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Nutrition Activities For Young Children
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| Physical activity and energy expenditure in young children In recent years, a global epidemic of pediatric obesity has affected both preschool and older children. Reduced total energy expenditure (TEE) secondary to a decline in physical activity could be a contributing factor. Many observers believe that increased population and physical activity could alleviate the obesity epidemic by directly increasing TEE or because coupling of intake and expenditure could be poor at low levels of TEE. continued below... |
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However, the relation between free-living TEE and physical activity is currently unclear for all populations, particularly children, in part because of practical difficulties associated with the measurement office-living TEE and physical activity.
Researchers recruited a socioeconomically representative group of children in their preschool year (n = 36) and first school year (n = 68) by recruiting from selected postal sectors in the Glasgow area. The researchers attempted to measure simultaneously TEE (by DLW), physical activity, and sedentary behavior (by accelerometry). After collection of a baseline (predose) urine sample all children received a sterilized, weighed dose of mL/kg body weight 180-labeled water mixed with mL/kg % enriched deuterium oxide. Urine samples were obtained from the preschool children on days 1 and 7 after dosing and from the school-aged children on days 1 and 10 after dosing. Isotopic enrichments of urine samples were measured by isotope ratio mass spectrometry. Researchers estimated carbon dioxide production rate from the differential disappearance of the 2 isotopes.
In 32 of the school-aged children, resting energy expenditure (REE) was measured by ventilated-hood indirect calorimetry. Total amount of physical activity, time spent in different intensities of physical activity, and sedentary behavior was measured with use of accelerometry. Children wore the CSA/MTI uniaxial accelerometer during waking hours for a period of 3 days (preschool age, n = 36) and 7 days to 10 days (school age, n = 68) on the right hip. The current paradigm is that variation in engagement in moderate-intensity physical activity may be the principal determinant of variation in PAL in free-living subjects. Acceptance of this paradigm has led to suggestions that future clinical and public health initiatives should promote physical activities of fight-moderate intensity to influence energy balance. Although this paradigm and its subsequent recommendations could seem uncontroversial, they are based on limited empirical evidence at present and require testing in different settings or populations. The present study in young children suggests that engagement in MVPA makes a relatively minor contribution to PAL, TEE, or AEE. That is not to say that it could not do so in the future. However, in this predominantly sedentary sample, variation in activity was limited, and the main determinant of variation in PAL was the "split" between sedentary behavior and light-intensity activity.
In the present study the researchers observed an inverse association between PAL and time spent sedentary, as well as a positive association between PAL and time spent in light-intensity activities. This observation, combined with the high engagement in sedentary behavior, suggests that a shift from time spent in sedentary behavior toward light-intensity activities might be a realistic and promising strategy for increasing TEE in young children.
C Montgomery, J Reilly, D Jackson, L Kelly, C Slater, J Paton, S Grant. Relation between physical activity and energy expenditure in a representative sample of young children. Am J Clin Nutr 80(3):591-596 (September 2004) [Correspondence: JJ Reilly, University of Glasgow, Division of Developmental Medicine, Yorkhill Hospital, Glasgow, G3 8SJ Scotland, United Kingdom. E-mail: .]