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close this bookBibliography of Studies of the Energy Cost of Physical Activity in Humans (London School of Hygiene & Tropical Medicine, 1997, 162 pages)
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View the document3. Children and adolescents
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View the document6. Review papers

3. Children and adolescents

1. Banerjee B & Saha N (1972): Energy intake and expenditure of Indian schoolboys. Br.J.Nutr. 27, 483-490.

Sixteen Indian schoolboys, aged 12-14 years and resident in Singapore, were tested for the determination of energy cost, pulmonary ventilation (PV) and oxygen (02) consumption at rest and at various daily activities; their height, body-weight, pulse and blood pressure were also measured. An energy balance study was made by estimating from a diary of measured activities the 24 h energy intake and output. PV and 02 consumption during running showed positive correlations (r=0.4 and r=0.3 respectively) with mean height and body-weight. High positive correlations (r=0.8) were obtained between mean post-excercise recovery pulse, 02 consumption and PV. The daily mean calorie intake and output of the subjects were found to be 2108 kcal (8.85 MJ) and 1811 kcal (7.60 MJ) respectively. The boys gained an average of 2.2 kg in weight and 0.7 cm in height in 2 months. They did not suffer from any mental retardation, they were physically fit, free from disease and did their daily routine work satisfactorily.

2. Banerjee B & Saha N (1982): Energy cost of some common physical activities of Chinese schoolboys. Ann.Nutr.Metab. 26, 360-366.

Fourteen Chinese schoolboys aged 12-14 years, resident in Singapore coming from affluent homes, were tested for the determination of energy cost, pulmonary ventilation (PV) and oxygen (02) consumption at rest and during some common physical activities by using a Max-Planck respirometer and Lloyds gas analysis apparatus. The study was undertaken for comparison with the results of a similar investigation of Indian schoolchildren of the same age-group living in a hostel under hostel discipline and diet in Singapore reported earlier. The energy cost (kcal/min, kJ/min) in these Chinese children was found to be significantly higher, but the energy cost per kilogram body weight per hour was found to be significantly lower than in the Indian children. PV in litres per minute was significantly higher in Chinese schoolboys during all physical activities except lying at rest, sitting and running. O2 consumption in litres per minute was also significantly higher during all activities except lying at rest and sitting.

3. Blackburn ML & Calloway DH (1974): Energy expenditure of pregnant adolescents. J.Am.Diet.Assoc. 65, 24-30.

Energy expenditure of female adolescents residing in a metabolic unit was measured at rest and during various household activities and standard work task performed during pregnancy and in some cases, postpartum. Diaries of daily activities were kept by a second, comparable group of free-living pregnant adolescents enrolled in a city high school program. Energy cost of activities measured in the first group was used to estimate the daily energy needs of the second group. Basal metabolic rate was 17% higher during the third trimester of pregnancy than postpartum, but there was no difference between the data if values were corrected for the difference in body weight. Energy expenditure per unit of mass was also the same for quiet sitting and standing activities during and after pregnancy. When work levels were heavier and involved body movement, work pace was slowed, and energy expenditure per unit of time was less during pregnancy than postpartum. Pace appeared to the dominant variable, since the cost of fixed work tasks (treadmill and bicycle) was the same per kilogram per minute during pregnancy and postpartum. The energy cost of a task, eg stair climb, was greater for the pregnant woman, in proportion to her increased body mass. Pregnant adolescents were extremely sedentary, spending about 90% of their time lying down or seated. Their average energy expenditure for basal metabolism and activity was computed to be 2,200 kcal per day. With a daily allowance of 150 kcal for deposition of maternal tissues and conceptus, total metabolizable energy need was about 2,400 kcal per day. If there were continued maternal growth, need would be increased proportionately.

4. Bradfield RB, Chan H. Bradfield NE & Payne PR (1971): Energy expenditures and heart rates of Cambridge boys at school. Am.J.Clin.Nutr. 24,1461-1466.

The energy expenditure of 54 primary school boys in Cambridge, England, was measured for 3 to 5 days during classes, and organized and unorganized play, using a technique that does not interfere with usual activities. The measurement of weight, height, and skin folds indicated the boys were on the high side of normal for both height and weight as judged by British standards. The central tendency of classroom activities was 2.1 to 2.7 kcal/min and the lunch play period 3.0 kcal/min. There was no significant difference between the energy expenditures of the fattest and leanest children of the group. The school program and types of games are described.

5. Bradfield RB, Paulos J & Grossman L (1971): Energy expenditure and heart rate of obese high school girls. Am.J.Clin.Nutr. 24,1482-1488.

The energy expenditure and physical activity of nonobese and obese high school girls participating in the same school program were assessed by three different methods over different periods of time. The continuous monitoring of heart rate and use of individual regressions of heart rate on oxygen consumption to estimate energy expenditure showed no significant differences between nonobese and obese girls during physical education classes, during school classroom activities, and after school work or play. Three-day activity assessments showed that both groups were very inactive, 70% of the time was spent either in sleep or very light activites. Assessment of relative participation in physical education class did not reveal different trends between obese and nonobese subjects.

6. Brooke OG, Alvear J & Arnold M (1979): Energy retention, energy expenditure, and growth in healthy immature infants. Pediatr.Res. 13, 215-220.

Energy balance studies were done during 10-29 days on 15 immature infants of mean birth weight 1581 9. Mean gross energy intake was 757 kJ/kg (181 kcal) and 79% of this was retained, so that metabolizable energy was 602 kJ/kg (143 kcal). Mean resting metabolic rate was 244 kJ/kg (58.1 kcal), and it increased with advancing maturity. Minimum resting metabolism averaged 199 kJ/kg (47.5 kcal). Energy expended in activity increased with maturity, but amounted to less than 17% of the total energy turnover. Postprandial metabolism caused the mean VO2 to rise by 17% in the hour after a feed, and during 24 hrs resulted in consumption of energy equivalent to about 10% of the resting metabolism. Stored energy amounted to 230 kJ/kg (55 kcal) and was linearly related to weight gain (r = 0.92). Energy cost of weight gain was 24 kJ/g (5.7 kcal) and energy stored in new tissue was 16.8 kJ/g (4.0 kcal). Maintenance energy requirement at zero growth rate was about 270 kJ/kg (64 kcal).

7. Chessex P. Reichman BL, Verellen GJ, Putet G. Smith JM, Heim T & Swyer PR (1981): Relation between heart rate and energy expenditure in the newborn. Pediatr.Res. 15, 10771082.

This study defines the relationship between heart rate and metabolic rate in newborn infants and evaluates the accuracy of prediction of metabolic rate from heart rate. Continuous measurements of oxygen uptake, CO2 production, respiratory quotient, and cumulative heart rate were performed using computerized, open-circuit indirect calorimetry and on-line electrocardiogram monitoring over periods of 1 to 24 hr (mean 4.5 fur). Metabolic rate was calculated from the individual oxygen uptake and respiratory quotient. Thirty-five studies were performed in 16 infants (birthweight 0.75 to 3.1 kg; gestational age, 26 to 42 wk; mean +/- S.D. age at study, 26.5 +/- 15.7 days; study weight, 1.78 +/- 0.5 kg). Metabolic rate (car/kg . min) and heart rate (beats/min) were compared minute by minute (8269 measurements) and showed a close third degree polynomial relationship for heart rates of 110 to 230/min (y = 0.0000291x3 + 0.01685x2 -2.93x + 197; r = 0.99; P less than 0.001); however, at heart rates above 140 beats/min, a linear relationship was found (r = 0.997; P less than 0.001). From cumulated heart rate measurements, factors defining metabolic rate per heart beat were also determined: for each beat 51.8 +/- 6.8 microliter of oxygen/kg are consumed and 0.258 +/0.03 car/kg (1.1 J/kg) are expended. Despite the wide variation in birthweight, gestational age, method of feeding, and clinical characteristics, there was a remarkable consistency in the heart rate-metabolic rate relationships. A further 10 studies were performed in a similar group of infants to assess the predictive value of the previously defined relationships and showed a mean percentage deviation of 5.7 +/- 4% from the measured value. It was concluded that in the varied group of newborns studied, heart rate correlates closely with metabolic rate and that cumulative heart rate measurements enable the estimation of metabolic rate in newborn infants. This provides a method of monitoring energy expenditure and caloric requirements over long periods.

8. Cooke CB, McDonagh MJ, Nevill AM & Davies CT (1991): Effects of load on oxygen intake in trained boys and men during treadmill running. .J.Appl.Physiol 71, 1237-1244.

Department of Sport and Exercise Sciences, University of Birmingham, United Kingdom. This investigation examines the effects of vertical and horizontal loading on the 02 intake (V02) response of children (n = 8) and adults (n = 8) to treadmill running. In unloaded running, the children required a significantly greater VO2 (P less than 0.001) than the adults [mean difference 7 (18.5%)]. There was no significant difference in the VO2 response of the children and the adults to either vertical or horizontal loading. Vertical loading with 5 and 10% of body mass did not produce a significant increase in the VO2 response of either group. In contrast, horizontal loading produced a significant increase (P less than 0.001) in both groups. The consistent response to the two forms of loading suggests that there is no difference between children and adults in the apparent efficiency of running with an external load. Stride frequency showed a significant increase with vertical loading (P less than 0.001) and a significant decrease with horizontal loading (P less than 0.001) in both groups.

9. Davies CT (1980): Metabolic cost of exercise and physical performance in children with some observations on external loading. Eur.J.Appl.Physiol 45, 95-102.

The metabolic cost (VO2) of running was studied on a motor-driven treadmill in nine athletic boys, five athletic girls, and nine active boys aged 11-15 years and the results compared with their performance times during racing out of doors. On 15 of the children additional observations of the effects of external loading on aerobic power output were made. The results showed that VO2 was proportional to body weight in children but when expressed, VO2 for a given speed of running was significantly higher in children than expected from previously collected data on adults. There were no significant differences between aerobic cost of running of the athletic boys, girls, or the active boys. The increased VO2 in children appeared to be independent of stride length and frequency but external loading equivalent to 5% of body weight reduced VO (, particularly at the higher speeds. It was suggested in young active and athletic children due to their relatively light body weights and highly developed aerobic power outputs, that the required frequency of leg movement was not optimally matched to the force necessary to produce the most economic conversion of aerobic energy into mechanical work. Thus, in competitive events their performance times were related to their maximal aerobic power output (r=-0.75) but their times were always inferior to those which one might have expected from previous aerobic power weight data collected on adult male and female athletes.

10. Devadas RP, Anuradha V & Mathai J (1977): Energy intake and expenditure of selected adolescent girls. Ind.J.Nutr.Diet. 14, 31-37.

The energy intake and expenditure of 12 adolescent Indian college girls were studied. Basal metabolic rate was between 31.59 and 55.80 kcal/m²h. Energy expenditure of girls residing in a hostel, 2843 kcal, was higher than that of girls staying with their families, 2642 kcal. Energy expenditure of both groups appeared to be higher than energy intake, 2460 and 2412 kcal daily

11. Duggan MB & Milner RDG (1986): The maintenance energy requirement for children: an estimate based on a study of children with infection associated to underfeeding. Am.J.Clin.Nutr. 43, 870-878.

An estimate of the maintenance energy requirement (MER) has been based on energy balance data from children fed at different levels of intake during and after acute measles. The relationship between apparent energy balance (B) and the metabolizable energy (ME) was investigated by regression analysis. The relationship between B and ME in 34 balance studies is given by B = 0.79 ME - 211.9 (r = 0.91). The ME at zero B [268.3 kJ (64.1kcal)/kg/24h] is equivalent to the maintenance energy requirement (MER). Paired data on 16 children were used to study the relationship between MER and the resting metabolic rate (RMR). The relationship between MER and RMR during measles, is at low levels of energy intake, is given by MER = 1.52 RMR - 140.9 kJ/kg/24h (r = 0.79). The factorial relationship between MER and RMR was estimated, and also the safe level of intake to supply the MER when ME represents between 76% and 84% of gross energy (GE). The safe level of GE intake, between 381 and 416 kJ/kg/24h (ie between 91.1 and 99.4 kcal/kg/24h) is very close to the WHO/FAD (1973) recommendations for growing children.

12. Duggan MB & Milner RDG (1986): Energy metabolism in healthy black Kenyan children. Br.J.Nutr. 56, 317-328.

Twenty-four healthy black Kenyan children, mean age 29 (SD 19) months, were studied over a 24 h period. Energy expenditure (EE) was determined using a ventilated-hood indirect calorimeter; measuring oxygen consumption and carbon dioxide production. Metabolizable energy intake was measured in twenty children. Anthropometric measurements were used to estimate surface area and lean body weight. The mean daily intake of metabolizable energy was 338.4 (SE 28.4) kJ; 70% of gross dietary energy being provided by carbohydrate. The level of postprandial EE was significantly (P < 0.05) higher than the resting level (112.6 (SE 0.47) and 11.38 (SE 0.37) kJ per h respectively) while the level of the postprandial respiratory quotient (RQ) was similar to the resting level (0.94 (SE 0.02) and 0.98 (SE 0.03) respectively). In 33% of total observations of the resting RQ the value was more than 1.0. These findings suggest that short-term fat storage may be a normal feature of metabolism in children, and also that the energy cost of (postprandial) fat synthesis is increased by a high-carbohydrate diet. Values for the resting metabolic rate and various estimators of body size were compared using regression analysis. It was evident that, in these young children with considerable variation in body composition, body weight remained a satisfactory metabolic size estimator.

13. Freedson PS, Katch VL, Gilliam TB & MacConnie S (1981): Energy expenditure in prepubescent children: influence of sex and age. Am.J.Clin.Nutr. 34, 1827-1830.

The purpose of this investigation was to examine the relationship between energy expenditure and speed for 6- and 7-yr-old children and to compare these data to published data for adults. Eight subjects (four boys, four girls) completed three treadmill tests at 67, 94, and 127.5 m . min-1 (k = 12 trials for the boys, 12 trials for the girls). Heart rate was monitored continuously and oxygen uptake (VO2) and carbon dioxide production (VCO2) were determined at each speed in order to estimate caloric expenditure. Sex differences were observed in the metabolic and heart rate responses to exercise. In comparison to the females, the energy expenditure (kcal . min-1) was 16 (p less than 0.05), 11 (p greater than 0.05) and 14 (p less than 0.05) percent higher for the males at the slow, medium, and fast speeds, respectively. Additionally, heart rate was 13 beats . min- 1 lower (p less than 0.05) for the males at a speed of 94 m. min-1. Differences in kcal . kg . min-1 between children and adults were observed (children higher). In contrast to adults' linear increase in energy expenditure with increasing speed, a curvilinear pattern was observed for prepubescent children. It was concluded that these sex and age effects must be considered when attempting to quantify children's daily energy expenditure and caloric requirements.

14. Gandra YR & Bradfield RB (1971): Energy expenditure and oxygen handling efficiency of anemic children. Am.J.Clin.Nutr. 24, 1451-1456.

The energy expenditure and oxygen handling efficiency of nonanemic and anemic primary school children was measured at school and at play in an isolated jungle fishing village before and after iron therapy. Typical daily energy expenditure was not dependent upon the degree of anemia. Standardized tests of oxygen handling efficiency showed that 88% of the variations in energy expenditure could be accounted for by multiple regression of heart rate, weight, and hemoglobin. Oxygen handling efficiency was affected adversely by abnormal hemoglobin levels.

15. Goran Ml, Kaskoun M, Johnson R. Martinez C, Kelly B & Hood V (1995): Energy expenditure and body fat distribution in Mohawk children. Pediatrics, 95, 89-95.

Department of Medicine and Nutritional Sciences, University of Vermont, Burlington. Epidemiologic studies suggest that Native Americans, including the Mohawk people, have a high prevalence of obesity, diabetes, and cardiovascular risk. However, current information on alterations in related variables such as energy metabolism and body composition in Native Americans is almost exclusively limited to already obese Pima adults living in the Southwest. The aim of this study was to characterize energy metabolism and body composition in young Mohawk children (17 girls, 11 boys; aged 4 to 7 years) as compared to Caucasian children (36 girls, 34 boys; aged 4 to 7 years). Total energy expenditure was measured by doubly labeled water, postprandial resting energy expenditure by indirect calorimetry, and activity energy expenditure was derived from the difference between total and resting energy expenditure. Fat and fat-free mass were estimated from bioelectrical resistance, and body fat distribution was estimated from skinfolds and circumferences. RESULTS. There were no significant effects of ethnic background or sex on body weight, height, or body mass index. Fat free mass was significantly higher in boys and fat mass was significantly higher in girls, with no effect of ethnic background. Chest skinfold thickness, the ratio of trunk skinfolds: extremity skinfolds, and the waist: hip ratio were significantly higher in Mohawk children by 2.5 mm, 0.09 units, and 0.03 units, respectively, independent of sex and fat mass. Total energy expenditure was significantly higher in Mohawk children compared to Caucasian (100 kcal/day in girls, 150 kcal/day in boys), independent of fat free mass and sex, due to a significantly higher physical activity-related energy expenditure. CONCLUSION. These data suggest that: 1) body fat is more centrally distributed in Mohawk relative to Caucasian children, and this effect is independent of sex and body fat content; 2) Mohawk children have a greater total energy expenditure than Caucasian children, independent of fat free mass, due to greater physical activity-related energy expenditure.

16. Ho Z. Zi HM, Bo L & Ping H (1988): Energy expenditure of pre-school children in a subtropical area. Wld.Rev.Nutr.Diet. 57, 75-94.

This study examines the appropriate energy intakes for preschool children in a subtropical area of China. A series of measurements were made on 181 children in four different seasons over a period of 1.5 years: body surface area, basal metabolic rate, dietary intakes, and the specific dynamic action of 8 common foods. The total energy expenditure of a sub-sample of children was calculated via daily activity records and measurements of the energy costs of 21 routine activities made using indirect calorimetry. The average daily energy expenditure for boys was 1,077.6 +- 37.0 kcal and for girls was 1,020.5 +- 43.7 kcal. Using this as the basis to calculate energy intake requirements and making allowances for growth and digestibility, an RDA of 1,500 of kcal/d was calculated as acceptable for this group of 5 year old children. [not original abstract].

17. Holmer I (1972): Oxygen uptake during swimming in man. .J.Appl.Physiol 33, 502-509.

It is possible to set the water flow rate with great accuracy in a recently constructed swimming flume, i.e., a kind of swimming "treadmill". Oxygen uptake, heart rate, and blood lactate concentrations were measured in three female and six male adult subject, with varying proficiency in swimming, while subjects swam three styles at different speeds. The same determinations were made during exercise on a Krogh bicycle ergometer and on a treadmill. The same determinations were made in 12 girl swimmers, 13-18 years old, but only during maximal running and maximal swimming. Minimal oxygen uptake during floating in a vertical position in nine subjects varied from 0.9 to 2.0 I.min-1. At a given swimming speed the trained swimmers were able to swim with a much lower oxygen uptake than subjects who were not trained swimmers. At a given oxygen uptake trained swimmers also swam much faster than the untrained swimmers. The front crawl proved to be the most economical style, as is the case in competition swimming. The back crawl was somewhat less economical and the breaststroke was the least economical style. Maximal oxygen uptake, maximal pulmonary ventilation, and maximal heart rate were significantly lower in swimming than in running or cycling, respectively.

18. Katch V, Becque MD, Marks C, Moorehead C & Rocchini A (1988): Oxygen uptake and energy output during walking of obese male and female adolescents. Am.J.Clin.Nutr. 47, 2632.

Department of Kinesiology, School of Medicine, University of Michigan, Ann Arbor. Oxygen uptake and steady-rate energy output of 7 obese male and 13 obese female adolescents (greater than 178% ideal body weight) walking at four different speeds (1.167, 1.5667, 1.7833, and 2.125 m/s) were studied. Body composition was measured by hydrostatic weighing, and steady-rate energy output by open circuit spirometry. Energy output was expressed as kJ/min (kcal/min) and indexed to body mass and fat-free mass. A 2-by-4 ANOVA (sex by speed) revealed significant differences in the energy output between the speed conditions. There was no significant difference between the sexes. A nonlinear increase in calorie output with increasing speed indicated a decreasing efficiency with increasing speed of walking. Possible reasons include biomechanical factors such as increased upper-body forward lean needed to maintain balance at faster speeds of movement, increased energy output due to increased inertia, extra energy output needed to accelerate the limbs and torso, and increased body fat.

19. Knuttgen HG (1967): Aerobic capacity of adolesents. .J.Appl.Physiol 22, 655-658.

Average values for a variety of anthropometric and physiologic parameters have been obtained for a representative group of American adolescents (15-18 years old) and of European ancestry. Both male (N = 95) and female (N = 95) subjects were studied at rest and at work on a bicycle ergometer. The mean values for the boys generally exceeded those for the girls, as body size exerted an important influence. At rest the boys had higher values for oxygen consumption, pulmonary ventilation, and metabolic rate VO2 per unit body size); the girls had a higher average heart rate. At maximal work the boys had higher values for oxygen consumption (for boys mean value = 3.34 liters/min, for girls mean value = 1.90 liters/min), pulmonary ventilation, and heart rate (for boys mean value = 196/min, for girls mean value = 193/min); the girls had a higher average ventilatory equivalent. When aerobic capacity was expressed in terms of body weight, the girls had a mean value of 33.6 and the boys 50.3 ml/kg per min. The prediction of aerobic capacity from steady-state heart rate reactions to submaximal work was enhanced by including the person's body weight in the calculation.

20. MacDougall JD, Roche PD, Bar-Or O & Moroz JR (1983): Maximal aerobic capacity of Canadian schoolchildren: prediction based on age-related oxygen cost of running. Int.J.Sports Med. 4, 194-198.

Timed distance runs were administered to a random sample of 2,683 schoolchildren aged 716 years. Oxygen uptake was then measured during level treadmill running over a range of submaximal speeds in a randomly selected subsample of 134 children with approximately equal representation according to age and sex. The VO2 - running speed relationship was found to be related to age, with the younger children having a greater VO2 per kg body weight than the older children when running at the same absolute speed. Based on the relationship found between measured VO2max and VO2max predicted according to field test performance, corrected for age-related differences in running efficiency, VO2max was predicted for all 2,683 children. When expressed per kg of body weight, VO2max was highest in girls at age 11 (approximately 44 ml/kg) and in boys at age 14 (approximately 54 ml/kg); however, differences among ages were nonsignificant. At all ages VO2max for the boys was significantly higher than that for the girls. At all ages, values were higher than those previously reported for Canadian schoolchildren.

21. Maffeis C, Schutz Y. Schena F. Zaffanello M & Pinelli L (1993): Energy expenditure during walking and running in obese and nonobese prepubertal children. J.Pediatr. 123, 193-199.

Department of Pediatrics, University of Verona, Italy. We measured body composition and energy expenditure during walking and running on a treadmill in 40 prepubertal children: 23 obese children (9.3 +/- 1.1 years of age; 46 +/- 10 kg (mean +/- SD)) and 17 nonobese matched control children (9.2 +/- 0.6 years of age; 30 +/- 5 kg). Energy expenditure was assessed by indirect calorimetry with a standard open-circuit method. At the same speed of exercise, the energy expenditure was significantly (p < 0.01) greater in obese than in control children, in both boys and girls. Expressed per kilogram of body weight or per kilogram of fat-free mass, the energy expenditure was comparable in the two groups. Obese children had a significantly (p < 0.01) larger pulmonary ventilatory response to exercise than did control children. Heart rate was comparable in boys and girls combined but significantly higher (p < 0.05) in obese subjects, if boys and girls were analyzed separately. These data indicate that walking and running are energetically more expensive for obese children than for children of normal body weight. The knowledge of these energy costs could be useful in devising a physical activity program to be used in the treatment of obese children.

22. McNaughton JW & Cahn AJ (1970): A study of the energy expenditure and food intake of five boys and four girls. Br.J.Nutr. 24, 345-355.

Assessments were made of the energy expenditure and food intake of five boys and four girls aged between 16 and 20 years. 2. The subjects recorded their activity over a 7-day period and weighed and recorded their food intake over the same period. The energy expended by them in performing specific activities, such as sitting, standing and walking, was measured by indirect calorimetry. The total daily energy expenditure of each subject was then counted. (Values were selected from the literature for the energy cost of the activities which were not measured.) 3. The following range of values was obtained for the energy cost per min of various activities: sitting 1.0-1.8 kcal; standing, 1.2-2.0 kcal; walking 2.0-7.5 kcal; office work 1.1-1.9 kcal; laboratory work 1.4-2.3 kcal; playing table tennis, 4.6 kcal; riding a bicycle, 3.66.0 kcal; running, 5.2-7.5 kcal. 4. The means and standard deviations for daily energy expenditure and for calorie intake. respectively, expressed in kcal, of the individual subjects were: for the boys 2677 +184 and 3348±668, 2285±91 and 2652+418, 2730±263 and 2985±625, 2638±338 and 2379±204, 2594±244 and 3150+692; for the girls 1939±234 and 2340+524, 2261±175 and 2064+376, 2131±148 and 2011±389, 2104±171 and 2454±469. 5. There was no correlation between the daily energy expenditure and calorie intake of any subject, nor was there any relation between the weight of individual subjects and either their total energy expenditure or calorie intake. 6. It is concluded that more precise methods of measuring the energy expenditure and calorie intake of individual subjects would need to be used in order to determine if there is any correlation between these two variables over short periods. 7. The results of this study tend to confirm the findings of other workers that calorie balance is only achieved over periods longer than 7 days.

23. Moore ME, Pond J & Korslund MK (1966): Energy expenditure of pre-adolescent girls. Measurements taken in the basal state and while walking. J.Am.Diet.Assoc. 49, 409-412.

The energy expenditure of twelve pre-adolescent girls was determined when each was in the basal state and while walking at a self-chosen speed. All basal metabolic rates were within +-9 per cent of the standard. Energy used for walking ranged from 53.3 to 90.8 calories per square meter of body surface per hour, or an increase of 119 and 206 per cent, respectively over basal metabolism. Differences in energy used for the same activity may be a factor in the relative ease with which an individual maintains caloric balance.

24. Morgan J & Mumford P (1981): Preliminary studies of energy expenditure in infants under six months of age. Acta Paediatr.Scand. 70, 15-19.

In the study energy expenditure measurements have been made by open circuit calorimetry on a number of occasions on four infants, with special reference to the energy cost of resting metabolism, activity and diet-induced thermogenesis. In addition, for two subjects the energy cost of growth was determined. The energy expended with respect to activity was highly variable among all subjects and it was postulated that this was a factor of great importance in the energy balance of young infants; indeed, the effect of diet-induced thermogenesis was enhanced by activity. A calculation of the total energy required to gain 1 g of wet tissue in two infants was found to be different. As their intakes were 'low' and 'high' though their weight gains were accelerated and slow respectively, the difference in the energy cost of growth has been discussed as a reason for this paradox.

25. Rose J. Gamble JG, Burgos A, Medeiros J & Haskell WL (1990): Energy expenditure index of walking for normal children and for children with cerebral palsy. Dev.Med.Child Neurol. 32, 333-340.

Children's Hospital at Stanford, Palo Alto, CA 94304. Energy expenditure indices (EEI) based on oxygen uptake and heart rate were used to compare the economy of walking at various speeds by normal and cerebral-palsied children. At low walking speeds, EEI values were high, indicating poor economy. At higher speeds the EEI values decreased until a range of maximum economy was reached. For normal children who were capable of walking beyond this range at higher speeds, the EEI increased again. This pattern was noted for both oxygen uptake and heart-rate indices. Mean EEI values based on oxygen uptake and heart rate for normal children were significantly lower and occurred at faster walking speeds than values for children with cerebral palsy. EEI based on either oxygen uptake or heart rate can be used clinically to provide objective information to help evaluate the influence on gait function of surgical intervention, ambulatory aids or orthotics.

26. Rose J. Gamble JG, Lee J. Lee R & Haskell WL (1991): The energy expenditure index: a method to quantitate and compare walking energy expenditure for children and adolescents. J.Pediatr.Orthop. 11, 571 -578.

Division of Orthopaedic Surgery, Stanford University Medical Center, California. Heart rate and walking speed were used to calculate an energy expenditure index (EEI), the ratio of heart rate per meter walked, for 102 normal subjects, age 6-18 years. Heart rate was measured at self-selected slow, comfortable, and fast walking speeds on the floor and on a motor-driven treadmill. At slow walking speeds (37 +/- 10 m/min) the EEI was elevated (0.71 +/- 0.32 beats/m), indicating poor economy. At comfortable speeds (70 +/- 11 m/min) the EEI values decreased to the maximum economy (0.47 +/- 0.13 beats/m). At fast speeds (101 +/13 m/min), the EEI increased (0.61 +/- 0.17 beats/m), indicating poor economy relative to comfortable speeds. A graph of the EEI versus walking speed provides a way to evaluate and compare energy expenditure in a clinical setting.

27. Rose J. Gamble JG, Medeiros J. Burgos A & Haskell WL (1989): Energy cost of walking in normal children and in those with cerebral palsy: comparison of heart rate and oxygen uptake. J.Pediatr.Orthop. 9, 276-279.

Division of Orthopaedics, Children's Hospital, Stanford, Palo Alto 94304. The rate of oxygen uptake can be used to assess energy expenditure during walking, but the necessary instrumentation is cumbersome, expensive, and usually unavailable in the clinical setting. Heart rate is an easily measured parameter, but its use as an index of energy expenditure in children has not been validated previously. The relationship between oxygen uptake and heart rate was found to be linear throughout a wide range of walking speeds for both children with cerebral palsy and normal children. There was no significant difference between the slope or the gamma-intercept of the lines For the two groups. These findings validate the use of heart rate as an index of energy expenditure for normal children and for children with cerebral palsy.

28. Silverman M & Anderson SD (1972): Metabolic cost of treadmill exercise in children. .J.Appl.Physiol 33, 696-698.

Four healthy children, aged 6-11 years, were studied while walking and running on a treadmill at speeds of between 1.6-6.4 km/hr and gradients of 0-20%. Measurements were made at each work level, of minute ventilation, oxygen consumption, and carbon dioxide production. A total of 98 work loads was studied. The results are expressed in terms of multiple linear regression analyses relating oxygen consumption, body weight, treadmill speed, and treadmill gradient. Differences from previously published studies are discussed.

29. Spady DW (1980): Total daily energy expenditure of healthy, free ranging school children. Am.J.Clin.Nutr. 33, 766-775.

This study present estimates of the energy expenditure of a group of school children. Two data sets were used; one based on the direct measurement of oxygen consumption VO2 of 36 children while sitting and used to estimate resting energy expenditure (REE) during the day and one based on the indirect estimation of VO2 by the use of heart rate counters and used to measure energy expenditure while awake (EEA) in 22 children. In all cases night-time energy expenditure was estimated from tables of basal metabolic rate (BMR). These measures permitted estimates to be made of maintenance energy expenditure (MEE) when MEE = (REE x time out of bed) + (BMR x time in bed); total daily energy expenditure (TDEE) when TDEE = (EM x time out of bed) + (BMR x time out of bed); and energy for activity (EAc) when EAc = (TDEE - MEE). Mean TDEE for boys was 2164 kcal/day and for girls 1716 kcal/day; mean MEE for boys was 1503 kcal/day and for girls 1263 kcal/day; mean EAc for boys was 673 kcal/day and for girls was 434 kcal/day. All differences are statistically significant and, with the exception of EAc, remain so when expressed in terms of lean body mass. Estimates of MEE are close to the theoretical estimates for MEE of 105 kcal/kg. The lower TDEE in girls suggests that the recommended dietary allowances for energy should be less than for boys.

30. Spurr GB & Reina JC (1986): Marginal malnutrition in school-aged Colombian boys: body size and energy costs of walking and light load carrying. Hum.Nutr.Clin.Nutr. 40C, 409-419.

The energy expenditure of 93 Colombian boys aged 6-16 years of age and 10 adult American males was measured while walking on a treadmill at 3 mph and 0, 4, 8 and 12 per cent grades with and with backpack loads of 3 (6-8 year), 6 (10-12 year) and 9 kg (14-16 year and adults). The boys were also divided into nutritionally normal and marginally malnourished, based on their weight-for-age and weight-for-height. The primary dependence of energy expenditure on body weight or body weight plus load was not affected by nutritional status, and the results of both adults and control and malnourised children fell on the same straight line at a given treadmill grade, indicating that the undernourished subjects would expend the same energy as nutritionally normal boys and adult subjects for a given load carried. The undernourished boys worked at a higher percentage VO2max than control subjects when load carrying.

31. Spurr GB & Reina JC (1989): Energy expenditure/basal metabolic rate ratios in normal and marginally malnourished Colombian children 6-16 years of age. Eur.J.Clin.Nutr. 43, 515527.

Measurements of basal (BMR) and resting (RMR) metabolic rates, maintenance (MEE) and total daily energy expenditure (TDEE) have been made in Colombian children 6-16 years of age classified as nutritionally normal (boys, n = 129; girls; n = 72) and marginally malnourished (bodys, n = 171; girls, n = 74). TDEE/BMR ratios were calculated for comparison with those suggested by FAO/WHO/UNU (1985) and to provide data for children less than 10 years of age. TDEE was measured in free-living, individually calibrated subjects by the heart-rate method. TDEE/BMR increased significantly with age in boys from 1.60 to 1.84 in control subjects and 1.16 to 1.92 in malnourished boys. There was no significant increase with age in the girls. There were no statistically significant differences between nourished groups but girls had significantly lower values than boys. There was a greater rate of increase in TDEE than BMR with age and girls spent more time in light activities and less in high level activities than boys.

32. Spurr GB, Reina JC & Barac-Nieto M (1986): Marginal malnutrition in school-aged Colombian boys: metabolic rate and estimated daily energy expenditure. Am.J.Clin.Nutr. 44, 113126.

Total daily energy expenditure (TDEE) and energy expenditure in activity (EAc) were estimated in 114 free-ranging, nutritionally normal, and undernourished boys 6-16 yr of age by measuring basal and resting metabolic rates, average daily heart rate while awake, and oxygen consumption and heart rate during exercise on a treadmill. Mean daily heart rates were in the range of exercising heart rates and gave reasonable estimates of TDEE and EAc. TDEE increased with age (p<0.001) and was reduced in undernourished boys (p=0.011). Results indicate that nutritional group differences in TDEE were due to differences in body size. EAc increased with age but did not show significant differences between nutritional groups, indicating that in the marginal malnutrition of school-aged children, reduced growth and associated economy of energy expenditure in locomotion is sufficient physiological adaptation. Peer pressure in school and play activities may interfere with the protective mechanism of reduced activity.

33. Thorstensson A (1986): Effects of moderate external loading on the aerobic demand of submaximal running in men and 10 year-old boys. Eur.J.Appl.Physiol 55, 569-574.

The effects of moderate external loading on the aerobic demand of submaximal running were studied in habitually active adult men (29-37 yrs) and 10 year-old boys. The load was symmetrically placed around the trunk and adjusted to correspond to 10% of body weight. Running was performed on a treadmill at 8, 10 and 11 km.h-1 (2.2, 2.8 and 3.1 m.s-1). A small, but consistent decrease in net oxygen uptake (gross oxygen uptake in minus calculated basal metabolic rate) with load was observed in both groups at all speeds, except for the men at 8 km.h-1. The decrease was larger for the boys and tended to enhance with speed. The boys had a higher net oxygen uptake than the adults at all unladen running velocities, whereas the difference in the loaded condition was significant only at the highest speed. The decrease in net oxygen uptake with load could not be directly correlated with differences in body weight or step frequency. It is hypothesized that a difference in the utilization of muscle elastic energy could underlie part of the age and load dependent changes observed in running economy.

34. Torun B. Chew F & Mendoza RD (1983): Energy costs of activities of preschool children. Nutr.Res. 3, 401-406.

Energy expenditures were measured in 47 children, 17-45 months old, under basal metabolic conditions (mean ± sd: 38 ± 5 cal/kg/min) and while resting supine (44 ± 5), sitting (47 ± 6), walking leisurely on level ground (,71 +- 8), walking rapidly at a grade (98 +- 11), climbing and descending ramps (87 ± 7), climbing stairs (94 ± 8) and riding on a tricycle (73 ± 5). These values are greater than those reported in adults per unit of body weight. Consequently, the energy costs of activities determined in adults should not be applied to preschool children. Our results support the following recommendations to calculate the energy expenditure of preschool children in time-and-motion studies: a) use the energy costs of activities that have been measured in children, whenever available; and b) use 1.2, 2 and 2.5 times the child's basal metabolism, respectively, for sedentary, light and moderately heavy activities, or use the values determined in adults per unit of body weight multiplied by 2 for sedentary activities, and by 1.2 for all other activities.

35. Waters RL, Hislop HJ, Thomas L & Campbell J (1983): Energy cost of walking in normal children and teenagers. Dev.Med. Child Neurol. 25, 184-188.

Oxygen consumption during free level walking was determined in 114 children and teenaged subjects between the ages of 6 and 19 years and compared with a group of 47 normal adults. Subjects were divided into two age groups: children (6-12 years) and adolescents (13-19 years). The mean rate of oxygen uptake for children was significantly greater, 15.3 ml/kg/min, than the value for teenaged subjects, 12.9 ml/kg/mint The oxygen cost to walk a unit distance (meter) was higher in children than adolescent subjects. The mean values averaged 0.22 ml/kg/min and 0.18 ml/kg/min respectively. The data on heart rate paralleled the findings on oxygen consumption. The mean heart rate for children, 114 beats per minute (bpm), was significantly higher than the mean values for adolescent subjects, 97 bpm.

36. Waters RL, Lunsford BR, Perry J & Byrd R (1988): Energy-speed relationship of walking: standard tables. J.Orthop.Res. 6, 215-222.

Department of Surgery, Rancho Los Amigos Medical Center, Downey 90242. The energy expenditure of level walking was measured in 260 normal male and female subjects walking around a 60.5m-circular outdoor track. Subjects were divided into four age groups (children, 612 years; teens; young adults, 20-59 years; and senior adults, 60-80 years). Oxygen consumption was measured with a modified Douglas Bag technique during the fourth and fifth minutes of each trial. Standard tables according to age and sex were derived for the average energy expenditure (rate of oxygen uptake, energy cost per meter, and heart rate) and for the gait characteristics (speed, cadence, stride length) at the subjects' customary slow, normal, and fast walking speeds. Statistical analysis was performed to determine the energy-speed relationship for the different age groups to derive normative tables for the rate of oxygen uptake throughout the range of customary walking velocities.

37. Waxman M & Stunkard AJ (1980): Caloric intake and expenditure of obese boys. J.Pediatr. 96, 187-193.

Caloric intake and expenditure of children in four families were assessed by nonparticipant observations of family dinners and school lunches. In each family there were one obese boy and one nonobese brother whose ages were within two years of each other. For family dinners the nonobese brother served as a control; for school lunches, a nonobese peer served as a control. The obese boys consumed more calories (766 +/- 290) than did their nonobese brothers at dinner (504 +/- 183) and far more (907 +/- 217) than their nonobese peers at lunch (500 +/- 386). The obese boys also ate faster (65.7 +/- 37.0 kcal/minute) than their brothers at dinner (31.7 +/- 13.8 kcal/minute) and far faster (103.5 +/- 40.9 kcal/minute) than their nonobese peers at lunch (46.2 +/- 22.5 kcal/minute). Time-sampled activity assessments showed the obese boys far less active than their controls inside the home, slightly less active outside the home, and equally active at school. When these activity values were converted into energy expenditure by measurement of oxygen consumption, obese boys expended more calories in moving than did their controls; as a result, there was no difference in energy expenditure between obese and nonobese boys at home and greater energy expenditure outside the home and at school. Increased intake, thus, and not decreased caloric output maintained the obesity of these four boys. In this respect, obesity in childhood may differ from obesity in adult life.

Foreign language references

1. Voronina NV (1994): [Daily energy expenditures and energy requirements of pupils at general education schools in the Republic of Uzbekistan]. Gig.Sanit. 20-21.

Evaluation of daily energy expenditures was made on the basis of study of schoolchildren's time budget and their energy expenditures at the main body postures and during various types of activity. The data were used for substantiation of the physiological energy requirements to schoolchildren of different age and sex. Recommendations on the rations for schoolchildren with consideration for age and sex were made