Relation between physical activity and energy expenditure in a representative sample of young children.
BACKGROUND
Strategies for the prevention and treatment of childhood obesity require a better understanding of the relation between the pattern of free-living physical activity and total energy expenditure (TEE).


OBJECTIVE
We assessed the relations between TEE and physical activity level (PAL) during engagement in different intensities of physical activity.


METHODS
We used a cross-sectional study of 104 children (median age: 5.4 y) in Scotland. TEE was measured with use of doubly labeled water (DLW), and resting energy expenditure was predicted to determine PAL. Time spent sedentary and in light-intensity activity and in moderate- and vigorous-intensity physical activity (MVPA) was assessed by accelerometry concurrent with DLW measurements. Correlation and regression were used to assess the relations between measures of sedentary behavior, intensities of activity, and PAL as the dependent variable.


RESULTS
Time spent sedentary was negatively correlated with PAL (r = -0.33, P < 0.01), and time spent in light-intensity activity was positively correlated with PAL (r = 0.31, P < 0.01). In multiple regression analyses, both time spent sedentary and in light-intensity activities were significantly associated with PAL. Time spent in MVPA was not associated with PAL; engagement in MVPA was limited in this sample (median: 3% of waking hours; range: 0-14%). PAL was significantly higher in boys than in girls.


CONCLUSIONS
In this sample and setting, PAL was not influenced by engagement in MVPA but was influenced by time spent sedentary and in light-intensity activities. This study suggests that in young children, MVPA could make only a minor contribution to free-living TEE and PAL.
Montgomery
Colette
C
Division of Developmental Medicine, University of Glasgow, Yorkhill Hospital, Glasgow G3 8SJ, Scotland, United Kingdom.
Reilly
John J
JJ
Jackson
Diane M
DM
Kelly
Louise A
LA
Slater
Christine
C
Paton
James Y
JY
Grant
Stan
S
D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003903:Deuterium / Q000652:urine; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic; D009765:Obesity / Q000453:epidemiology / Q000209:etiology / Q000378:metabolism; D010103:Oxygen Isotopes / Q000652:urine; D015995:Prevalence; D012044:Regression Analysis; D012606:Scotland / Q000453:epidemiology; D013997:Time Factors; D014867:Water / Q000378:metabolism
D010103:Oxygen Isotopes; D014867:Water; D003903:Deuterium