Measurement of resting energy expenditure in infants.
OBJECTIVE
The method for measurement of basal metabolic rate (BMR) using indirect calorimetry in adults is well established but is impractical in infants.


METHODS
In this prospective study energy expenditure was measured using indirect calorimetry in 14 infants when sleeping and when lying quietly awake.


RESULTS
Sleeping metabolic rate (SMR) was lower than energy expenditure (EE) measured in the same infants in a quiet resting state (mean difference [SD]: 297 [162] kJ/d; P < 0.005; 55 [33.4] kJ/kg per day; P < 0.005). The correlation within individuals suggests that these differences are related to the level of arousal. Awake EE, but not SMR, was significantly greater than estimated BMR using the FAO/WHO/UNU predictive equation.


CONCLUSIONS
In infants, the level of arousal during measurement of EE can significantly impact on the interpretation of EE results. A standardized method for the measurement of EE in infants using indirect calorimetry is proposed.
Bines
J E
JE
Gastroenterology and Clinical Nutrition, Royal Children's Hospital, Paediatrics, University of Melbourne, Melbourne, Victoria, Australia. julie.bines@rch.org.au
Truby
H D
HD
D001481:Basal Metabolism; D002153:Calorimetry, Indirect / Q000379:methods*; D003550:Cystic Fibrosis / Q000378:metabolism*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010101:Oxygen Consumption; D011446:Prospective Studies; D012890:Sleep