Normalization of energy expenditure data for differences in body mass or composition in children and adolescents

The most appropriate model for normalization of energy expenditure (EE) data for body mass or composition in growing children and adolescents has not been studied extensively. In this study, we investigated allometric modeling for the normalization of EE data for body mass or composition in a large cohort of children (n = 833), ages 5-19 y for a wide range of physical activities. Anthropometry was performed by standard techniques, and total body fat-free mass (FFM) and fat mass (FM) were determined by dual-energy X-ray absorptiometry (DXA). Weight status was defined as nonoverweight or overweight based on the 95th percentile for BMI. Total energy expenditure (TEE), basal energy expenditure (BEE), sleeping energy expenditure (SEE), and cycling EE were measured during 24-h room respiration calorimetry. Walking and maximal EE (MaxEE) were measured according to a treadmill protocol. Allometric or power function models were used to identify appropriate scaling parameters for EE. For BEE and lower levels of EE, weight scaled to 0.5. For cycling and treadmill walking/running, the weight exponent approached 0.7. Scaling EE for FFM resulted in exponents of 0.6 for lower rates of EE and 0.8-1.0 for higher rates of EE. Appropriate scaling of EE for body weight and composition of children and adolescents varied primarily as a function of the level of EE. In some instances, the exponents for scaling EE by body weight or composition were influenced by gender and weight status, but not by age.     

Body size, body composition, and metabolic profile explain higher energy expenditure in overweight children

Lower relative rates of energy expenditure (EE), increased energetic efficiency, and altered fuel utilization purportedly associated with obesity have not been demonstrated indisputably in overweight children. We hypothesized that differences in energy metabolism between nonoverweight and overweight children are attributable to differences in body size and composition, circulating thyroid hormones, sympathetic nervous system, and adrenomedullary activity. A total of 836 Hispanic children, 5-19 y old, participated in 24-h calorimetry, anthropometric, and dual-energy X-ray absorptiometry measurements. Biochemistries were determined by standard techniques. Absolute total EE (TEE) and its components (sleep EE, basal EE, sedentary EE, cycling EE, walking EE, activity EE, nonexercising activity thermogenesis) were higher in overweight children (P = 0.001). Net mechanical energetic efficiency of cycling was lower in overweight children (P = 0.001). Adjusting for body size and composition accounted for differences in TEE, its components, and energetic efficiency. Net carbohydrate and fat utilization did not differ between groups. TEE was independently influenced by sex, Tanner stage, fat free mass, fat mass (FM), fasting serum nonesterified fatty acids (NEFA), leptin, free thyroxine, triiodothyronine, and 24-h urinary norepinephrine and epinephrine. Fat utilization was independently associated with age2, sex, FM, fasting serum NEFA, triacylglycerol, adiponectin, leptin, total thyroxine, and free triiodothyronine. Higher EE in overweight children was largely explained by differences in body size and composition, with minor contributions of thyroid and sympathoadrenal systems. Alterations in EE, energetic efficiency, and substrate utilization were not evident in the overweight children.     

学龄儿童运动能量消耗与人体成分的关系

目的　探讨学龄期儿童运动能量消耗（AEE）与人体成分之间的关系。方法　以上海市杨浦区二联小学三、四年级62名学生为研究对象,使用代谢车测定运动能量消耗,利用生物电阻抗法测定人体成分,包括体质量、体质量指数、体脂率、脂肪含量、去脂体质量、脂肪含量指数、去脂体质量指数、肥胖度和AEE,比较超重肥胖组与非超重肥胖组儿童各指标的差异,并探讨其关系。结果　男生超重肥胖组和非超重肥胖组的运动时间［（9.70±1.91）min 比（10.00±1.97）min;t=0.336,P=0.739］、总AEE［（198.74±53.33）kJ 比 （171.54±41.75）kJ;t=-1.422,P=0.165］、AEE相对值［（0.46±0.09）kJ/(min·kg）比（0.51±0.04）kJ/(min·kg); t=2.043,P=0.051］差异均无统计学意义,超重肥胖组AEE绝对值高于非超重肥胖男生组［（20.06±3.14）kJ/min比（16.93±1.85）kJ/min;t=-2.910,P=0.007］。女生超重肥胖组与非超重肥胖组相比运动时间更短［（7.35±3.05）min 比 （9.98±1.82）min;t=2.509,P=0.027］、AEE相对值更小［（0.41±0.09）kJ/(min·kg）比 （0.51±0.07）kJ/(min·kg）;t=3.244,P=0.003］,但两组总AEE［（129.29±71.13）kJ 比 （161.50±35.38）kJ;t=1.351,P=0.203］、AEE绝对值［（16.82±3.26）kJ/min 比 （16.17±2.00）kJ/min; t=-0.676,P=0.504］差异均无统计学意义。控制年龄和性别因素后,男生AEE绝对值与体质量指数（P=0.015）、肥胖度(P=0.010)、脂肪含量(P=0.047)、去脂体质量(P=0.010）和去脂体质量指数(P=0.003)呈显著正相关,女生AEE绝对值与体成分各指标无相关性。AEE相对值与体质量指数（男：P=0.000,女：P=0.000）、肥胖度（男：P=0.002,女：P=0.000）、体脂率（男：P=0.000,女：P=0.001）、脂肪含量（男：P=0.000,女：P=0.000）、去脂体质量（男：P=0.002,女：P=0.022）和脂肪含量指数（男：P=0.000,女：P=0.000）呈显著负相关。结论　肥胖儿童AEE与体成分有关,肥胖程度越高,AEE相对值越少。儿童的体型、体成分与能量代谢存在着复杂的联系。     

Total energy expenditure, body fatness, and physical activity in children aged 6-9 y

BACKGROUND: The recent worldwide increase in the prevalence of childhood obesity may be due in part to a decrease in children's physical activity levels. OBJECTIVE: The current study of children in the years just before puberty aimed to 1) measure total energy expenditure (TEE) by use of the doubly labeled water (DLW) method, 2) determine the proportion of TEE related to physical activity, 3) investigate the relations between measures of physical activity and body fatness, and 4) investigate possible sex differences in these relations. DESIGN: The DLW technique was used to measure TEE over 10 d in 106 healthy children (52 boys) aged 7.8 +/- 0.9 y (x +/- SD). Fat-free mass, and hence fat mass, was derived from the (18)O dilution space. Resting energy expenditure (REE) was calculated with use of the Schofield equations. Physical activity level was calculated as TEE/REE. RESULTS: Mean TEE in both boys (7871 +/- 1135 kJ/d) and girls (7512 +/- 1195 kJ/d) was significantly different (P < 0.0001) from FAO/WHO/UNU recommendations (13% and 9% lower, respectively). There was no significant difference in physical activity level between boys (1.69 +/- 0.22) and girls (1.71 +/- 0.23). In boys but not girls, physical activity level was inversely correlated with BMI (r = -0.37, P < 0.01), fat mass (r = -0.46, P < 0.005), and percentage of body fat (r = -0.50, P < 0.0001). CONCLUSIONS: In boys but not girls, percentage of body fat is inversely associated with physical activity level. Physical activity is one factor contributing to body fatness in boys, but additional factors may influence the size of the fat stores in girls.     

Total energy expenditure and physical activity level in healthy young Swedish children 9 or 14 months of age

OBJECTIVES: To measure total energy expenditure (TEE) and total body water (TBW) in healthy Swedish children 9 or 14 months of age. To compare their TEE with current recommendations for energy intake. To define their body composition and relate this to energy expenditure. DESIGN:: Children were investigated at 9 or 14 months. The following variables were measured: TEE and TBW (by the doubly labelled water method), weight and length. Total body fat (TBF), sleeping metabolic rate, activity energy expenditure and physical activity level (PAL) were calculated. SUBJECTS: Thirty infants 9 months of age and 29 children 14 months of age. RESULTS:: TEE was 323+/-38, 322+/-29, 313+/-23 and 331+/-28 kJ/kg/day in 9-month-old girls, 9-month-old boys, 14-month-old girls and 14-month-old boys, respectively. At 9 months of age girls and boys contained 29.6+/-4.8 and 29.7+/-4.5% TBF, respectively. At 14 months the corresponding figures were 29.1+/-4.3 and 28.2+/-4.3%. There was a significant negative relationship between PAL and %TBF (r=-0.81, P<0.001, n=59). CONCLUSIONS: Measured TEE plus calculated energy cost of growth confirm previous estimates that the physiological energy requirements of children 9 and 14 months of age are 15-20% lower than current recommendations for energy intake. One possible interpretation of the relationship between PAL and %TBF is that children with a high TBF content are less physically active than children with less TBF. However, this relationship needs further studies.     

Resting energy expenditure, activity energy expenditure and total energy expenditure at age 91-96 years

There is a limited knowledge concerning energy requirements of the elderly, especially the oldest old (> 80 years). Energy requirements should be estimated from measurements of energy expenditure. For this purpose twenty-one free-living individuals (eight males, thirteen females) aged 91-96 years living in G?teborg, Sweden were studied. Total body water (TBW) measured by the doubly-labelled-water (DLW) technique was 29.5 (sd 5.4) kg in females and 35.6 (sd 4.3) kg in males. TBW measured using bioelectric impedance (BIA) was 31.6 (sd 6.4) kg in females and 42.0 (sd 7.4) kg in males. The mean difference between TBW measured by BIA and that measured by DLW was 3.54 (sd 3.6) kg (P = 0.0002). Resting metabolic rate (RMR) was measured using a ventilated-hood system and averaged 5.36 (sd 0.71) MJ/d in females (n 12) and 6.09 (sd 0.91) MJ/d in males (n 8). Difference between measured RMR and predicted BMR (n 20) was 0.015 (sd 0.86) MJ/d (NS). Total energy expenditure (TEE) measured by DLW averaged 6.3 (sd 0.81) MJ/d in females and 8.1 (sd 0.73) MJ/d in males. Activity energy expenditure (TEE - RMR), thus including diet-induced thermogenesis (DIT), averaged 0.95 (sd 0.95) MJ/d in females (n 12) and 2.02 (sd 1.13) MJ/d in males. Physical activity level (TEE/BMR) averaged 1.19 (sd 0. 19) in females and 1.36 (sd 0.21) (P = 0.08) in males. If DIT is assumed to be 10 % of the TEE, energy spent on physical activity will be very low in this population.     

The effect of physical activity on body fatness in children and adolescents

With the increasing prevalence of childhood obesity, there is an urgent need to identify risk factors that are amenable to preventative action. However, there is a remarkable lack of consistency between studies that have investigated the relationships between measurements of physical activity and energy expenditure and body fatness in children. This disparity could be because energy intake is a more important determinant in preventing obesity. Alternatively, some of the conflicting results could be related to methodological limitations in assessing activity and body composition. Erroneous conclusions may be drawn if physical activity energy expenditure is not adjusted for differences in body composition, or body fat is not appropriately adjusted for body size. For public health purposes it may be more informative to evaluate the amount and intensity of physical activity required to prevent fat-mass gain than to assess energy expended in physical activity. The lack of consensus in the cut-off points applied to define intensity levels is severely hindering comparisons between studies using accelerometers that have examined relationships between activity intensity and body fatness. Thus, it is not currently possible to develop a firm evidence base on which to establish physical activity recommendations until the limitations are addressed and more prospective studies undertaken. In order to turn research into effective prevention strategies a clearer understanding of the psycho-social, behavioural and environmental factors that influence activity is needed, including the interactions between physical activity and other behaviours such as time spent sedentary, sleeping and eating.     

Blood pressure differences between blacks and whites in relation to body size among US children and adolescents

No large national studies of ethnic differences in blood pressure among children accounting for body size differences have been published, to the authors' knowledge. This report details the similarities and differences in systolic and diastolic blood pressures between Black children and White children in the United States and examines the effects of age, sex, and body size on ethnic differences in blood pressure levels. Standardized measurements of seated systolic and diastolic pressures from eight large epidemiologic studies published between 1978 and 1991 that included measurements of 47,196 children on 68,556 occasions for systolic pressure and for 38,184 children on 52,053 occasions for diastolic pressure were used; 51 percent (24,048 children) were boys and 37 percent (17,466 children) were Black. Overall, there appear to be few substantive ethnic differences in either systolic or diastolic pressure during childhood and adolescence. The differences that were observed were small, inconsistent, and often explained by differences in body size. There was an ethnic group-body mass index (BMI) interaction that resulted in these findings that at lower levels of BMI Blacks have higher blood pressure and more hypertension than do Whites, but that at the highest levels of BMI, Whites have more hypertension (systolic or diastolic pressure) than do Blacks.     

Relation between physical activity and energy expenditure in a representative sample of young children

BACKGROUND: Strategies for the prevention and treatment of childhood obesity require a better understanding of the relation between the pattern of free-living physical activity and total energy expenditure (TEE). OBJECTIVE: We assessed the relations between TEE and physical activity level (PAL) during engagement in different intensities of physical activity. DESIGN: We used a cross-sectional study of 104 children (median age: 5.4 y) in Scotland. TEE was measured with use of doubly labeled water (DLW), and resting energy expenditure was predicted to determine PAL. Time spent sedentary and in light-intensity activity and in moderate- and vigorous-intensity physical activity (MVPA) was assessed by accelerometry concurrent with DLW measurements. Correlation and regression were used to assess the relations between measures of sedentary behavior, intensities of activity, and PAL as the dependent variable. RESULTS: Time spent sedentary was negatively correlated with PAL (r = -0.33, P < 0.01), and time spent in light-intensity activity was positively correlated with PAL (r = 0.31, P < 0.01). In multiple regression analyses, both time spent sedentary and in light-intensity activities were significantly associated with PAL. Time spent in MVPA was not associated with PAL; engagement in MVPA was limited in this sample (median: 3% of waking hours; range: 0-14%). PAL was significantly higher in boys than in girls. CONCLUSION: In this sample and setting, PAL was not influenced by engagement in MVPA but was influenced by time spent sedentary and in light-intensity activities. This study suggests that in young children, MVPA could make only a minor contribution to free-living TEE and PAL.     

Surveillance to improve physical activity of children and adolescents

The global transition to current low levels of habitual physical activity among children and adolescents began in the second half of the last century. Low physical activity harms health in both the short term (during childhood and adolescence) and long term (during adulthood). In turn, low physical activity could limit progress towards several sustainable development goals, undermine noncommunicable disease prevention, delay physical and mental health recovery from the coronavirus disease 2019 pandemic, increase health-care costs and hinder responses to climate change. However, despite the importance of physical activity, public health surveillance among children and adolescents is very limited globally and low levels of physical activity in children is not on the public health agenda in many countries, irrespective of their level of economic development. This article details proposals for improvements in global public health surveillance of physical activity from birth to adolescence based on recent systematic reviews, international collaborations and World Health Organization guidelines and strategies. Empirical examples from several countries illustrate how improved surveillance of physical activity can lead to public health initiatives. Moreover, better surveillance raises awareness of the extent of physical inactivity, thereby making an invisible problem visible, and can lead to greater capacity in physical activity policy and practice. The time has arrived for a step change towards more systematic physical activity surveillance from infancy onwards that could help inform and inspire changes in public health policy and practice globally.     

Physical activity energy expenditure in Dutch adolescents: contribution of active transport to school, physical education, and leisure time activities

BACKGROUND: Detailed knowledge about physical activity energy expenditure (PAEE) can guide the development of school interventions aimed at reducing overweight in adolescents. However, relevant components of PAEE have never been objectively quantified in this population. This study investigated the contribution of active transport to and from school, physical education (PE), and leisure time activities to total PAEE during a regular school week in adolescents. METHODS: Seventy‐three adolescents (mean age: 15.7 years) wore an individually calibrated combined heart rate‐acceleration monitor and kept an activity diary during a regular school week. Branched equation modeling was used to calculate PAEE of the specific activity categories, and their relative contribution to total PAEE was determined. RESULTS: Active transport and PE contributed 30.0% and 17.4%, respectively, to school‐related PAEE. Active transport to and from school contributed 15% to total PAEE. Youth with a high physical activity level (PAL) spent 4 hours less in sedentary behavior than subjects with a medium or low PAL (F = 77.415 (2.70), p < .001) and had higher PAEE during leisure time sports (F = 9.135 (2.70), p < .001) and work‐related activities (F = 10.583 (2.70), p < .001) than youth with medium or low PAL values. CONCLUSIONS: Active transport and PE contribute significantly to PAEE during school hours in adolescents. To achieve an increase in total PAEE in the least active group of adolescents, promising strategies might be to reduce inactive behavior, increase participation in leisure time sports, and possibly to replace inactive for active jobs.     

Physical activity energy expenditure predicts changes in body composition in middle-aged healthy whites: effect modification by age

BACKGROUND: It is unclear whether physical activity energy expenditure (PAEE) predicts changes in body composition. OBJECTIVE: The objective was to describe the independent associations between PAEE and changes in body composition in a population-based cohort. DESIGN: This was a prospective population-based study conducted in 739 (311 men and 428 women) healthy middle-aged (median age: 53.8 y) whites. The median follow-up was 5.6 y. PAEE (MJ/d) was assessed by heart rate monitoring, individually calibrated by using the FLEX heart rate method. Fat mass (FM) and fat-free mass (FFM) were assessed by bioimpedance. RESULTS: Body weight (BW) at follow-up was significantly related to baseline PAEE (P < 0.05) after adjustment for sex, baseline age, FM, FFM, and follow-up time. A significant interaction between PAEE and age (P = 0.023) was observed. After the subjects were stratified (above and below the median for age), BW increased by a mean (+/-SD) of 1.7 +/- 5.9 kg (P < 0.0001) in the younger cohort. In this group, follow-up FM was significantly associated with baseline PAEE (P = 0.036) after adjustment for confounders. In the older cohort, BW did not change between baseline and follow-up. In this group, in contrast with the younger population, follow-up BW, FM, and FFM were all significantly and positively associated with baseline PAEE (P < 0.01 for all). CONCLUSIONS: Baseline PAEE predicts a change in FM in younger adults, who as a group gained weight in this study. In contrast, baseline PAEE in older adults--who were on average weight stable--is associated with a gain in BW, which was explained by an increase in FM and FFM.     

The extent to which breakfast covers the morning energy expenditure of adolescents with varying levels of physical activity

BACKGROUND: Energy intake at breakfast affects the performance of creativity tests, memory recall and voluntary physical endurance in children before lunch, and food craving during the whole day. OBJECTIVES: To assess the adequacy of breakfast energy supply (BES) and energy expenditure (EE) in adolescents during a schoolday without or with 2 h of physical education lesson (PEL) in the morning. DESIGN: Sixty adolescents (four groups of 14-16 boys and girls aged 12-16 y) participated in a cross-sectional study. Activity patterns and EE were determined by whole-body calorimetry during 36 h and in free-living conditions during 5 days using both a diary and the validated heart rate recording method. BES was determined by weighing individual foods. The pyloric energy flow was assessed using a model of fractional stomach emptying. RESULTS: BES averaged 24.9% (s.d.=6.1) of daily EE in the four groups of subjects. It covered the mean morning EE on a schoolday without PEL, but not in a schoolday with 2 h of PEL in any group. When PEL took place from 8-10 am the cumulative EE exceeded the cumulative pyloric energy flow after 105-150 min, that is during the PEL session, and the energy deficit increased until lunch. With a light breakfast (BES-1 s.d.) energy deficiency happened after 90 min. CONCLUSION: The results stress the need for a heavy breakfast for children and adolescents on the days with PEL in the morning, and a carbohydrate rich snack at 10 am to improve attention, memory and willing participation in physical activities.     

艾滋病/性病/安全性行为同伴教育项目评价设计

  目的  探讨饮食知识健康教育和运动干预方式对中国城市初中生体质指数（BMI）和肥胖水平的干预效果,为青少年肥胖控制提供科学依据。  方法  于2015年9月,在天津、内江、大连抽取初一和初二1 491名学生作为研究对象,随机分为干预组（720人）和对照组（771人）,对干预组进行综合干预（健康教育和运动干预）,对照组进行普通干预（发放健康手册和知识讲座）,为期10月,干预前后分别进行问卷调查和体格测量。  结果  干预组肥胖学生BMI由干预前的30.1 kg/m² 下降为28.9 kg/m²,对照组肥胖学生BMI由干预前的29.9 kg/m² 下降为29.4 kg/m²,干预组肥胖学生BMI下降显著高于对照组。其中,干预组肥胖男生BMI由干预前的30.0 kg/m² 下降为28.6 kg/m²,对照组肥胖男生BMI由干预前的29.5 kg/m² 下降为28.9 kg/m²,干预组肥胖男生BMI下降显著高于对照组（P < 0.05）;在肥胖女生中干预不显著（P > 0.05）。干预组学生工作日久坐行为时间由干预前的4.2 h下降为4.1 h,对照组学生干预前后均为4.4 h;干预组学生每周吃水果蔬菜天数由干预前的4.5 d增加为5.1 d,对照组学生干预前后均为4.8 d,2组比较差异有统计学意义（P < 0.05）。  结论  健康教育和运动干预相结合有助于提高学生体力活动水平,明显降低肥胖学生尤其是男生肥胖水平,但干预效果仍存在性别差异。     

Intergenerational differences in food, physical activity, and body size perceptions among African migrants

We assessed intergenerational differences in food, physical activity, and body size perceptions among refugees and migrants from the Horn of Africa living in Victoria, Australia. We used a qualitative design and obtained data from 48 participants (18 individual interviews; 3 semistructured focus groups). Three major themes emerged: (a) food and physical activity, (b) preference of body size and social expectations, and (c) perceived consequences of various body sizes. For parents, large body size was perceived to equate with being beautiful and wealthy; slimness was associated with chronic illness and poverty. Parents adopted strategies that promoted weight gain in children. These included tailored food practices and restricting children's involvement in physical activity. For young people, slimness was the ideal body size endorsed by their peers, and they adopted strategies to resist parental pressure to gain weight. Obesity-prevention programs in this subpopulation need to adopt a multigenerational approach.