Total Energy Expenditure in Children Assessed by Doubly Labeled Water and Physical Activity Questionnaire

Abstract

Accurate assessment of physical activity and energy expenditure in children is crucial for understanding physical activity status and guiding prevention efforts. PURPOSE: This study was to assess the total daily energy expenditure in children in Hong Kong using doubly labeled water (DLW) method and physical activity questionnaire. METHODS: Eight 7–9 years old non-obese boys (Mean ± SD, age: 8.1 ± 0.6 y; Body mass: 25.4 ± 3.0 kg; Body mass index: 16.0 ±2.1) recruited from local primary school participated in this study. Basal metabolic rate (BMR) was determined by indirect calorimetry. Total daily energy expenditure (TEE) was measured over a 10-day period by DLW method (TEEDLW) and a 3-day physical activity questionnaire (TEEQ). Energy intake (EI) was estimated by a 3-day weighed food diary. The physical activity level (PAL) was calculated from TEEDLW/BMR and the 3-day heart rate (HR) record. RESULTS: The TEE and DLW method showed similar results in assessing TEE in the schoolchildren (1900.7 ± 293.7 kcal and 1756.4 ± 296.5 kcal, NS), whereas the EI was 1705.8 ± 129.0 kcal. Reported physical activity energy expenditure and EI from food diary record during weekend (35.7 ± 3.5 METs·min, 1779.2 ± 326.2 kcal) was lower than that during weekday (39.3 ± 2.6 METs.min, 1961.6 ± 321.3 kcal, P<0.05). PAL of this group was 1.49 ± 0.26 on weekdays and 1.48 ± 0.14 at weekend. The HR record showed that these children spent only 1.3% of their time in moderate physical activity, i.e., HR 140–160 bpm, within the 3-day period. Only one child experienced a single 10-minute period with the HR above 140 bpm during the monitored weekdays. CONCLUSIONS: The results suggested that the physical activity level in these Hong Kong primary schoolchildren was alarmingly low. The 3-d physical activity questionnaire produced results similar to DLW method in estimating the total energy expenditure in these schoolchildren.