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1.
OBJECTIVE: To study the effect of body composition on average daily metabolic rate (ADMR) and basal metabolic rate (BMR) in adolescence, and to examine current BMR prediction equations. STUDY: Dutch adolescents were pooled with previously reported American and British subjects (n = 90 overall). BMR and ADMR were analysed by multiple regression. RESULTS: Fat-free mass, BMR, and ADMR were higher in the obese than in the non-obese group (mean (SD): 53.2 (10.7) kg, 8.35 (1.57) MJ/d, and 13.64 (2.78) MJ/d, compared with 41.0 (8.1) kg, 6.42 (0.94) MJ/d, and 11.16 (2.21) MJ/d, respectively). BMR remained higher when adjusted for fat-free mass, age, and sex. ADMR adjusted for BMR was similar in the two groups. WHO equations overestimated BMR in obese boys and underestimated BMR in non-obese boys. CONCLUSIONS: BMR, but not activity, is increased in obese adolescents and in male adolescents. The WHO BMR equations for adults are recommended for obese adolescents.  相似文献   

2.
OBJECTIVE—To study the effect of body composition on average daily metabolic rate (ADMR) and basal metabolic rate (BMR) in adolescence, and to examine current BMR prediction equations.STUDY—Dutch adolescents were pooled with previously reported American and British subjects (n = 90 overall). BMR and ADMR were analysed by multiple regression.RESULTS—Fat-free mass, BMR, and ADMR were higher in the obese than in the non-obese group (mean (SD): 53.2 (10.7) kg, 8.35 (1.57) MJ/d, and 13.64 (2.78) MJ/d, compared with 41.0 (8.1) kg, 6.42(0.94) MJ/d, and 11.16 (2.21) MJ/d, respectively). BMR remained higher when adjusted for fat-free mass, age, and sex. ADMR adjusted for BMR was similar in the two groups. WHO equations overestimated BMR in obese boys and underestimated BMR in non-obese boys.CONCLUSIONS—BMR, but not activity, is increased in obese adolescents and in male adolescents. The WHO BMR equations for adults are recommended for obese adolescents.  相似文献   

3.
Exercise capacity and the causes of its limitation following repair of tetralogy of Fallot have been studied in heterogeneous populations. Study populations have been grouped together regardless of the type of repair and residual hemodynamic abnormalities. To better understand the factors limiting aerobic exercise capacity in patients repaired with a transannular patch, 37 patients with a transannular patch and no residual pulmonary stenosis underwent resting spirometry and treadmill exercise testing. Maximal oxygen consumption and oxygen consumption at anaerobic threshold were measured in all patients to assess aerobic capacity. Patients were subdivided by gender. Resting spirometry measurements tended to be lower in both genders compared to healthy controls but did not correlate with any measurement of aerobic capacity. Maximal oxygen consumption and anaerobic threshold were significantly less in the female than the male population. A quadratic relation between maximal oxygen consumption and age at exercise testing existed for both genders but peaked at an earlier age and was significantly less in the female population. There was a significant negative correlation between maximal oxygen consumption and echocardiographically estimated right ventricular inflow volume index in the female population only. These data suggest that in patients with tetralogy of Fallot repaired with a transannular patch aerobic capacity is limited primarily by cardiac function, but that gender differences are due to noncardiac causes.  相似文献   

4.
Effects of obesity on aerobic fitness in adolescent females   总被引:1,自引:0,他引:1  
Obesity impairs performance in most athletic events, but the influence of increased body fat on cardiopulmonary function has not been clearly delineated. An understanding of the fatness-fitness relationship is important in the optimal design of exercise programs for obese subjects. In this study, 27 adolescent females with body fat levels ranging from normal to gross obesity were evaluated to determine the impact of adiposity on physiologic factors during maximal and submaximal treadmill walking. Increased skinfold measures correlated significantly with absolute maximal oxygen uptake throughout the range of body fat levels (r = .72), and oxygen consumption per kilogram of body weight and treadmill endurance time both declined as fatness increased (r = -.49 and -.42, respectively). Obesity did not affect submaximal walking economy. These findings indicate that increased fat levels are associated with increased cardiopulmonary exercise capacity, but that functional fitness declines because of the inert load created by excess body fat. Therefore, therapeutic exercise programs for obese adolescents are best designed to increase caloric expenditure and decrease body fat rather than to improve aerobic fitness.  相似文献   

5.
AIM: To fight overweight and obesity in childhood, this study proposes an additional physical activity (PA) in young children aged 6-10 years. The objective was to evaluate the effect of school-based PA on the body composition according to body mass index (BMI) categories (nonobese vs. obese) and gender. METHODS: This 6-month study examined the effect of this intervention on body composition in 425 children in 14 primary schools (2 weekly PA sessions of 1 h each) compared to 5 control schools. Adiposity indices were evaluated or calculated: BMI, BMI z-score, waist circumference, sum of skinfolds and fat-free mass. RESULTS: No difference in the prevalence of obesity and anthropometric characteristics was found between the intervention and control groups at baseline. In girls, PA intervention had significant effect on all anthropometric variables (p < 0.05 to p < 0.001), except on BMI. In contrast, in boys only BMI z-score (p < 0.001) and fat-free mass (p < 0.001) were affected. CONCLUSIONS: Six months of preventive PA intervention offer an effective means to improve body composition in obese children. The pattern of response related to PA was similar between girls and boys. In contrast, the pattern was different according to BMI category, with a higher response in obese than nonobese children.  相似文献   

6.
Aerobic capacity in late adolescents infected with HIV and controls   总被引:3,自引:0,他引:3  
OBJECTIVES: The objective of this study was to determine if aerobic capacity was diminished in late adolescents infected with HIV compared to controls matched for age, gender, and physical activity level. STUDY DESIGN: This study was a quasi-experimental cross sectional analysis. Subjects (11 female, four male) were 15 late adolescents with HIV (18 +/- 0.03 years) (CD4: 499.2 +/- 37.5 cells/mm(3), viral load: 22043 +/- 9976.6 copies/ml, haematocrit: 36.4 +/- 1.2) and 15 age, gender, and activity level matched controls (18 +/- 0.03) who underwent maximal treadmill exercise testing, while oxygen consumption, carbon dioxide production, ventilation, and ECG data were simultaneously recorded via open circuit spirometry and electrocardiography. RESULTS: Peak oxygen consumption (p < 0.003), peak treadmill stage (p < 0.003), treadmill duration (p < 0.004), and oxygen pulse (p < 0.009) were lower in those infected with HIV compared to controls. Functional aerobic impairment was observed in the late adolescents infected with HIV, pointing toward pathological limitations of the oxidative metabolic pathway. CONCLUSION: This study has demonstrated that aerobic capacity was reduced substantially in late adolescents infected with HIV, below that observed in controls. The findings suggest that this decrease in oxidative capacity was due to mechanisms other than physiologic deconditioning.  相似文献   

7.
OBJECTIVES: To investigate 24-hour ambulatory blood pressure, lipid profiles, and carotid artery intimal-medial thickness (IMT) in adolescents with and without obesity. STUDY DESIGN: Ambulatory blood pressure data from 93 consecutive adolescents referred to our hypertension center for possible hypertension were analyzed. Fasting serum glucose and lipid concentrations were measured in all subjects. Carotid artery IMT was also measured by B-mode ultrasound imaging in all patients. Obesity was defined as body mass index > or =95(th) percentile for age and sex. Twenty-two of the subjects were obese and 71 nonobese. RESULTS: Mean 24-hour, daytime, and nighttime systolic blood pressures were significantly higher in obese subjects compared with nonobese subjects (P < .002). Twenty-four-hour, daytime, and nighttime pulse pressures were also significantly higher in obese subjects (P < .001). The magnitude of systolic white coat effect was significantly higher in obese subjects (P < .006) and white coat hypertension was significantly more frequent in obese subjects (P < .0001). Obese subjects had higher triglycerides (P < .001) and lower HDL cholesterol (P < .01) than nonobese subjects. Finally, obese adolescents had thicker mean IMT of internal carotid arteries than nonobese adolescents (P < .005). CONCLUSIONS: Obese adolescents have higher ambulatory blood pressure and higher carotid artery IMT, possibly indicating an early course of obesity-related hypertension and carotid artery structural alterations.  相似文献   

8.
OBJECTIVE: To determine the response to maximal treadmill exercise with the Bruce protocol in a cohort of healthy non-obese American children and adolescents. STUDY DESIGN: A retrospective review of treadmill exercise studies on 347 white American children (188 boys, 159 girls) aged 5 to 18 years was performed with metabolic criteria to verify maximal exercise effort. Data on exercise endurance time, heart rate, blood pressure, and metabolic variables were assessed and compared between age groups and sexes by unpaired t testing and analysis of variance. RESULTS: Exercise endurance time was lower in all age groups when compared with earlier published data. Girls had a lower endurance time than boys at all ages. There was no significant difference in maximum heart rate with respect to age or sex. The maximum systolic blood pressure and diastolic blood pressure increased with increasing age in both boys and girls. Boys had significantly higher maximum systolic blood pressure and diastolic blood pressure after 13 years of age. The maximum absolute oxygen consumption and indexed oxygen consumption showed similar trends for both sexes. CONCLUSION: Lower exercise endurance times are seen despite physiologic evidence of maximal effort, raising the possibility that cardiovascular conditioning is reduced in contemporary American children.  相似文献   

9.
We measured the effect of an aerobic exercise session on postprandial glucose control in adolescents with habitually low‐physical activity. The goal was to determine if the acute or residual response of exercise was altered in people who are overweight/obese (OW/Ob). Eleven normal weight, body mass index (NW, BMI = 48 ± 13 percentile) and 12 OW/Ob (BMI = 91 ± 5 percentile) participants completed 3 trials. In the no exercise (No Ex) trial, participants rested quietly before and after consuming a test meal. In the other 2 trials, a 45‐minute aerobic exercise session was performed either 17‐hour (Prior Day Ex) or 40 minutes (Same Day Ex) before the test meal. On all trials, the OW/Ob group had higher fasting glucose (~6%) and insulin (~66%), and lower insulin sensitivity (~9%) than the NW group. The Same Day Ex and Prior Day Ex trials resulted in reduced area under the curve for glucose (6% on both trials, P < .01) and insulin (15% and 13%, respectively, P < .03), and increased insulin sensitivity (8% and 6%, respectively, P < .01). The magnitudes of those effects did not differ between the NW and OW/Ob groups. Plasma fatty acids declined and carbohydrate oxidation increased after the meal, but did not differ among trials or groups. The results demonstrate that moderate intensity aerobic exercise increases insulin sensitivity in NW and OW/Ob adolescents and that the beneficial effects of exercise last up to 17 hours. The acute impact of exercise on metabolic health in adolescents is not impaired in overweight/obese participants.  相似文献   

10.
We assessed relative bone mineral content (BMC) in normal-weight (BMI < 85th percentile), overweight (BMI ≥ 85th---< 95th percentile), and obese (BMI ≥ 95th percentile) adolescents and evaluated the impact of nonweight bearing stationary cycle exercise training in a subset of obese participants. Obese and overweight adolescents had higher (p = .001) BMC than normal-weight counterparts, but after adjusting for total body mass the overweight and obese adolescents had a significantly lower (p < .001) BMC than normal-weight subjects. Although aerobic training such as cycling would seem optimal for caloric expenditure in obese adolescents, this study showed that eight weeks of cycle training did not improve BMC in obese adolescents. Weight-bearing aerobic exercise would be a better option for optimizing bone health in this population.  相似文献   

11.
ABSTRACT. The functional and dimensional components of the oxygen transporting system was studied in 17 female and 11 male patients suffering from anorexia nervosa. Both groups were 14.9 years old, on average, and had lost about 25% of their weight. Measurements at rest included blood and heart volume, heart rate, blood pressure, oxygen uptake ( V o2), RQ, blood lactate (LA) and in 6 of the patients cardiac output. During bicycle ergometry the determinations of heart rate, blood pressure, LA, V o2 and cardiac output were repeated and maximal aerobic power was determined. A low metabolic rate with bradycardia and hypotension was apparent at rest. Blood and heart volume was decreased proportionally to the weight loss. On a given work load V o2 was lowered to the same extent as the resting metabolic rate. At maximal effort V o2 was reduced out of proportion to the circulatory dimensions and maximal heart rate was low. During exercise cardiac output was normally related to V o2 and stroke volume was maintained, indicating a normokinetic circulation and an unimpaired myocardial function. The main cause of the low maximal aerobic power seems to be the reduced muscle mass.  相似文献   

12.
We estimated the metabolic rate of 13 low birth weight infants over a 9-day period, using indirect calorimetry in conjunction with serial measurements of oxygen consumption, carbon dioxide production, and total urinary nitrogen excretion. The mean percent error for oxygen consumption and carbon dioxide production measurements (determined by alcohol combustion experiments) assignable to the open-circuit system was 0.4 and 3.8%, respectively. Error in the total urinary nitrogen excretion measurement was less than 1% by the Kjeldahl technique. In the clinical setting, however, the range of deviation of measured oxygen consumption, carbon dioxide production and total urinary nitrogen excretion was +/- 12, 12, and 15% of the mean value respectively for an individual patient under standardized controlled conditions. The variability of metabolic rate between infants may be as much as 76%. Factors that had a small effect on metabolic rate were difficult to detect because of the variability inherent in the short-term measurement of metabolic rate. It was virtually impossible to control the sources of variation in the resting metabolism of low birth weight neonates over extended experimental periods. Day-to-day variations in resting energy expenditure may explain, in part, the widely different growth rates of premature infants receiving similar caloric intakes.  相似文献   

13.
Aim: Although obesity and weight gain generally are anticipated to be caused by an imbalance between energy intake and energy expenditure, the significance of thyroid hormones (TH) remains unclear. Examination of mitochondrial function may reflect intracellular thyroid hormone effect and elucidate whether a lower metabolic rate is present. Methods: In a group of 34 obese adolescents (age <16 years and body mass index above the age‐related 95th percentile), and an age‐ and gender‐matched group of 32 lean adolescent, thyroid stimulating hormone (TSH) and basal oxygen consumption were measured and mitochondrial function in peripheral blood monocytes was determined by flow cytometry. Results: Significant increase in TSH (3.06 ± 1.56 mU/L vs. 2.33 ± 0.91 mU/L, p < 0.05) and a decrease in VO2 (129 ± 16 mL O2/m2*min vs. 146 ± 15 mL O2/m2*min, p < 0.05) were observed in obese adolescents compared with lean adolescents. Flow cytometry analysis demonstrated a lower mitochondrial mass (6385 ± 1962 a.u. vs. 7608 ± 2328 a.u., p < 0.05) and mitochondrial membrane potential (11426 ± 3861 a.u. vs. 14017 ± 5536 a.u., p < 0.05) in obese adolescents compared with lean adolescents. These results are even more pronounced in adolescents with obese mothers. Conclusion: In obese adolescents, the increased TSH and lowered VO2 propose a lowered basal metabolic rate and the impaired mitochondrial function suggests a decreased thyroid hormone stimulation of mitochondrial energy production. The maternal in‐heritage is suggestive of a basal metabolic defect or mitochondrial resistance for TH.  相似文献   

14.
The purpose of this study was to describe changes in fat mass (FM), fat-free mass (FFM) and aerobic fitness in severely obese children and adolescents during residential treatment in the Medical Paediatric Centre Zeepreventorium. Treatment consisted of moderate dietary restriction, physical activity and psychological support. This study was a clinical observation of 20 severely obese children and adolescents (8 boys and 12 girls, aged 15.4+/-1.8 years) who completed the 10-month residential programme. Height, weight, FM, FFM and aerobic fitness was measured four times during the intervention: at baseline, 11 weeks, 24 weeks and at 33 weeks (at the end of the programme ). The mean decrease in level of overweight was 46% (P<0.001), with a mean loss of 8.9% FM (P<0.001). Submaximal performance (PWC150) improved from 123+/-35 Watt to 152+/-37 Watt (P<0.001). Maximal performance levels increased (performance time: from 14+/-2.9 min to 15.3+/-3.5 min, peak power: from 186+/-38 Watt to 205+/-45 Watt, P<0.01) without an improvement in absolute VO(2 peak). CONCLUSION: A moderate dietary restriction in combination with physical activity and psychological support in severely obese children and adolescents is effective in decreasing body fat and improving physical performance. Further research is needed to evaluate the longer-term effects of such a programme.  相似文献   

15.
OBJECTIVE: To study the relationship of fat mass, extracellular-to-intracellular-water ratio, and bone mineral density with growth hormone function and physical activity in Prader-Willi syndrome. STUDY DESIGN: There were 17 patients with PWS (10 women, ages 7.5-19.8 years) and 17 obese control patients, matched for gender and bone age. FM and extracellular-to-intracellular-water ratio were measured by bromide-deuterium dilution, BMD by dual-energy x-ray absorptiometry, GH function by fasted serum insulin-like growth factor-I concentration, and physical activity by doubly-labeled water in combination with basal metabolic rate by a ventilated hood. RESULTS: The PWS group had a similar fat mass, but a lower fat-free mass, whereas the extracellular-to-intracellular-water ratio was higher compared with the control group (0.87 +/- 0.07 l/l and 0.80 +/- 0.06 l/l, respectively [P <.01]). Fat mass was inversely related with PA in the PWS group, whereas IGF-I was positively correlated with FFM, ICW, and BMD of the limbs. BMD tended to be lower in patients with PWS. CONCLUSIONS: In children and adolescents with PWS, adiposity is associated with a reduced fat-free mass and extracellular-to-intracellular-water ratio is increased. Both findings are related to GH function and physical activity. BMD, especially in the limbs, tends to be reduced in patients with PWS and is related to GH function.  相似文献   

16.
We measured body composition, resting metabolic rate (RMR), and total energy expenditure (TEE) in a group of adolescents with cerebral palsy (CP) and myelodysplasia (M) aged 13- to 20-y-old using indirect calorimetry and the doubly labeled water method. Fat-free mass (FFM), RMR, and TEE were significantly lower in both the CP and M groups than comparable measurements in a control group of normal adolescent males and females. The ratio of TEE to RMR did not differ between controls and ambulatory M and CP subjects. However, TEE/RMR was significantly lower in the nonambulatory M and CP subjects than in controls (p less than 0.01). Our data indicate that energy requirements are reduced in both populations because both FFM and activity are decreased. Although energy requirements were decreased in both groups, the relationships between FFM and body weight differed. FFM and body weight were significantly correlated with RMR only in the M group. These data suggest that the type of paralysis in a handicapped population may affect resting energy expenditure.  相似文献   

17.
Aim: The aim of this study was to identify relationships between insulin sensitivity (SI), cardiorespiratory fitness and body composition in severely obese Swedish children and adolescents.
Methods: Two hundred and twenty-eight obese children (119 girls, 8–16 years, body mass index (BMI) 23.2–57.0 kg/m2) performed a frequently sampled intravenous glucose tolerance test (FSIVGTT), a submaximal bicycle ergometry test and a dual-energy X-ray absorptiometry (DEXA).
Results: Mean SI (SD) was 0.38 (0.32) (×10−5/min/pM). SI correlated positively with relative body mass (BM) VO2max (r = 0.42) (p < 0.001), relative fat-free mass (FFM) VO2max (r = 0.36) (p < 0.001) and negatively with body mass index standard deviation score (BMI SDS) (r =−0.22) (p = 0.001). SI did not correlate with percent body fat (r =−0.01) and absolute VO2max (r = 0.01). In multiple regression analyses with SI as dependent variable, VO2max and body composition, together with gender, age and Tanner stage, explained 20–26% of the variance.
Conclusion: Relative (BM) VO2max and relative (FFM) VO2max were stronger predictors of SI than percent body fat in severely obese children and adolescents. The study confirms that cardiorespiratory fitness is of importance for the metabolic syndrome in the studied population. Efforts to improve SI should include physical activity targeting cardiorespiratory fitness also in severely obese children and adolescents.  相似文献   

18.
During puberty fat-free mass (FFM) and fat mass (FM) change quickly and these changes are influenced by sex and obesity. Since it is not completely known how these changes affect resting metabolic rate (RMR), the aim of the present study was to investigate the effect of body composition, age, sex and pubertal development of postabsorptive RMR in 9.5- to 16.5-year-old obese and non-obese children. Postabsorptive RMR was measured in a sample of 371 pre- and postpubertal children comprising 193 males (116 non-obese and 77 obese) and 178 females (119 non-obese and 59 obese). RMR was assessed by indirect calorimetry using a ventilated hood system for 45 min after an overnight fast. Body composition (FFM and FM) was estimated from skinfold measurements. The mean (± SD) RMR was significantly (P < 0.001) lower in non-obese (males: 5600 ± 972 kJ/24h; females: 5112 ± 632 kJ/24h) than in obese (males: 7223 ± 1220 kJ/24h; females: 6665 ± 1106 kJ/24h) children. This difference became non-significant when RMR was adjusted for body composition (FFM + FM). However, the difference between the genders still remained significant (control male: 6118 ± 507, control female: 5652 ± 507, P < 0.001; obese male: 6256 ± 507, obese female: 5818 ± 507 kJ/24h, P < 0.001). The main determinant of RMR was FFM. In the whole cohort, FFM explained 79.8% of the variation in RMR, followed by age, gender and FM adding further 3.8%, 1.1% and 0.8% to the predictability of RMR, respectively. No significant contribution for study group (obese, non-obese), pubertal stage, or fat distribution was found in the regression for RMR. The adjusted value of RMR (for FFM and FM) slightly, but significantly (P < 0.01) decreased between the age of 10–16 years, demonstrating the important effect of age on RMR. Conclusions The resting metabolic rate of obese and control children is not different when adjusted for body composition. The main determinant of RMR is the fat-free mass, however, age, gender and fat mass are also significant factors. Pubertal development and fat distribution do not influence RMR independently from the changes in body composition. Received: 4 March 1996 / Accepted: 21 August 1996  相似文献   

19.
Measurements of cardiorespiratory function during an incremental treadmill test were compared in 15 obese (OB) prepubescent girls, 7 to 12 years old, and in 15 age-matched, nonobese (NOB) controls. Open circuit calorimetry was used for data collection during the progressive work test. Maximal oxygen consumption indexed for weight was significantly lower in the obese group of girls (23.0 +/- 3.9 ml/kg/min) than in the nonobese controls (36.7 +/- 0.9 ml/kg/min). In addition, exercise tolerance was longer in the nonobese group, albeit not statistically significant. In conclusion, diminished cardiopulmonary performance and attenuated exercise tolerance in prepubescent obese females in the current investigation seemed to be influenced by excess body weight.  相似文献   

20.
This study aimed to assess the effects of a 2-month lifestyle modification trial on cardio-metabolic abnormalities and C-reactive protein (CRP) among obese adolescents with metabolic syndrome [phenotypically obese metabolically abnormal (POMA)] and obese adolescents without a cardio-metabolic disorder [phenotypically obese metabolically normal (POMN)], as well as in normal-weight adolescents with at least one cardio-metabolic disorder [phenotypically normal metabolically obese (PNMO)]. The study comprised 360 adolescents assigned in three groups of equal number of POMN, POMA and PNMO. They were enrolled in a trial consisting of aerobic activity classes, diet and behaviour modification, and were recalled after 6 months. Overall, 94.7% of participants completed the 2-month trial, and 87.3% of them returned after 6 months. The mean CRP was not significantly different between the POMA and PNMO groups, but was higher than in the POMN group. After the trial, body mass index (BMI) and waist circumference (WC) decreased in obese participants, and the mean body fat mass decreased in all groups. At 2 months, the mean total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG) and CRP decreased in the POMA and PNMO groups. After 2 and 6 months, the decrease in mean TC, LDL-C, TG, CRP and systolic blood pressure was greater in the POMA than in the POMN group. The magnitude of decrease in CRP correlated with that of BMI, WC, fat mass, TG, TC and LDL-C. Lifestyle modification programmes for primordial/primary prevention of chronic diseases would be beneficial at the population level and should not be limited to obese children.  相似文献   

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