Determinants Of Daily Energy Expenditure In Active Kenyan Children

Abstract

Integrating data on physical activity and energy expenditure in diverse non-laboratory conditions is central to a complete understanding of the etiology of obesity, coronary heart disease, osteoporosis, cancer and other chronic diseases. PURPOSE: To determine the effects of body mass (BM) and physical activity on daily energy expenditure (DEE) in a cohort of rural Kenyan children from the Nandi region, where many elite Kenyan runners come from. METHODS: Physical activity levels and patterns in 30 Kenyan children (aged 14±1 yrs, mean±s.d.), with an average body mass index of 16±2 kg·m2 were assessed by uni-axial accelerometry for 7 consecutive days. DEE was determined using the doubly labeled water method. RESULTS: Kenyan children accumulated an average of 956±215 × 103 accelerometer counts per day (CPD); with a mean engagement in moderate to vigorous physical activity (MVPA) of 116±34 counts per minute (CPM) which was 14.5% of the monitored time; using Puyau cut-points (>3200 CPM). Kenyan children engaged in 77 min of MVPA bouts (bout = least 5 min of consecutive MVPA, allowing for 20% of interruption within a bout i.e. if a bout was exactly 5 min, then 1 min interruption was permitted). The DEE for Kenyan children was 12.2±3.4 MJ/day. A multiple stepwise linear regression model showed that 40.3% of the variance in DEE could be predicted by CPD (Partial r2 = 20.5%; P =0.007) and body mass (Partial r2 = 19.8%; P = 0.018). CONCLUSION: Body mass and physical activity as assessed by uni-axial accelerometry are major predictors of DEE in active children.