplasia is being tested.

Excess male chronic energy deficiency among adolescents: a cross-sectional study in the context of patrilineal and matrilineal societies in Northeast India

OBJECTIVE

To determine the sex differences in chronic energy deficiency (CED) among adolescents in the context of patrilineal and matrilineal societies in Northeast India.

DESIGN

Cross-sectional, community-based study of the Hmar patrilineal society and the Khasi (War and Khynriam) matrilineal society.

SETTING

Mizoram and Meghalaya in Northeast India.

SUBJECTS

In total, 1733 adolescent boys and girls aged 9-16 y: Khynriam Khasis (n = 1005), War Khasis (n = 305) and Hmars (n = 423).

MEASUREMENTS

Weight, height, and socio-economic characteristics. Body mass index (weight in kg/height in m2) was used for assessing CED relative to the international reference values.

RESULTS

The overall prevalence of CED was significantly greater in boys than in girls. The sex differences in the prevalence of CED were 5, 10 and 6% points in the Khynriam Khasis, War Khasis and Hmars, respectively. Allowing for age and socio-economic variables, the risks of CED were about 1.82 (95% CI 1.14-2.90), 1.83 (95% CI 1.19-3.33) and 1.78 (95% CI 1.10-3.25) times greater in boys than in girls among the Khynriam Khasis, War Khasis and Hmars, respectively. Using logistic regression analysis, the prevalence of CED was negatively associated with family income across study populations. No significant association was found between CED and religion.

CONCLUSION

Patrilineal and matrilineal forms of society were not reflected in the prevalence of CED among adolescents. Subject to further studies of the research problems concerning the nutritional status of adolescents, girls fare better than boys with respect to the prevalence of CED.

As equações de predição da taxa metabólica basal são apropriadas para adolescentes com sobrepeso e obesidade?

As equações de predição conhecidas podem apresentar valores de taxa metabólica basal (TMB) diferentes daqueles medidos por calorimetria indireta. Os objetivos deste estudo foram descrever a TMB, por meio de calorimetria indireta, em meninos com sobrepeso e obesidade, de 12 a 17 anos de idade, residentes em Porto Alegre, Brasil, e comparar o valor medido com os valores de TMB estimados por equações de predição. A TMB foi medida por calorimetria indireta, pela manhã, em 35 voluntários, sob condições padronizadas de jejum, repouso e ambiente. A média (± desvio-padrão) da TMB medida foi de 1.900,5 ± 248,8kcal em 24 horas. A estimativa da TMB por equações foi significativamente maior, em três das quatro equações (6,5 a 9,5%), do que a TMB medida (p < 0,05). Os dados evidenciaram que as equações de predição não são adequadas para estimar a TMB nos meninos com sobrepeso e obesidade avaliados. O emprego dessas equações, na maioria dos casos, pode superestimar os requerimentos energéticos para meninos com características semelhantes.

Prediction of resting energy expenditure in a large population of obese children

BACKGROUND

Recommendations for energy intake in obese children rely on accurate methods for measuring energy expenditure that cannot be assessed systematically.

OBJECTIVE

The aim was to establish and validate new equations for predicting resting energy expenditure (REE), specifically in obese children.

DESIGN

REE (indirect calorimetry) and body composition (bioelectrical impedance analysis) were measured in 752 obese subjects aged 3-18 y. The first cohort (n=471) was used to establish predictive equations, the second (and independent) cohort (n=211) was used to validate these equations, and the third cohort, a follow-up group of children who lost weight (n=70), was used to examine predictive REE in the postobese period. REE values predicted with the use of various published equations and the new established equation were compared with measured REE by using the Bland-Altman method and Student's t tests.

RESULTS

In cohort 1, significant determinants of the new prediction equations were fat-free mass in boys (model R2=0.79) and age and fat-free mass in girls (model R2=0.76). External validation conducted by using the Bland-Altman method and Student's t tests, in cohort 2, showed no significant difference between measured REE and predicted REE with the new equation. When already published equations were applied, systematical bias appeared with all published equations except for that of the World Health Organization. In cohort 3, the children who lost weight, almost all equations significantly underestimated REE.

CONCLUSIONS

These new predictive equations allow clinicians to estimate REE in an obese pediatric population with sufficient and acceptable accuracy. This estimation may be a strong basis for energy recommendations in childhood obesity.

Oxygen uptakes adjusted for body composition in normal-weight and obese adolescents

OBJECTIVE

To test whether resting oxygen uptake (VO(2)), submaximal VO(2), and maximal VO(2) (VO(2max)) differs between obese adolescents (n = 18; BMI > 30) and a matched normal-weight control group after adjustment for differences in fat-free mass (FFM) and fat mass (FM).

RESEARCH METHODS AND PROCEDURES

FFM and FM were assessed by DXA. Resting VO(2), submaximal VO(2), and VO(2max) were measured by indirect calorimetry.

RESULTS

There was no difference in resting VO(2) between groups after adjusting for FFM and FM. Submaximal VO(2) did not differ between groups after adjusting for body weight. Percentage VO(2max) and NET VO(2) (VO(2max) - resting VO(2)) were significantly higher in the obese group during submaximal exercise, however not after adjusting for body weight. VO(2max) was not significantly different between groups after adjusting for FFM.

DISCUSSION

When body compositions are appropriately controlled for, resting VO(2), submaximal VO(2), and VO(2max) do not differ between obese and normal-weight adolescents. These data suggested that the higher relative VO(2) observed in obese adolescent subjects is due to their higher FM and not to an impaired VO(2max) even though they may be less physically active.